Java tutorial
/* * Copyright (C) 2006 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.liu.hz.view; import com.google.common.collect.Lists; import com.liu.hz.R; import android.annotation.TargetApi; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.PixelFormat; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.os.Build; import android.support.v4.view.KeyEventCompat; import android.util.AttributeSet; import android.util.SparseBooleanArray; import android.view.FocusFinder; import android.view.KeyEvent; import android.view.SoundEffectConstants; import android.view.View; import android.view.ViewDebug; import android.view.ViewGroup; import android.view.ViewParent; import android.view.accessibility.AccessibilityEvent; import android.view.accessibility.AccessibilityNodeInfo; import android.widget.ArrayAdapter; import android.widget.Checkable; import android.widget.ListAdapter; import android.widget.RemoteViews.RemoteView; import java.util.ArrayList; /* * Implementation Notes: * * Some terminology: * * index - index of the items that are currently visible * position - index of the items in the cursor */ /** * A view that shows items in a vertically scrolling list. The items * come from the {@link ListAdapter} associated with this view. * * <p>See the <a href="{@docRoot}guide/topics/ui/layout/listview.html">List View</a> * guide.</p> * * @attr ref android.R.styleable#ListView_entries * @attr ref android.R.styleable#ListView_divider * @attr ref android.R.styleable#ListView_dividerHeight * @attr ref android.R.styleable#ListView_headerDividersEnabled * @attr ref android.R.styleable#ListView_footerDividersEnabled */ @RemoteView public class ListView extends AbsListView { /** * Used to indicate a no preference for a position type. */ static final int NO_POSITION = -1; /** * When arrow scrolling, ListView will never scroll more than this factor * times the width of the list. */ private static final float MAX_SCROLL_FACTOR = 0.33f; /** * When arrow scrolling, need a certain amount of pixels to preview next * items. This is usually the fading edge, but if that is small enough, * we want to make sure we preview at least this many pixels. */ private static final int MIN_SCROLL_PREVIEW_PIXELS = 2; /** * A class that represents a fixed view in a list, for example a header at the top * or a footer at the bottom. */ public static class FixedViewInfo { /** The view to add to the list */ public View view; /** The data backing the view. This is returned from {@link ListAdapter#getItem(int)}. */ public Object data; /** <code>true</code> if the fixed view should be selectable in the list */ public boolean isSelectable; } private ArrayList<FixedViewInfo> mHeaderViewInfos = Lists.newArrayList(); private ArrayList<FixedViewInfo> mFooterViewInfos = Lists.newArrayList(); Drawable mDivider; int mDividerHeight; Drawable mOverScrollHeader; Drawable mOverScrollFooter; private boolean mIsCacheColorOpaque; private boolean mDividerIsOpaque; private boolean mHeaderDividersEnabled; private boolean mFooterDividersEnabled; private boolean mAreAllItemsSelectable = true; private boolean mItemsCanFocus = false; // used for temporary calculations. private final Rect mTempRect = new Rect(); private Paint mDividerPaint; // the single allocated result per list view; kinda cheesey but avoids // allocating these thingies too often. private final ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); // Keeps focused children visible through resizes private FocusSelector mFocusSelector; public ListView(Context context) { this(context, null); } public ListView(Context context, AttributeSet attrs) { this(context, attrs, R.attr.listViewStyle); } public ListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ListView, defStyle, 0); CharSequence[] entries = a.getTextArray(R.styleable.ListView_android_entries); if (entries != null) { setAdapter(new ArrayAdapter<CharSequence>(context, android.R.layout.simple_list_item_1, entries)); } final Drawable d = a.getDrawable(R.styleable.ListView_divider); if (d != null) { // If a divider is specified use its intrinsic width for divider width setDivider(d); } final Drawable osHeader = a.getDrawable(R.styleable.ListView_overScrollHeader); if (osHeader != null) { setOverscrollHeader(osHeader); } final Drawable osFooter = a.getDrawable(R.styleable.ListView_overScrollFooter); if (osFooter != null) { setOverscrollFooter(osFooter); } // Use the width specified, zero being the default final int dividerHeight = a.getDimensionPixelSize(R.styleable.ListView_dividerHeight, 0); if (dividerHeight != 0) { setDividerHeight(dividerHeight); } mHeaderDividersEnabled = a.getBoolean(R.styleable.ListView_headerDividersEnabled, true); mFooterDividersEnabled = a.getBoolean(R.styleable.ListView_footerDividersEnabled, true); a.recycle(); } /** * @return The maximum amount a list view will scroll in response to * an arrow event. */ public int getMaxScrollAmount() { return (int) (MAX_SCROLL_FACTOR * (getBottom() - getTop())); } /** * Make sure views are touching the top or bottom edge, as appropriate for * our gravity */ private void adjustViewsUpOrDown() { final int childCount = getChildCount(); int delta; if (childCount > 0) { View child; if (!mStackFromBottom) { // Uh-oh -- we came up short. Slide all views up to make them // align with the top child = getChildAt(0); delta = child.getTop() - mListPadding.top; if (mFirstPosition != 0) { // It's OK to have some space above the first item if it is // part of the vertical spacing delta -= mDividerHeight; } if (delta < 0) { // We only are looking to see if we are too low, not too high delta = 0; } } else { // we are too high, slide all views down to align with bottom child = getChildAt(childCount - 1); delta = child.getBottom() - (getHeight() - mListPadding.bottom); if (mFirstPosition + childCount < mItemCount) { // It's OK to have some space below the last item if it is // part of the vertical spacing delta += mDividerHeight; } if (delta > 0) { delta = 0; } } if (delta != 0) { offsetChildrenTopAndBottomUnhide(-delta); } } } /** * Add a fixed view to appear at the top of the list. If addHeaderView is * called more than once, the views will appear in the order they were * added. Views added using this call can take focus if they want. * <p> * NOTE: Call this before calling setAdapter. This is so ListView can wrap * the supplied cursor with one that will also account for header and footer * views. * * @param v The view to add. * @param data Data to associate with this view * @param isSelectable whether the item is selectable */ public void addHeaderView(View v, Object data, boolean isSelectable) { if (mAdapter != null && !(mAdapter instanceof HeaderViewListAdapter)) { throw new IllegalStateException( "Cannot add header view to list -- setAdapter has already been called."); } FixedViewInfo info = new FixedViewInfo(); info.view = v; info.data = data; info.isSelectable = isSelectable; mHeaderViewInfos.add(info); // in the case of re-adding a header view, or adding one later on, // we need to notify the observer if (mAdapter != null && mDataSetObserver != null) { mDataSetObserver.onChanged(); } } /** * Add a fixed view to appear at the top of the list. If addHeaderView is * called more than once, the views will appear in the order they were * added. Views added using this call can take focus if they want. * <p> * NOTE: Call this before calling setAdapter. This is so ListView can wrap * the supplied cursor with one that will also account for header and footer * views. * * @param v The view to add. */ public void addHeaderView(View v) { addHeaderView(v, null, true); } @Override public int getHeaderViewsCount() { return mHeaderViewInfos.size(); } /** * Removes a previously-added header view. * * @param v The view to remove * @return true if the view was removed, false if the view was not a header * view */ public boolean removeHeaderView(View v) { if (mHeaderViewInfos.size() > 0) { boolean result = false; if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeHeader(v)) { if (mDataSetObserver != null) { mDataSetObserver.onChanged(); } result = true; } removeFixedViewInfo(v, mHeaderViewInfos); return result; } return false; } private void removeFixedViewInfo(View v, ArrayList<FixedViewInfo> where) { int len = where.size(); for (int i = 0; i < len; ++i) { FixedViewInfo info = where.get(i); if (info.view == v) { where.remove(i); break; } } } /** * Add a fixed view to appear at the bottom of the list. If addFooterView is * called more than once, the views will appear in the order they were * added. Views added using this call can take focus if they want. * <p> * NOTE: Call this before calling setAdapter. This is so ListView can wrap * the supplied cursor with one that will also account for header and footer * views. * * @param v The view to add. * @param data Data to associate with this view * @param isSelectable true if the footer view can be selected */ public void addFooterView(View v, Object data, boolean isSelectable) { // NOTE: do not enforce the adapter being null here, since unlike in // addHeaderView, it was never enforced here, and so existing apps are // relying on being able to add a footer and then calling setAdapter to // force creation of the HeaderViewListAdapter wrapper FixedViewInfo info = new FixedViewInfo(); info.view = v; info.data = data; info.isSelectable = isSelectable; mFooterViewInfos.add(info); // in the case of re-adding a footer view, or adding one later on, // we need to notify the observer if (mAdapter != null && mDataSetObserver != null) { mDataSetObserver.onChanged(); } } /** * Add a fixed view to appear at the bottom of the list. If addFooterView is called more * than once, the views will appear in the order they were added. Views added using * this call can take focus if they want. * <p>NOTE: Call this before calling setAdapter. This is so ListView can wrap the supplied * cursor with one that will also account for header and footer views. * * * @param v The view to add. */ public void addFooterView(View v) { addFooterView(v, null, true); } @Override public int getFooterViewsCount() { return mFooterViewInfos.size(); } /** * Removes a previously-added footer view. * * @param v The view to remove * @return * true if the view was removed, false if the view was not a footer view */ public boolean removeFooterView(View v) { if (mFooterViewInfos.size() > 0) { boolean result = false; if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeFooter(v)) { if (mDataSetObserver != null) { mDataSetObserver.onChanged(); } result = true; } removeFixedViewInfo(v, mFooterViewInfos); return result; } return false; } /** * Returns the adapter currently in use in this ListView. The returned adapter * might not be the same adapter passed to {@link #setAdapter(ListAdapter)} but * might be a {@link android.widget.WrapperListAdapter}. * * @return The adapter currently used to display data in this ListView. * * @see #setAdapter(ListAdapter) */ @Override public ListAdapter getAdapter() { return mAdapter; } /** * Sets the data behind this ListView. * * The adapter passed to this method may be wrapped by a {@link android.widget.WrapperListAdapter}, * depending on the ListView features currently in use. For instance, adding * headers and/or footers will cause the adapter to be wrapped. * * @param adapter The ListAdapter which is responsible for maintaining the * data backing this list and for producing a view to represent an * item in that data set. * * @see #getAdapter() */ @Override public void setAdapter(ListAdapter adapter) { if (mAdapter != null && mDataSetObserver != null) { mAdapter.unregisterDataSetObserver(mDataSetObserver); } resetList(); mRecycler.clear(); if (mHeaderViewInfos.size() > 0 || mFooterViewInfos.size() > 0) { mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter); } else { mAdapter = adapter; } mOldSelectedPosition = INVALID_POSITION; mOldSelectedRowId = INVALID_ROW_ID; // AbsListView#setAdapter will update choice mode states. super.setAdapter(adapter); if (mAdapter != null) { mAreAllItemsSelectable = mAdapter.areAllItemsEnabled(); mOldItemCount = mItemCount; mItemCount = mAdapter.getCount(); checkFocus(); mDataSetObserver = new AdapterDataSetObserver(); mAdapter.registerDataSetObserver(mDataSetObserver); mRecycler.setViewTypeCount(mAdapter.getViewTypeCount()); int position; if (mStackFromBottom) { position = lookForSelectablePosition(mItemCount - 1, false); } else { position = lookForSelectablePosition(0, true); } setSelectedPositionInt(position); setNextSelectedPositionInt(position); if (mItemCount == 0) { // Nothing selected checkSelectionChanged(); } } else { mAreAllItemsSelectable = true; checkFocus(); // Nothing selected checkSelectionChanged(); } requestLayout(); } /** * The list is empty. Clear everything out. */ @Override void resetList() { // The parent's resetList() will remove all views from the layout so we need to // cleanup the state of our footers and headers clearRecycledState(mHeaderViewInfos); clearRecycledState(mFooterViewInfos); super.resetList(); mLayoutMode = LAYOUT_NORMAL; } private void clearRecycledState(ArrayList<FixedViewInfo> infos) { if (infos != null) { final int count = infos.size(); for (int i = 0; i < count; i++) { final View child = infos.get(i).view; final LayoutParams p = (LayoutParams) child.getLayoutParams(); if (p != null) { p.recycledHeaderFooter = false; } } } } /** * @return Whether the list needs to show the top fading edge */ private boolean showingTopFadingEdge() { final int listTop = getScrollY() + mListPadding.top; return (mFirstPosition > 0) || (getChildAt(0).getTop() > listTop); } /** * @return Whether the list needs to show the bottom fading edge */ private boolean showingBottomFadingEdge() { final int childCount = getChildCount(); final int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); final int lastVisiblePosition = mFirstPosition + childCount - 1; final int listBottom = getScrollY() + getHeight() - mListPadding.bottom; return (lastVisiblePosition < mItemCount - 1) || (bottomOfBottomChild < listBottom); } @Override public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate) { int rectTopWithinChild = rect.top; // offset so rect is in coordinates of the this view rect.offset(child.getLeft(), child.getTop()); rect.offset(-child.getScrollX(), -child.getScrollY()); final int height = getHeight(); int listUnfadedTop = getScrollY(); int listUnfadedBottom = listUnfadedTop + height; final int fadingEdge = getVerticalFadingEdgeLength(); if (showingTopFadingEdge()) { // leave room for top fading edge as long as rect isn't at very top if ((mSelectedPosition > 0) || (rectTopWithinChild > fadingEdge)) { listUnfadedTop += fadingEdge; } } int childCount = getChildCount(); int bottomOfBottomChild = getChildAt(childCount - 1).getBottom(); if (showingBottomFadingEdge()) { // leave room for bottom fading edge as long as rect isn't at very bottom if ((mSelectedPosition < mItemCount - 1) || (rect.bottom < (bottomOfBottomChild - fadingEdge))) { listUnfadedBottom -= fadingEdge; } } int scrollYDelta = 0; if (rect.bottom > listUnfadedBottom && rect.top > listUnfadedTop) { // need to MOVE DOWN to get it in view: move down just enough so // that the entire rectangle is in view (or at least the first // screen size chunk). if (rect.height() > height) { // just enough to get screen size chunk on scrollYDelta += (rect.top - listUnfadedTop); } else { // get entire rect at bottom of screen scrollYDelta += (rect.bottom - listUnfadedBottom); } // make sure we aren't scrolling beyond the end of our children int distanceToBottom = bottomOfBottomChild - listUnfadedBottom; scrollYDelta = Math.min(scrollYDelta, distanceToBottom); } else if (rect.top < listUnfadedTop && rect.bottom < listUnfadedBottom) { // need to MOVE UP to get it in view: move up just enough so that // entire rectangle is in view (or at least the first screen // size chunk of it). if (rect.height() > height) { // screen size chunk scrollYDelta -= (listUnfadedBottom - rect.bottom); } else { // entire rect at top scrollYDelta -= (listUnfadedTop - rect.top); } // make sure we aren't scrolling any further than the top our children int top = getChildAt(0).getTop(); int deltaToTop = top - listUnfadedTop; scrollYDelta = Math.max(scrollYDelta, deltaToTop); } final boolean scroll = scrollYDelta != 0; if (scroll) { scrollListItemsBy(-scrollYDelta); positionSelector(INVALID_POSITION, child); mSelectedTop = child.getTop(); invalidate(); } return scroll; } /** * {@inheritDoc} */ @Override void fillGap(boolean down) { final int count = getChildCount(); if (down) { int paddingTop = 0; if (mClipToPadding) { paddingTop = getListPaddingTop(); } final int startOffset = count > 0 ? getChildAt(count - 1).getBottom() + mDividerHeight : paddingTop; fillDown(mFirstPosition + count, startOffset); correctTooHigh(getChildCount()); } else { int paddingBottom = 0; if (mClipToPadding) { paddingBottom = getListPaddingBottom(); } final int startOffset = count > 0 ? getChildAt(0).getTop() - mDividerHeight : getHeight() - paddingBottom; fillUp(mFirstPosition - 1, startOffset); correctTooLow(getChildCount()); } } /** * Fills the list from pos down to the end of the list view. * * @param pos The first position to put in the list * * @param nextTop The location where the top of the item associated with pos * should be drawn * * @return The view that is currently selected, if it happens to be in the * range that we draw. */ private View fillDown(int pos, int nextTop) { View selectedView = null; int end = (getBottom() - getTop()); if (mClipToPadding) { end -= mListPadding.bottom; } while (nextTop < end && pos < mItemCount) { // is this the selected item? boolean selected = pos == mSelectedPosition; View child = makeAndAddView(pos, nextTop, true, mListPadding.left, selected); nextTop = child.getBottom() + mDividerHeight; if (selected) { selectedView = child; } pos++; } // FIXME removed bacause we do not need RemoteViews (j.m.) // setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); return selectedView; } /** * Fills the list from pos up to the top of the list view. * * @param pos The first position to put in the list * * @param nextBottom The location where the bottom of the item associated * with pos should be drawn * * @return The view that is currently selected */ private View fillUp(int pos, int nextBottom) { View selectedView = null; int end = 0; if (mClipToPadding) { end = mListPadding.top; } while (nextBottom > end && pos >= 0) { // is this the selected item? boolean selected = pos == mSelectedPosition; View child = makeAndAddView(pos, nextBottom, false, mListPadding.left, selected); nextBottom = child.getTop() - mDividerHeight; if (selected) { selectedView = child; } pos--; } mFirstPosition = pos + 1; // FIXME removed bacause we do not need RemoteViews (j.m.) // setVisibleRangeHint(mFirstPosition, mFirstPosition + getChildCount() - 1); return selectedView; } /** * Fills the list from top to bottom, starting with mFirstPosition * * @param nextTop The location where the top of the first item should be * drawn * * @return The view that is currently selected */ private View fillFromTop(int nextTop) { mFirstPosition = Math.min(mFirstPosition, mSelectedPosition); mFirstPosition = Math.min(mFirstPosition, mItemCount - 1); if (mFirstPosition < 0) { mFirstPosition = 0; } return fillDown(mFirstPosition, nextTop); } /** * Put mSelectedPosition in the middle of the screen and then build up and * down from there. This method forces mSelectedPosition to the center. * * @param childrenTop Top of the area in which children can be drawn, as * measured in pixels * @param childrenBottom Bottom of the area in which children can be drawn, * as measured in pixels * @return Currently selected view */ private View fillFromMiddle(int childrenTop, int childrenBottom) { int height = childrenBottom - childrenTop; int position = reconcileSelectedPosition(); View sel = makeAndAddView(position, childrenTop, true, mListPadding.left, true); mFirstPosition = position; int selHeight = sel.getMeasuredHeight(); if (selHeight <= height) { sel.offsetTopAndBottom((height - selHeight) / 2); } fillAboveAndBelow(sel, position); if (!mStackFromBottom) { correctTooHigh(getChildCount()); } else { correctTooLow(getChildCount()); } return sel; } /** * Once the selected view as been placed, fill up the visible area above and * below it. * * @param sel The selected view * @param position The position corresponding to sel */ private void fillAboveAndBelow(View sel, int position) { final int dividerHeight = mDividerHeight; if (!mStackFromBottom) { fillUp(position - 1, sel.getTop() - dividerHeight); adjustViewsUpOrDown(); fillDown(position + 1, sel.getBottom() + dividerHeight); } else { fillDown(position + 1, sel.getBottom() + dividerHeight); adjustViewsUpOrDown(); fillUp(position - 1, sel.getTop() - dividerHeight); } } /** * Fills the grid based on positioning the new selection at a specific * location. The selection may be moved so that it does not intersect the * faded edges. The grid is then filled upwards and downwards from there. * * @param selectedTop Where the selected item should be * @param childrenTop Where to start drawing children * @param childrenBottom Last pixel where children can be drawn * @return The view that currently has selection */ private View fillFromSelection(int selectedTop, int childrenTop, int childrenBottom) { int fadingEdgeLength = getVerticalFadingEdgeLength(); final int selectedPosition = mSelectedPosition; View sel; final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, selectedPosition); final int bottomSelectionPixel = getBottomSelectionPixel(childrenBottom, fadingEdgeLength, selectedPosition); sel = makeAndAddView(selectedPosition, selectedTop, true, mListPadding.left, true); // Some of the newly selected item extends below the bottom of the list if (sel.getBottom() > bottomSelectionPixel) { // Find space available above the selection into which we can scroll // upwards final int spaceAbove = sel.getTop() - topSelectionPixel; // Find space required to bring the bottom of the selected item // fully into view final int spaceBelow = sel.getBottom() - bottomSelectionPixel; final int offset = Math.min(spaceAbove, spaceBelow); // Now offset the selected item to get it into view sel.offsetTopAndBottom(-offset); } else if (sel.getTop() < topSelectionPixel) { // Find space required to bring the top of the selected item fully // into view final int spaceAbove = topSelectionPixel - sel.getTop(); // Find space available below the selection into which we can scroll // downwards final int spaceBelow = bottomSelectionPixel - sel.getBottom(); final int offset = Math.min(spaceAbove, spaceBelow); // Offset the selected item to get it into view sel.offsetTopAndBottom(offset); } // Fill in views above and below fillAboveAndBelow(sel, selectedPosition); if (!mStackFromBottom) { correctTooHigh(getChildCount()); } else { correctTooLow(getChildCount()); } return sel; } /** * Calculate the bottom-most pixel we can draw the selection into * * @param childrenBottom Bottom pixel were children can be drawn * @param fadingEdgeLength Length of the fading edge in pixels, if present * @param selectedPosition The position that will be selected * @return The bottom-most pixel we can draw the selection into */ private int getBottomSelectionPixel(int childrenBottom, int fadingEdgeLength, int selectedPosition) { int bottomSelectionPixel = childrenBottom; if (selectedPosition != mItemCount - 1) { bottomSelectionPixel -= fadingEdgeLength; } return bottomSelectionPixel; } /** * Calculate the top-most pixel we can draw the selection into * * @param childrenTop Top pixel were children can be drawn * @param fadingEdgeLength Length of the fading edge in pixels, if present * @param selectedPosition The position that will be selected * @return The top-most pixel we can draw the selection into */ private int getTopSelectionPixel(int childrenTop, int fadingEdgeLength, int selectedPosition) { // first pixel we can draw the selection into int topSelectionPixel = childrenTop; if (selectedPosition > 0) { topSelectionPixel += fadingEdgeLength; } return topSelectionPixel; } /** * Smoothly scroll to the specified adapter position. The view will * scroll such that the indicated position is displayed. * @param position Scroll to this adapter position. */ //@android.view.RemotableViewMethod public void smoothScrollToPosition(int position) { super.smoothScrollToPosition(position); } /** * Smoothly scroll to the specified adapter position offset. The view will * scroll such that the indicated position is displayed. * @param offset The amount to offset from the adapter position to scroll to. */ //@android.view.RemotableViewMethod public void smoothScrollByOffset(int offset) { super.smoothScrollByOffset(offset); } /** * Fills the list based on positioning the new selection relative to the old * selection. The new selection will be placed at, above, or below the * location of the new selection depending on how the selection is moving. * The selection will then be pinned to the visible part of the screen, * excluding the edges that are faded. The list is then filled upwards and * downwards from there. * * @param oldSel The old selected view. Useful for trying to put the new * selection in the same place * @param newSel The view that is to become selected. Useful for trying to * put the new selection in the same place * @param delta Which way we are moving * @param childrenTop Where to start drawing children * @param childrenBottom Last pixel where children can be drawn * @return The view that currently has selection */ private View moveSelection(View oldSel, View newSel, int delta, int childrenTop, int childrenBottom) { int fadingEdgeLength = getVerticalFadingEdgeLength(); final int selectedPosition = mSelectedPosition; View sel; final int topSelectionPixel = getTopSelectionPixel(childrenTop, fadingEdgeLength, selectedPosition); final int bottomSelectionPixel = getBottomSelectionPixel(childrenTop, fadingEdgeLength, selectedPosition); if (delta > 0) { /* * Case 1: Scrolling down. */ /* * Before After * | | | | * +-------+ +-------+ * | A | | A | * | 1 | => +-------+ * +-------+ | B | * | B | | 2 | * +-------+ +-------+ * | | | | * * Try to keep the top of the previously selected item where it was. * oldSel = A * sel = B */ // Put oldSel (A) where it belongs oldSel = makeAndAddView(selectedPosition - 1, oldSel.getTop(), true, mListPadding.left, false); final int dividerHeight = mDividerHeight; // Now put the new selection (B) below that sel = makeAndAddView(selectedPosition, oldSel.getBottom() + dividerHeight, true, mListPadding.left, true); // Some of the newly selected item extends below the bottom of the list if (sel.getBottom() > bottomSelectionPixel) { // Find space available above the selection into which we can scroll upwards int spaceAbove = sel.getTop() - topSelectionPixel; // Find space required to bring the bottom of the selected item fully into view int spaceBelow = sel.getBottom() - bottomSelectionPixel; // Don't scroll more than half the width of the list int halfVerticalSpace = (childrenBottom - childrenTop) / 2; int offset = Math.min(spaceAbove, spaceBelow); offset = Math.min(offset, halfVerticalSpace); // We placed oldSel, so offset that item oldSel.offsetTopAndBottom(-offset); // Now offset the selected item to get it into view sel.offsetTopAndBottom(-offset); } // Fill in views above and below if (!mStackFromBottom) { fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); adjustViewsUpOrDown(); fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); } else { fillDown(mSelectedPosition + 1, sel.getBottom() + dividerHeight); adjustViewsUpOrDown(); fillUp(mSelectedPosition - 2, sel.getTop() - dividerHeight); } } else if (delta < 0) { /* * Case 2: Scrolling up. */ /* * Before After * | | | | * +-------+ +-------+ * | A | | A | * +-------+ => | 1 | * | B | +-------+ * | 2 | | B | * +-------+ +-------+ * | | | | * * Try to keep the top of the item about to become selected where it was. * newSel = A * olSel = B */ if (newSel != null) { // Try to position the top of newSel (A) where it was before it was selected sel = makeAndAddView(selectedPosition, newSel.getTop(), true, mListPadding.left, true); } else { // If (A) was not on screen and so did not have a view, position // it above the oldSel (B) sel = makeAndAddView(selectedPosition, oldSel.getTop(), false, mListPadding.left, true); } // Some of the newly selected item extends above the top of the list if (sel.getTop() < topSelectionPixel) { // Find space required to bring the top of the selected item fully into view int spaceAbove = topSelectionPixel - sel.getTop(); // Find space available below the selection into which we can scroll downwards int spaceBelow = bottomSelectionPixel - sel.getBottom(); // Don't scroll more than half the width of the list int halfVerticalSpace = (childrenBottom - childrenTop) / 2; int offset = Math.min(spaceAbove, spaceBelow); offset = Math.min(offset, halfVerticalSpace); // Offset the selected item to get it into view sel.offsetTopAndBottom(offset); } // Fill in views above and below fillAboveAndBelow(sel, selectedPosition); } else { int oldTop = oldSel.getTop(); /* * Case 3: Staying still */ sel = makeAndAddView(selectedPosition, oldTop, true, mListPadding.left, true); // We're staying still... if (oldTop < childrenTop) { // ... but the top of the old selection was off screen. // (This can happen if the data changes size out from under us) int newBottom = sel.getBottom(); if (newBottom < childrenTop + 20) { // Not enough visible -- bring it onscreen sel.offsetTopAndBottom(childrenTop - sel.getTop()); } } // Fill in views above and below fillAboveAndBelow(sel, selectedPosition); } return sel; } private class FocusSelector implements Runnable { private int mPosition; private int mPositionTop; public FocusSelector setup(int position, int top) { mPosition = position; mPositionTop = top; return this; } public void run() { setSelectionFromTop(mPosition, mPositionTop); } } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { if (getChildCount() > 0) { View focusedChild = getFocusedChild(); if (focusedChild != null) { final int childPosition = mFirstPosition + indexOfChild(focusedChild); final int childBottom = focusedChild.getBottom(); final int offset = Math.max(0, childBottom - (h - getPaddingTop())); final int top = focusedChild.getTop() - offset; if (mFocusSelector == null) { mFocusSelector = new FocusSelector(); } post(mFocusSelector.setup(childPosition, top)); } } super.onSizeChanged(w, h, oldw, oldh); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { // Sets up mListPadding super.onMeasure(widthMeasureSpec, heightMeasureSpec); int widthMode = MeasureSpec.getMode(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); int childWidth = 0; int childHeight = 0; int childState = 0; mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || heightMode == MeasureSpec.UNSPECIFIED)) { final View child = obtainView(0, mIsScrap); measureScrapChild(child, 0, widthMeasureSpec); childWidth = child.getMeasuredWidth(); childHeight = child.getMeasuredHeight(); childState = Compat.combineMeasuredStates(childState, Compat.getMeasuredState(child)); if (recycleOnMeasure() && mRecycler.shouldRecycleViewType(((LayoutParams) child.getLayoutParams()).viewType)) { mRecycler.addScrapView(child, -1); } } if (widthMode == MeasureSpec.UNSPECIFIED) { widthSize = mListPadding.left + mListPadding.right + childWidth + getVerticalScrollbarWidth(); } else { widthSize |= (childState & MEASURED_STATE_MASK); } if (heightMode == MeasureSpec.UNSPECIFIED) { heightSize = mListPadding.top + mListPadding.bottom + childHeight + getVerticalFadingEdgeLength() * 2; } if (heightMode == MeasureSpec.AT_MOST) { // TODO: after first layout we should maybe start at the first visible position, not 0 heightSize = measureHeightOfChildren(widthMeasureSpec, 0, NO_POSITION, heightSize, -1); } setMeasuredDimension(widthSize, heightSize); mWidthMeasureSpec = widthMeasureSpec; } private void measureScrapChild(View child, int position, int widthMeasureSpec) { LayoutParams p = (LayoutParams) child.getLayoutParams(); if (p == null) { p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); child.setLayoutParams(p); } p.viewType = mAdapter.getItemViewType(position); p.forceAdd = true; int childWidthSpec = ViewGroup.getChildMeasureSpec(widthMeasureSpec, mListPadding.left + mListPadding.right, p.width); int lpHeight = p.height; int childHeightSpec; if (lpHeight > 0) { childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); } else { childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); } child.measure(childWidthSpec, childHeightSpec); } /** * @return True to recycle the views used to measure this ListView in * UNSPECIFIED/AT_MOST modes, false otherwise. * @hide */ @ViewDebug.ExportedProperty(category = "list") protected boolean recycleOnMeasure() { return true; } /** * Measures the width of the given range of children (inclusive) and * returns the width with this ListView's padding and divider heights * included. If maxHeight is provided, the measuring will stop when the * current width reaches maxHeight. * * @param widthMeasureSpec The width measure spec to be given to a child's * {@link View#measure(int, int)}. * @param startPosition The position of the first child to be shown. * @param endPosition The (inclusive) position of the last child to be * shown. Specify {@link #NO_POSITION} if the last child should be * the last available child from the adapter. * @param maxHeight The maximum width that will be returned (if all the * children don't fit in this value, this value will be * returned). * @param disallowPartialChildPosition In general, whether the returned * width should only contain entire children. This is more * powerful--it is the first inclusive position at which partial * children will not be allowed. Example: it looks nice to have * at least 3 completely visible children, and in portrait this * will most likely fit; but in landscape there could be times * when even 2 children can not be completely shown, so a value * of 2 (remember, inclusive) would be good (assuming * startPosition is 0). * @return The width of this ListView with the given children. */ final int measureHeightOfChildren(int widthMeasureSpec, int startPosition, int endPosition, final int maxHeight, int disallowPartialChildPosition) { final ListAdapter adapter = mAdapter; if (adapter == null) { return mListPadding.top + mListPadding.bottom; } // Include the padding of the list int returnedHeight = mListPadding.top + mListPadding.bottom; final int dividerHeight = ((mDividerHeight > 0) && mDivider != null) ? mDividerHeight : 0; // The previous width value that was less than maxHeight and contained // no partial children int prevHeightWithoutPartialChild = 0; int i; View child; // mItemCount - 1 since endPosition parameter is inclusive endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; final AbsListView.RecycleBin recycleBin = mRecycler; final boolean recyle = recycleOnMeasure(); final boolean[] isScrap = mIsScrap; for (i = startPosition; i <= endPosition; ++i) { child = obtainView(i, isScrap); measureScrapChild(child, i, widthMeasureSpec); if (i > 0) { // Count the divider for all but one child returnedHeight += dividerHeight; } // Recycle the view before we possibly return from the method if (recyle && recycleBin.shouldRecycleViewType(((LayoutParams) child.getLayoutParams()).viewType)) { recycleBin.addScrapView(child, -1); } returnedHeight += child.getMeasuredHeight(); if (returnedHeight >= maxHeight) { // We went over, figure out which width to return. If returnedHeight > maxHeight, // then the i'th position did not fit completely. return (disallowPartialChildPosition >= 0) // Disallowing is enabled (> -1) && (i > disallowPartialChildPosition) // We've past the min pos && (prevHeightWithoutPartialChild > 0) // We have a prev width && (returnedHeight != maxHeight) // i'th child did not fit completely ? prevHeightWithoutPartialChild : maxHeight; } if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { prevHeightWithoutPartialChild = returnedHeight; } } // At this point, we went through the range of children, and they each // completely fit, so return the returnedHeight return returnedHeight; } @Override int findMotionRow(int y) { int childCount = getChildCount(); if (childCount > 0) { if (!mStackFromBottom) { for (int i = 0; i < childCount; i++) { View v = getChildAt(i); if (y <= v.getBottom()) { return mFirstPosition + i; } } } else { for (int i = childCount - 1; i >= 0; i--) { View v = getChildAt(i); if (y >= v.getTop()) { return mFirstPosition + i; } } } } return INVALID_POSITION; } /** * Put a specific item at a specific location on the screen and then build * up and down from there. * * @param position The reference view to use as the starting point * @param top Pixel offset from the top of this view to the top of the * reference view. * * @return The selected view, or null if the selected view is outside the * visible area. */ private View fillSpecific(int position, int top) { boolean tempIsSelected = position == mSelectedPosition; View temp = makeAndAddView(position, top, true, mListPadding.left, tempIsSelected); // Possibly changed again in fillUp if we add rows above this one. mFirstPosition = position; View above; View below; final int dividerHeight = mDividerHeight; if (!mStackFromBottom) { above = fillUp(position - 1, temp.getTop() - dividerHeight); // This will correct for the top of the first view not touching the top of the list adjustViewsUpOrDown(); below = fillDown(position + 1, temp.getBottom() + dividerHeight); int childCount = getChildCount(); if (childCount > 0) { correctTooHigh(childCount); } } else { below = fillDown(position + 1, temp.getBottom() + dividerHeight); // This will correct for the bottom of the last view not touching the bottom of the list adjustViewsUpOrDown(); above = fillUp(position - 1, temp.getTop() - dividerHeight); int childCount = getChildCount(); if (childCount > 0) { correctTooLow(childCount); } } if (tempIsSelected) { return temp; } else if (above != null) { return above; } else { return below; } } /** * Check if we have dragged the bottom of the list too high (we have pushed the * top element off the top of the screen when we did not need to). Correct by sliding * everything back down. * * @param childCount Number of children */ private void correctTooHigh(int childCount) { // First see if the last item is visible. If it is not, it is OK for the // top of the list to be pushed up. int lastPosition = mFirstPosition + childCount - 1; if (lastPosition == mItemCount - 1 && childCount > 0) { // Get the last child ... final View lastChild = getChildAt(childCount - 1); // ... and its bottom edge final int lastBottom = lastChild.getBottom(); // This is bottom of our drawable area final int end = (getBottom() - getTop()) - mListPadding.bottom; // This is how far the bottom edge of the last view is from the bottom of the // drawable area int bottomOffset = end - lastBottom; View firstChild = getChildAt(0); final int firstTop = firstChild.getTop(); // Make sure we are 1) Too high, and 2) Either there are more rows above the // first row or the first row is scrolled off the top of the drawable area if (bottomOffset > 0 && (mFirstPosition > 0 || firstTop < mListPadding.top)) { if (mFirstPosition == 0) { // Don't pull the top too far down bottomOffset = Math.min(bottomOffset, mListPadding.top - firstTop); } // Move everything down offsetChildrenTopAndBottomUnhide(bottomOffset); if (mFirstPosition > 0) { // Fill the gap that was opened above mFirstPosition with more rows, if // possible fillUp(mFirstPosition - 1, firstChild.getTop() - mDividerHeight); // Close up the remaining gap adjustViewsUpOrDown(); } } } } /** * Check if we have dragged the bottom of the list too low (we have pushed the * bottom element off the bottom of the screen when we did not need to). Correct by sliding * everything back up. * * @param childCount Number of children */ private void correctTooLow(int childCount) { // First see if the first item is visible. If it is not, it is OK for the // bottom of the list to be pushed down. if (mFirstPosition == 0 && childCount > 0) { // Get the first child ... final View firstChild = getChildAt(0); // ... and its top edge final int firstTop = firstChild.getTop(); // This is top of our drawable area final int start = mListPadding.top; // This is bottom of our drawable area final int end = (getBottom() - getTop()) - mListPadding.bottom; // This is how far the top edge of the first view is from the top of the // drawable area int topOffset = firstTop - start; View lastChild = getChildAt(childCount - 1); final int lastBottom = lastChild.getBottom(); int lastPosition = mFirstPosition + childCount - 1; // Make sure we are 1) Too low, and 2) Either there are more rows below the // last row or the last row is scrolled off the bottom of the drawable area if (topOffset > 0) { if (lastPosition < mItemCount - 1 || lastBottom > end) { if (lastPosition == mItemCount - 1) { // Don't pull the bottom too far up topOffset = Math.min(topOffset, lastBottom - end); } // Move everything up offsetChildrenTopAndBottomUnhide(-topOffset); if (lastPosition < mItemCount - 1) { // Fill the gap that was opened below the last position with more rows, if // possible fillDown(lastPosition + 1, lastChild.getBottom() + mDividerHeight); // Close up the remaining gap adjustViewsUpOrDown(); } } else if (lastPosition == mItemCount - 1) { adjustViewsUpOrDown(); } } } } @Override protected void layoutChildren() { final boolean blockLayoutRequests = mBlockLayoutRequests; if (!blockLayoutRequests) { mBlockLayoutRequests = true; } else { return; } try { super.layoutChildren(); invalidate(); if (mAdapter == null) { resetList(); invokeOnItemScrollListener(); return; } int childrenTop = mListPadding.top; int childrenBottom = getBottom() - getTop() - mListPadding.bottom; int childCount = getChildCount(); int index = 0; int delta = 0; View sel; View oldSel = null; View oldFirst = null; View newSel = null; View focusLayoutRestoreView = null; AccessibilityNodeInfo accessibilityFocusLayoutRestoreNode = null; View accessibilityFocusLayoutRestoreView = null; int accessibilityFocusPosition = INVALID_POSITION; // Remember stuff we will need down below switch (mLayoutMode) { case LAYOUT_SET_SELECTION: index = mNextSelectedPosition - mFirstPosition; if (index >= 0 && index < childCount) { newSel = getChildAt(index); } break; case LAYOUT_FORCE_TOP: case LAYOUT_FORCE_BOTTOM: case LAYOUT_SPECIFIC: case LAYOUT_SYNC: break; case LAYOUT_MOVE_SELECTION: default: // Remember the previously selected view index = mSelectedPosition - mFirstPosition; if (index >= 0 && index < childCount) { oldSel = getChildAt(index); } // Remember the previous first child oldFirst = getChildAt(0); if (mNextSelectedPosition >= 0) { delta = mNextSelectedPosition - mSelectedPosition; } // Caution: newSel might be null newSel = getChildAt(index + delta); } boolean dataChanged = mDataChanged; if (dataChanged) { handleDataChanged(); } // Handle the empty set by removing all views that are visible // and calling it a day if (mItemCount == 0) { resetList(); invokeOnItemScrollListener(); return; } else if (mItemCount != mAdapter.getCount()) { throw new IllegalStateException("The content of the adapter has changed but " + "ListView did not receive a notification. Make sure the content of " + "your adapter is not modified from a background thread, but only " + "from the UI thread. [in ListView(" + getId() + ", " + getClass() + ") with Adapter(" + mAdapter.getClass() + ")]"); } setSelectedPositionInt(mNextSelectedPosition); // Pull all children into the RecycleBin. // These views will be reused if possible final int firstPosition = mFirstPosition; final RecycleBin recycleBin = mRecycler; // reset the focus restoration View focusLayoutRestoreDirectChild = null; // Don't put header or footer views into the Recycler. Those are // already cached in mHeaderViews; if (dataChanged) { for (int i = 0; i < childCount; i++) { recycleBin.addScrapView(getChildAt(i), firstPosition + i); } } else { recycleBin.fillActiveViews(childCount, firstPosition); } // take focus back to us temporarily to avoid the eventual // call to clear focus when removing the focused child below // from messing things up when ViewAncestor assigns focus back // to someone else final View focusedChild = getFocusedChild(); if (focusedChild != null) { // TODO: in some cases focusedChild.getParent() == null // we can remember the focused view to restore after relayout if the // data hasn't changed, or if the focused position is a header or footer if (!dataChanged || isDirectChildHeaderOrFooter(focusedChild)) { focusLayoutRestoreDirectChild = focusedChild; // remember the specific view that had focus focusLayoutRestoreView = findFocus(); if (focusLayoutRestoreView != null) { // tell it we are going to mess with it focusLayoutRestoreView.onStartTemporaryDetach(); } } requestFocus(); } // TODO We can use those accessability methods, we just remove those (j.m.) // //Remember which child, if any, had accessibility focus. // final ViewRootImpl viewRootImpl = getViewRootImpl(); // if (viewRootImpl != null) { // final View accessFocusedView = viewRootImpl.getAccessibilityFocusedHost(); // if (accessFocusedView != null) { // final View accessFocusedChild = findAccessibilityFocusedChild( // accessFocusedView); // if (accessFocusedChild != null) { // if (!dataChanged || isDirectChildHeaderOrFooter(accessFocusedChild)) { // // If the views won't be changing, try to maintain // // focus on the current view host and (if // // applicable) its virtual view. // accessibilityFocusLayoutRestoreView = accessFocusedView; // accessibilityFocusLayoutRestoreNode = viewRootImpl // .getAccessibilityFocusedVirtualView(); // } else { // // Otherwise, try to maintain focus at the same // // position. // accessibilityFocusPosition = getPositionForView(accessFocusedChild); // } // } // } // } // Clear out old views detachAllViewsFromParent(); recycleBin.removeSkippedScrap(); switch (mLayoutMode) { case LAYOUT_SET_SELECTION: if (newSel != null) { sel = fillFromSelection(newSel.getTop(), childrenTop, childrenBottom); } else { sel = fillFromMiddle(childrenTop, childrenBottom); } break; case LAYOUT_SYNC: sel = fillSpecific(mSyncPosition, mSpecificTop); break; case LAYOUT_FORCE_BOTTOM: sel = fillUp(mItemCount - 1, childrenBottom); adjustViewsUpOrDown(); break; case LAYOUT_FORCE_TOP: mFirstPosition = 0; sel = fillFromTop(childrenTop); adjustViewsUpOrDown(); break; case LAYOUT_SPECIFIC: sel = fillSpecific(reconcileSelectedPosition(), mSpecificTop); break; case LAYOUT_MOVE_SELECTION: sel = moveSelection(oldSel, newSel, delta, childrenTop, childrenBottom); break; default: if (childCount == 0) { if (!mStackFromBottom) { final int position = lookForSelectablePosition(0, true); setSelectedPositionInt(position); sel = fillFromTop(childrenTop); } else { final int position = lookForSelectablePosition(mItemCount - 1, false); setSelectedPositionInt(position); sel = fillUp(mItemCount - 1, childrenBottom); } } else { if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { sel = fillSpecific(mSelectedPosition, oldSel == null ? childrenTop : oldSel.getTop()); } else if (mFirstPosition < mItemCount) { sel = fillSpecific(mFirstPosition, oldFirst == null ? childrenTop : oldFirst.getTop()); } else { sel = fillSpecific(0, childrenTop); } } break; } // Flush any cached views that did not get reused above recycleBin.scrapActiveViews(); if (sel != null) { // the current selected item should get focus if items // are focusable if (mItemsCanFocus && hasFocus() && !sel.hasFocus()) { final boolean focusWasTaken = (sel == focusLayoutRestoreDirectChild && focusLayoutRestoreView != null && focusLayoutRestoreView.requestFocus()) || sel.requestFocus(); if (!focusWasTaken) { // selected item didn't take focus, fine, but still want // to make sure something else outside of the selected view // has focus final View focused = getFocusedChild(); if (focused != null) { focused.clearFocus(); } positionSelector(INVALID_POSITION, sel); } else { sel.setSelected(false); mSelectorRect.setEmpty(); } } else { positionSelector(INVALID_POSITION, sel); } mSelectedTop = sel.getTop(); } else { if (mTouchMode > TOUCH_MODE_DOWN && mTouchMode < TOUCH_MODE_SCROLL) { View child = getChildAt(mMotionPosition - mFirstPosition); if (child != null) positionSelector(mMotionPosition, child); } else { mSelectedTop = 0; mSelectorRect.setEmpty(); } // even if there is not selected position, we may need to restore // focus (i.e. something focusable in touch mode) if (hasFocus() && focusLayoutRestoreView != null) { focusLayoutRestoreView.requestFocus(); } } // TODO We can use those accessability methods, we just remove those (j.m.) // // Attempt to restore accessibility focus. // if (accessibilityFocusLayoutRestoreNode != null) { // accessibilityFocusLayoutRestoreNode.performAction( // AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS); // } else if (accessibilityFocusLayoutRestoreView != null) { // accessibilityFocusLayoutRestoreView.requestAccessibilityFocus(); // } else if (accessibilityFocusPosition != INVALID_POSITION) { // // Bound the position within the visible children. // final int position = MathUtils.constrain( // (accessibilityFocusPosition - mFirstPosition), 0, (getChildCount() - 1)); // final View restoreView = getChildAt(position); // if (restoreView != null) { // restoreView.requestAccessibilityFocus(); // } // } // tell focus view we are done mucking with it, if it is still in // our view hierarchy. if (focusLayoutRestoreView != null && focusLayoutRestoreView.getWindowToken() != null) { focusLayoutRestoreView.onFinishTemporaryDetach(); } mLayoutMode = LAYOUT_NORMAL; mDataChanged = false; if (mPositionScrollAfterLayout != null) { post(mPositionScrollAfterLayout); mPositionScrollAfterLayout = null; } mNeedSync = false; setNextSelectedPositionInt(mSelectedPosition); updateScrollIndicators(); if (mItemCount > 0) { checkSelectionChanged(); } invokeOnItemScrollListener(); } finally { if (!blockLayoutRequests) { mBlockLayoutRequests = false; } } } /** * @param focusedView the view that has accessibility focus. * @return the direct child that contains accessibility focus. */ private View findAccessibilityFocusedChild(View focusedView) { ViewParent viewParent = focusedView.getParent(); while ((viewParent instanceof View) && (viewParent != this)) { focusedView = (View) viewParent; viewParent = viewParent.getParent(); } if (!(viewParent instanceof View)) { return null; } return focusedView; } /** * @param child a direct child of this list. * @return Whether child is a header or footer view. */ private boolean isDirectChildHeaderOrFooter(View child) { final ArrayList<FixedViewInfo> headers = mHeaderViewInfos; final int numHeaders = headers.size(); for (int i = 0; i < numHeaders; i++) { if (child == headers.get(i).view) { return true; } } final ArrayList<FixedViewInfo> footers = mFooterViewInfos; final int numFooters = footers.size(); for (int i = 0; i < numFooters; i++) { if (child == footers.get(i).view) { return true; } } return false; } /** * Obtain the view and add it to our list of children. The view can be made * fresh, converted from an unused view, or used as is if it was in the * recycle bin. * * @param position Logical position in the list * @param y Top or bottom edge of the view to add * @param flow If flow is true, align top edge to y. If false, align bottom * edge to y. * @param childrenLeft Left edge where children should be positioned * @param selected Is this position selected? * @return View that was added */ private View makeAndAddView(int position, int y, boolean flow, int childrenLeft, boolean selected) { View child; if (!mDataChanged) { // Try to use an existing view for this position child = mRecycler.getActiveView(position); if (child != null) { // Found it -- we're using an existing child // This just needs to be positioned setupChild(child, position, y, flow, childrenLeft, selected, true); return child; } } // Make a new view for this position, or convert an unused view if possible child = obtainView(position, mIsScrap); // This needs to be positioned and measured setupChild(child, position, y, flow, childrenLeft, selected, mIsScrap[0]); return child; } /** * Add a view as a child and make sure it is measured (if necessary) and * positioned properly. * * @param child The view to add * @param position The position of this child * @param y The y position relative to which this view will be positioned * @param flowDown If true, align top edge to y. If false, align bottom * edge to y. * @param childrenLeft Left edge where children should be positioned * @param selected Is this position selected? * @param recycled Has this view been pulled from the recycle bin? If so it * does not need to be remeasured. */ private void setupChild(View child, int position, int y, boolean flowDown, int childrenLeft, boolean selected, boolean recycled) { final boolean isSelected = selected && shouldShowSelector(); final boolean updateChildSelected = isSelected != child.isSelected(); final int mode = mTouchMode; final boolean isPressed = mode > TOUCH_MODE_DOWN && mode < TOUCH_MODE_SCROLL && mMotionPosition == position; final boolean updateChildPressed = isPressed != child.isPressed(); final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); // Respect layout params that are already in the view. Otherwise make some up... // noinspection unchecked AbsListView.LayoutParams p = (AbsListView.LayoutParams) child.getLayoutParams(); if (p == null) { p = (AbsListView.LayoutParams) generateDefaultLayoutParams(); } p.viewType = mAdapter.getItemViewType(position); if ((recycled && !p.forceAdd) || (p.recycledHeaderFooter && p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { attachViewToParent(child, flowDown ? -1 : 0, p); } else { p.forceAdd = false; if (p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER) { p.recycledHeaderFooter = true; } addViewInLayout(child, flowDown ? -1 : 0, p, true); } if (updateChildSelected) { child.setSelected(isSelected); } if (updateChildPressed) { child.setPressed(isPressed); } if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { if (child instanceof Checkable) { ((Checkable) child).setChecked(mCheckStates.get(position)); } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { child.setActivated(mCheckStates.get(position)); } } if (needToMeasure) { int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, mListPadding.left + mListPadding.right, p.width); int lpHeight = p.height; int childHeightSpec; if (lpHeight > 0) { childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); } else { childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); } child.measure(childWidthSpec, childHeightSpec); } else { cleanupLayoutState(child); } final int w = child.getMeasuredWidth(); final int h = child.getMeasuredHeight(); final int childTop = flowDown ? y : y - h; if (needToMeasure) { final int childRight = childrenLeft + w; final int childBottom = childTop + h; child.layout(childrenLeft, childTop, childRight, childBottom); } else { child.offsetLeftAndRight(childrenLeft - child.getLeft()); child.offsetTopAndBottom(childTop - child.getTop()); } if (mCachingStarted && !child.isDrawingCacheEnabled()) { child.setDrawingCacheEnabled(true); } if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB && recycled && (((AbsListView.LayoutParams) child.getLayoutParams()).scrappedFromPosition) != position) { Compat.jumpDrawablesToCurrentState(child); } } @Override protected boolean canAnimate() { return super.canAnimate() && mItemCount > 0; } /** * Sets the currently selected item. If in touch mode, the item will not be selected * but it will still be positioned appropriately. If the specified selection position * is less than 0, then the item at position 0 will be selected. * * @param position Index (starting at 0) of the data item to be selected. */ @Override public void setSelection(int position) { setSelectionFromTop(position, 0); } /** * Sets the selected item and positions the selection y pixels from the top edge * of the ListView. (If in touch mode, the item will not be selected but it will * still be positioned appropriately.) * * @param position Index (starting at 0) of the data item to be selected. * @param y The distance from the top edge of the ListView (plus padding) that the * item will be positioned. */ public void setSelectionFromTop(int position, int y) { if (mAdapter == null) { return; } if (!isInTouchMode()) { position = lookForSelectablePosition(position, true); if (position >= 0) { setNextSelectedPositionInt(position); } } else { mResurrectToPosition = position; } if (position >= 0) { mLayoutMode = LAYOUT_SPECIFIC; mSpecificTop = mListPadding.top + y; if (mNeedSync) { mSyncPosition = position; mSyncRowId = mAdapter.getItemId(position); } if (mPositionScroller != null) { mPositionScroller.stop(); } requestLayout(); } } /** * Makes the item at the supplied position selected. * * @param position the position of the item to select */ @Override void setSelectionInt(int position) { setNextSelectedPositionInt(position); boolean awakeScrollbars = false; final int selectedPosition = mSelectedPosition; if (selectedPosition >= 0) { if (position == selectedPosition - 1) { awakeScrollbars = true; } else if (position == selectedPosition + 1) { awakeScrollbars = true; } } if (mPositionScroller != null) { mPositionScroller.stop(); } layoutChildren(); if (awakeScrollbars) { awakenScrollBars(); } } /** * Find a position that can be selected (i.e., is not a separator). * * @param position The starting position to look at. * @param lookDown Whether to look down for other positions. * @return The next selectable position starting at position and then searching either up or * down. Returns {@link #INVALID_POSITION} if nothing can be found. */ @Override int lookForSelectablePosition(int position, boolean lookDown) { final ListAdapter adapter = mAdapter; if (adapter == null || isInTouchMode()) { return INVALID_POSITION; } final int count = adapter.getCount(); if (!mAreAllItemsSelectable) { if (lookDown) { position = Math.max(0, position); while (position < count && !adapter.isEnabled(position)) { position++; } } else { position = Math.min(position, count - 1); while (position >= 0 && !adapter.isEnabled(position)) { position--; } } if (position < 0 || position >= count) { return INVALID_POSITION; } return position; } else { if (position < 0 || position >= count) { return INVALID_POSITION; } return position; } } /** * setSelectionAfterHeaderView set the selection to be the first list item * after the header views. */ public void setSelectionAfterHeaderView() { final int count = mHeaderViewInfos.size(); if (count > 0) { mNextSelectedPosition = 0; return; } if (mAdapter != null) { setSelection(count); } else { mNextSelectedPosition = count; mLayoutMode = LAYOUT_SET_SELECTION; } } @Override public boolean dispatchKeyEvent(KeyEvent event) { // Dispatch in the normal way boolean handled = super.dispatchKeyEvent(event); if (!handled) { // If we didn't handle it... View focused = getFocusedChild(); if (focused != null && event.getAction() == KeyEvent.ACTION_DOWN) { // ... and our focused child didn't handle it // ... give it to ourselves so we can scroll if necessary handled = onKeyDown(event.getKeyCode(), event); } } return handled; } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { return commonKey(keyCode, 1, event); } @Override public boolean onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) { return commonKey(keyCode, repeatCount, event); } @Override public boolean onKeyUp(int keyCode, KeyEvent event) { return commonKey(keyCode, 1, event); } private boolean commonKey(int keyCode, int count, KeyEvent event) { if (mAdapter == null || !mIsAttached) { return false; } if (mDataChanged) { layoutChildren(); } boolean handled = false; int action = event.getAction(); if (action != KeyEvent.ACTION_UP) { switch (keyCode) { case KeyEvent.KEYCODE_DPAD_UP: if (KeyEventCompat.hasNoModifiers(event)) { handled = resurrectSelectionIfNeeded(); if (!handled) { while (count-- > 0) { if (arrowScroll(FOCUS_UP)) { handled = true; } else { break; } } } } else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_ALT_ON)) { handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); } break; case KeyEvent.KEYCODE_DPAD_DOWN: if (KeyEventCompat.hasNoModifiers(event)) { handled = resurrectSelectionIfNeeded(); if (!handled) { while (count-- > 0) { if (arrowScroll(FOCUS_DOWN)) { handled = true; } else { break; } } } } else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_ALT_ON)) { handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); } break; case KeyEvent.KEYCODE_DPAD_LEFT: if (KeyEventCompat.hasNoModifiers(event)) { handled = handleHorizontalFocusWithinListItem(View.FOCUS_LEFT); } break; case KeyEvent.KEYCODE_DPAD_RIGHT: if (KeyEventCompat.hasNoModifiers(event)) { handled = handleHorizontalFocusWithinListItem(View.FOCUS_RIGHT); } break; case KeyEvent.KEYCODE_DPAD_CENTER: case KeyEvent.KEYCODE_ENTER: if (KeyEventCompat.hasNoModifiers(event)) { handled = resurrectSelectionIfNeeded(); if (!handled && event.getRepeatCount() == 0 && getChildCount() > 0) { keyPressed(); handled = true; } } break; case KeyEvent.KEYCODE_SPACE: if (mPopup == null || !mPopup.isShowing()) { if (KeyEventCompat.hasNoModifiers(event)) { handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); } else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_SHIFT_ON)) { handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); } handled = true; } break; case KeyEvent.KEYCODE_PAGE_UP: if (KeyEventCompat.hasNoModifiers(event)) { handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_UP); } else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_ALT_ON)) { handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); } break; case KeyEvent.KEYCODE_PAGE_DOWN: if (KeyEventCompat.hasNoModifiers(event)) { handled = resurrectSelectionIfNeeded() || pageScroll(FOCUS_DOWN); } else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_ALT_ON)) { handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); } break; case KeyEvent.KEYCODE_MOVE_HOME: if (KeyEventCompat.hasNoModifiers(event)) { handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_UP); } break; case KeyEvent.KEYCODE_MOVE_END: if (KeyEventCompat.hasNoModifiers(event)) { handled = resurrectSelectionIfNeeded() || fullScroll(FOCUS_DOWN); } break; case KeyEvent.KEYCODE_TAB: // XXX Sometimes it is useful to be able to TAB through the items in // a ListView sequentially. Unfortunately this can create an // asymmetry in TAB navigation order unless the list selection // always reverts to the top or bottom when receiving TAB focus from // another widget. Leaving this behavior disabled for now but // perhaps it should be configurable (and more comprehensive). if (false) { if (KeyEventCompat.hasNoModifiers(event)) { handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_DOWN); } else if (KeyEventCompat.hasModifiers(event, KeyEvent.META_SHIFT_ON)) { handled = resurrectSelectionIfNeeded() || arrowScroll(FOCUS_UP); } } break; } } if (handled) { return true; } if (sendToTextFilter(keyCode, count, event)) { return true; } switch (action) { case KeyEvent.ACTION_DOWN: return super.onKeyDown(keyCode, event); case KeyEvent.ACTION_UP: return super.onKeyUp(keyCode, event); case KeyEvent.ACTION_MULTIPLE: return super.onKeyMultiple(keyCode, count, event); default: // shouldn't happen return false; } } /** * Scrolls up or down by the number of items currently present on screen. * * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} * @return whether selection was moved */ boolean pageScroll(int direction) { int nextPage = -1; boolean down = false; if (direction == FOCUS_UP) { nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); } else if (direction == FOCUS_DOWN) { nextPage = Math.min(mItemCount - 1, mSelectedPosition + getChildCount() - 1); down = true; } if (nextPage >= 0) { int position = lookForSelectablePosition(nextPage, down); if (position >= 0) { mLayoutMode = LAYOUT_SPECIFIC; mSpecificTop = getPaddingTop() + getVerticalFadingEdgeLength(); if (down && position > mItemCount - getChildCount()) { mLayoutMode = LAYOUT_FORCE_BOTTOM; } if (!down && position < getChildCount()) { mLayoutMode = LAYOUT_FORCE_TOP; } setSelectionInt(position); invokeOnItemScrollListener(); if (!awakenScrollBars()) { invalidate(); } return true; } } return false; } /** * Go to the last or first item if possible (not worrying about panning across or navigating * within the internal focus of the currently selected item.) * * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} * * @return whether selection was moved */ boolean fullScroll(int direction) { boolean moved = false; if (direction == FOCUS_UP) { if (mSelectedPosition != 0) { int position = lookForSelectablePosition(0, true); if (position >= 0) { mLayoutMode = LAYOUT_FORCE_TOP; setSelectionInt(position); invokeOnItemScrollListener(); } moved = true; } } else if (direction == FOCUS_DOWN) { if (mSelectedPosition < mItemCount - 1) { int position = lookForSelectablePosition(mItemCount - 1, true); if (position >= 0) { mLayoutMode = LAYOUT_FORCE_BOTTOM; setSelectionInt(position); invokeOnItemScrollListener(); } moved = true; } } if (moved && !awakenScrollBars()) { awakenScrollBars(); invalidate(); } return moved; } /** * To avoid horizontal focus searches changing the selected item, we * manually focus search within the selected item (as applicable), and * prevent focus from jumping to something within another item. * @param direction one of {View.FOCUS_LEFT, View.FOCUS_RIGHT} * @return Whether this consumes the key event. */ private boolean handleHorizontalFocusWithinListItem(int direction) { if (direction != View.FOCUS_LEFT && direction != View.FOCUS_RIGHT) { throw new IllegalArgumentException("direction must be one of" + " {View.FOCUS_LEFT, View.FOCUS_RIGHT}"); } final int numChildren = getChildCount(); if (mItemsCanFocus && numChildren > 0 && mSelectedPosition != INVALID_POSITION) { final View selectedView = getSelectedView(); if (selectedView != null && selectedView.hasFocus() && selectedView instanceof ViewGroup) { final View currentFocus = selectedView.findFocus(); final View nextFocus = FocusFinder.getInstance().findNextFocus((ViewGroup) selectedView, currentFocus, direction); if (nextFocus != null) { // do the math to get interesting rect in next focus' coordinates currentFocus.getFocusedRect(mTempRect); offsetDescendantRectToMyCoords(currentFocus, mTempRect); offsetRectIntoDescendantCoords(nextFocus, mTempRect); if (nextFocus.requestFocus(direction, mTempRect)) { return true; } } // we are blocking the key from being handled (by returning true) // if the global result is going to be some other view within this // list. this is to acheive the overall goal of having // horizontal d-pad navigation remain in the current item. final View globalNextFocus = FocusFinder.getInstance().findNextFocus((ViewGroup) getRootView(), currentFocus, direction); if (globalNextFocus != null) { return isViewAncestorOf(globalNextFocus, this); } } } return false; } /** * Scrolls to the next or previous item if possible. * * @param direction either {@link View#FOCUS_UP} or {@link View#FOCUS_DOWN} * * @return whether selection was moved */ boolean arrowScroll(int direction) { try { mInLayout = true; final boolean handled = arrowScrollImpl(direction); if (handled) { playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction)); } return handled; } finally { mInLayout = false; } } /** * Handle an arrow scroll going up or down. Take into account whether items are selectable, * whether there are focusable items etc. * * @param direction Either {@link android.view.View#FOCUS_UP} or {@link android.view.View#FOCUS_DOWN}. * @return Whether any scrolling, selection or focus change occured. */ private boolean arrowScrollImpl(int direction) { if (getChildCount() <= 0) { return false; } View selectedView = getSelectedView(); int selectedPos = mSelectedPosition; int nextSelectedPosition = (direction == View.FOCUS_DOWN) ? lookForSelectablePosition(selectedPos + 1, true) : lookForSelectablePosition(selectedPos - 1, false); int amountToScroll = amountToScroll(direction, nextSelectedPosition); // if we are moving focus, we may OVERRIDE the default behavior final ArrowScrollFocusResult focusResult = mItemsCanFocus ? arrowScrollFocused(direction) : null; if (focusResult != null) { nextSelectedPosition = focusResult.getSelectedPosition(); amountToScroll = focusResult.getAmountToScroll(); } boolean needToRedraw = focusResult != null; if (nextSelectedPosition != INVALID_POSITION) { handleNewSelectionChange(selectedView, direction, nextSelectedPosition, focusResult != null); setSelectedPositionInt(nextSelectedPosition); setNextSelectedPositionInt(nextSelectedPosition); selectedView = getSelectedView(); selectedPos = nextSelectedPosition; if (mItemsCanFocus && focusResult == null) { // there was no new view found to take focus, make sure we // don't leave focus with the old selection final View focused = getFocusedChild(); if (focused != null) { focused.clearFocus(); } } needToRedraw = true; checkSelectionChanged(); } if (amountToScroll > 0) { scrollListItemsBy((direction == View.FOCUS_UP) ? amountToScroll : -amountToScroll); needToRedraw = true; } // if we didn't find a new focusable, make sure any existing focused // item that was panned off screen gives up focus. if (mItemsCanFocus && (focusResult == null) && selectedView != null && selectedView.hasFocus()) { final View focused = selectedView.findFocus(); if (!isViewAncestorOf(focused, this) || distanceToView(focused) > 0) { focused.clearFocus(); } } // if the current selection is panned off, we need to remove the selection if (nextSelectedPosition == INVALID_POSITION && selectedView != null && !isViewAncestorOf(selectedView, this)) { selectedView = null; hideSelector(); // but we don't want to set the ressurect position (that would make subsequent // unhandled key events bring back the item we just scrolled off!) mResurrectToPosition = INVALID_POSITION; } if (needToRedraw) { if (selectedView != null) { positionSelector(selectedPos, selectedView); mSelectedTop = selectedView.getTop(); } if (!awakenScrollBars()) { invalidate(); } invokeOnItemScrollListener(); return true; } return false; } /** * When selection changes, it is possible that the previously selected or the * next selected item will change its size. If so, we need to offset some folks, * and re-layout the items as appropriate. * * @param selectedView The currently selected view (before changing selection). * should be <code>null</code> if there was no previous selection. * @param direction Either {@link android.view.View#FOCUS_UP} or * {@link android.view.View#FOCUS_DOWN}. * @param newSelectedPosition The position of the next selection. * @param newFocusAssigned whether new focus was assigned. This matters because * when something has focus, we don't want to show selection (ugh). */ private void handleNewSelectionChange(View selectedView, int direction, int newSelectedPosition, boolean newFocusAssigned) { if (newSelectedPosition == INVALID_POSITION) { throw new IllegalArgumentException("newSelectedPosition needs to be valid"); } // whether or not we are moving down or up, we want to preserve the // top of whatever view is on top: // - moving down: the view that had selection // - moving up: the view that is getting selection View topView; View bottomView; int topViewIndex, bottomViewIndex; boolean topSelected = false; final int selectedIndex = mSelectedPosition - mFirstPosition; final int nextSelectedIndex = newSelectedPosition - mFirstPosition; if (direction == View.FOCUS_UP) { topViewIndex = nextSelectedIndex; bottomViewIndex = selectedIndex; topView = getChildAt(topViewIndex); bottomView = selectedView; topSelected = true; } else { topViewIndex = selectedIndex; bottomViewIndex = nextSelectedIndex; topView = selectedView; bottomView = getChildAt(bottomViewIndex); } final int numChildren = getChildCount(); // start with top view: is it changing size? if (topView != null) { topView.setSelected(!newFocusAssigned && topSelected); measureAndAdjustDown(topView, topViewIndex, numChildren); } // is the bottom view changing size? if (bottomView != null) { bottomView.setSelected(!newFocusAssigned && !topSelected); measureAndAdjustDown(bottomView, bottomViewIndex, numChildren); } } /** * Re-measure a child, and if its width changes, lay it out preserving its * top, and adjust the children below it appropriately. * @param child The child * @param childIndex The view group index of the child. * @param numChildren The number of children in the view group. */ private void measureAndAdjustDown(View child, int childIndex, int numChildren) { int oldHeight = child.getHeight(); measureItem(child); if (child.getMeasuredHeight() != oldHeight) { // lay out the view, preserving its top relayoutMeasuredItem(child); // adjust views below appropriately final int heightDelta = child.getMeasuredHeight() - oldHeight; for (int i = childIndex + 1; i < numChildren; i++) { getChildAt(i).offsetTopAndBottom(heightDelta); } } } /** * Measure a particular list child. * TODO: unify with setUpChild. * @param child The child. */ private void measureItem(View child) { ViewGroup.LayoutParams p = child.getLayoutParams(); if (p == null) { p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); } int childWidthSpec = ViewGroup.getChildMeasureSpec(mWidthMeasureSpec, mListPadding.left + mListPadding.right, p.width); int lpHeight = p.height; int childHeightSpec; if (lpHeight > 0) { childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); } else { childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); } child.measure(childWidthSpec, childHeightSpec); } /** * Layout a child that has been measured, preserving its top position. * TODO: unify with setUpChild. * @param child The child. */ private void relayoutMeasuredItem(View child) { final int w = child.getMeasuredWidth(); final int h = child.getMeasuredHeight(); final int childLeft = mListPadding.left; final int childRight = childLeft + w; final int childTop = child.getTop(); final int childBottom = childTop + h; child.layout(childLeft, childTop, childRight, childBottom); } /** * @return The amount to preview next items when arrow srolling. */ private int getArrowScrollPreviewLength() { return Math.max(MIN_SCROLL_PREVIEW_PIXELS, getVerticalFadingEdgeLength()); } /** * Determine how much we need to scroll in order to get the next selected view * visible, with a fading edge showing below as applicable. The amount is * capped at {@link #getMaxScrollAmount()} . * * @param direction either {@link android.view.View#FOCUS_UP} or * {@link android.view.View#FOCUS_DOWN}. * @param nextSelectedPosition The position of the next selection, or * {@link #INVALID_POSITION} if there is no next selectable position * @return The amount to scroll. Note: this is always positive! Direction * needs to be taken into account when actually scrolling. */ private int amountToScroll(int direction, int nextSelectedPosition) { final int listBottom = getHeight() - mListPadding.bottom; final int listTop = mListPadding.top; int numChildren = getChildCount(); if (direction == View.FOCUS_DOWN) { int indexToMakeVisible = numChildren - 1; if (nextSelectedPosition != INVALID_POSITION) { indexToMakeVisible = nextSelectedPosition - mFirstPosition; } while (numChildren <= indexToMakeVisible) { // Child to view is not attached yet. addViewBelow(getChildAt(numChildren - 1), mFirstPosition + numChildren - 1); numChildren++; } final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; final View viewToMakeVisible = getChildAt(indexToMakeVisible); int goalBottom = listBottom; if (positionToMakeVisible < mItemCount - 1) { goalBottom -= getArrowScrollPreviewLength(); } if (viewToMakeVisible.getBottom() <= goalBottom) { // item is fully visible. return 0; } if (nextSelectedPosition != INVALID_POSITION && (goalBottom - viewToMakeVisible.getTop()) >= getMaxScrollAmount()) { // item already has enough of it visible, changing selection is good enough return 0; } int amountToScroll = (viewToMakeVisible.getBottom() - goalBottom); if ((mFirstPosition + numChildren) == mItemCount) { // last is last in list -> make sure we don't scroll past it final int max = getChildAt(numChildren - 1).getBottom() - listBottom; amountToScroll = Math.min(amountToScroll, max); } return Math.min(amountToScroll, getMaxScrollAmount()); } else { int indexToMakeVisible = 0; if (nextSelectedPosition != INVALID_POSITION) { indexToMakeVisible = nextSelectedPosition - mFirstPosition; } while (indexToMakeVisible < 0) { // Child to view is not attached yet. addViewAbove(getChildAt(0), mFirstPosition); mFirstPosition--; indexToMakeVisible = nextSelectedPosition - mFirstPosition; } final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; final View viewToMakeVisible = getChildAt(indexToMakeVisible); int goalTop = listTop; if (positionToMakeVisible > 0) { goalTop += getArrowScrollPreviewLength(); } if (viewToMakeVisible.getTop() >= goalTop) { // item is fully visible. return 0; } if (nextSelectedPosition != INVALID_POSITION && (viewToMakeVisible.getBottom() - goalTop) >= getMaxScrollAmount()) { // item already has enough of it visible, changing selection is good enough return 0; } int amountToScroll = (goalTop - viewToMakeVisible.getTop()); if (mFirstPosition == 0) { // first is first in list -> make sure we don't scroll past it final int max = listTop - getChildAt(0).getTop(); amountToScroll = Math.min(amountToScroll, max); } return Math.min(amountToScroll, getMaxScrollAmount()); } } /** * Holds results of focus aware arrow scrolling. */ static private class ArrowScrollFocusResult { private int mSelectedPosition; private int mAmountToScroll; /** * How {@link ListView#arrowScrollFocused} returns its values. */ void populate(int selectedPosition, int amountToScroll) { mSelectedPosition = selectedPosition; mAmountToScroll = amountToScroll; } public int getSelectedPosition() { return mSelectedPosition; } public int getAmountToScroll() { return mAmountToScroll; } } /** * @param direction either {@link android.view.View#FOCUS_UP} or * {@link android.view.View#FOCUS_DOWN}. * @return The position of the next selectable position of the views that * are currently visible, taking into account the fact that there might * be no selection. Returns {@link #INVALID_POSITION} if there is no * selectable view on screen in the given direction. */ private int lookForSelectablePositionOnScreen(int direction) { final int firstPosition = mFirstPosition; if (direction == View.FOCUS_DOWN) { int startPos = (mSelectedPosition != INVALID_POSITION) ? mSelectedPosition + 1 : firstPosition; if (startPos >= mAdapter.getCount()) { return INVALID_POSITION; } if (startPos < firstPosition) { startPos = firstPosition; } final int lastVisiblePos = getLastVisiblePosition(); final ListAdapter adapter = getAdapter(); for (int pos = startPos; pos <= lastVisiblePos; pos++) { if (adapter.isEnabled(pos) && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { return pos; } } } else { int last = firstPosition + getChildCount() - 1; int startPos = (mSelectedPosition != INVALID_POSITION) ? mSelectedPosition - 1 : firstPosition + getChildCount() - 1; if (startPos < 0 || startPos >= mAdapter.getCount()) { return INVALID_POSITION; } if (startPos > last) { startPos = last; } final ListAdapter adapter = getAdapter(); for (int pos = startPos; pos >= firstPosition; pos--) { if (adapter.isEnabled(pos) && getChildAt(pos - firstPosition).getVisibility() == View.VISIBLE) { return pos; } } } return INVALID_POSITION; } /** * Do an arrow scroll based on focus searching. If a new view is * given focus, return the selection delta and amount to scroll via * an {@link ArrowScrollFocusResult}, otherwise, return null. * * @param direction either {@link android.view.View#FOCUS_UP} or * {@link android.view.View#FOCUS_DOWN}. * @return The result if focus has changed, or <code>null</code>. */ private ArrowScrollFocusResult arrowScrollFocused(final int direction) { final View selectedView = getSelectedView(); View newFocus; if (selectedView != null && selectedView.hasFocus()) { View oldFocus = selectedView.findFocus(); newFocus = FocusFinder.getInstance().findNextFocus(this, oldFocus, direction); } else { if (direction == View.FOCUS_DOWN) { final boolean topFadingEdgeShowing = (mFirstPosition > 0); final int listTop = mListPadding.top + (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); final int ySearchPoint = (selectedView != null && selectedView.getTop() > listTop) ? selectedView.getTop() : listTop; mTempRect.set(0, ySearchPoint, 0, ySearchPoint); } else { final boolean bottomFadingEdgeShowing = (mFirstPosition + getChildCount() - 1) < mItemCount; final int listBottom = getHeight() - mListPadding.bottom - (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); final int ySearchPoint = (selectedView != null && selectedView.getBottom() < listBottom) ? selectedView.getBottom() : listBottom; mTempRect.set(0, ySearchPoint, 0, ySearchPoint); } newFocus = FocusFinder.getInstance().findNextFocusFromRect(this, mTempRect, direction); } if (newFocus != null) { final int positionOfNewFocus = positionOfNewFocus(newFocus); // if the focus change is in a different new position, make sure // we aren't jumping over another selectable position if (mSelectedPosition != INVALID_POSITION && positionOfNewFocus != mSelectedPosition) { final int selectablePosition = lookForSelectablePositionOnScreen(direction); if (selectablePosition != INVALID_POSITION && ((direction == View.FOCUS_DOWN && selectablePosition < positionOfNewFocus) || (direction == View.FOCUS_UP && selectablePosition > positionOfNewFocus))) { return null; } } int focusScroll = amountToScrollToNewFocus(direction, newFocus, positionOfNewFocus); final int maxScrollAmount = getMaxScrollAmount(); if (focusScroll < maxScrollAmount) { // not moving too far, safe to give next view focus newFocus.requestFocus(direction); mArrowScrollFocusResult.populate(positionOfNewFocus, focusScroll); return mArrowScrollFocusResult; } else if (distanceToView(newFocus) < maxScrollAmount) { // Case to consider: // too far to get entire next focusable on screen, but by going // max scroll amount, we are getting it at least partially in view, // so give it focus and scroll the max ammount. newFocus.requestFocus(direction); mArrowScrollFocusResult.populate(positionOfNewFocus, maxScrollAmount); return mArrowScrollFocusResult; } } return null; } /** * @param newFocus The view that would have focus. * @return the position that contains newFocus */ private int positionOfNewFocus(View newFocus) { final int numChildren = getChildCount(); for (int i = 0; i < numChildren; i++) { final View child = getChildAt(i); if (isViewAncestorOf(newFocus, child)) { return mFirstPosition + i; } } throw new IllegalArgumentException("newFocus is not a child of any of the" + " children of the list!"); } /** * Return true if child is an ancestor of parent, (or equal to the parent). */ private boolean isViewAncestorOf(View child, View parent) { if (child == parent) { return true; } final ViewParent theParent = child.getParent(); return (theParent instanceof ViewGroup) && isViewAncestorOf((View) theParent, parent); } /** * Determine how much we need to scroll in order to get newFocus in view. * @param direction either {@link android.view.View#FOCUS_UP} or * {@link android.view.View#FOCUS_DOWN}. * @param newFocus The view that would take focus. * @param positionOfNewFocus The position of the list item containing newFocus * @return The amount to scroll. Note: this is always positive! Direction * needs to be taken into account when actually scrolling. */ private int amountToScrollToNewFocus(int direction, View newFocus, int positionOfNewFocus) { int amountToScroll = 0; newFocus.getDrawingRect(mTempRect); offsetDescendantRectToMyCoords(newFocus, mTempRect); if (direction == View.FOCUS_UP) { if (mTempRect.top < mListPadding.top) { amountToScroll = mListPadding.top - mTempRect.top; if (positionOfNewFocus > 0) { amountToScroll += getArrowScrollPreviewLength(); } } } else { final int listBottom = getHeight() - mListPadding.bottom; if (mTempRect.bottom > listBottom) { amountToScroll = mTempRect.bottom - listBottom; if (positionOfNewFocus < mItemCount - 1) { amountToScroll += getArrowScrollPreviewLength(); } } } return amountToScroll; } /** * Determine the distance to the nearest edge of a view in a particular * direction. * * @param descendant A descendant of this list. * @return The distance, or 0 if the nearest edge is already on screen. */ private int distanceToView(View descendant) { int distance = 0; descendant.getDrawingRect(mTempRect); offsetDescendantRectToMyCoords(descendant, mTempRect); final int listBottom = getBottom() - getTop() - mListPadding.bottom; if (mTempRect.bottom < mListPadding.top) { distance = mListPadding.top - mTempRect.bottom; } else if (mTempRect.top > listBottom) { distance = mTempRect.top - listBottom; } return distance; } /** * Scroll the children by amount, adding a view at the end and removing * views that fall off as necessary. * * @param amount The amount (positive or negative) to scroll. */ private void scrollListItemsBy(int amount) { offsetChildrenTopAndBottomUnhide(amount); final int listBottom = getHeight() - mListPadding.bottom; final int listTop = mListPadding.top; final AbsListView.RecycleBin recycleBin = mRecycler; if (amount < 0) { // shifted items up // may need to pan views into the bottom space int numChildren = getChildCount(); View last = getChildAt(numChildren - 1); while (last.getBottom() < listBottom) { final int lastVisiblePosition = mFirstPosition + numChildren - 1; if (lastVisiblePosition < mItemCount - 1) { last = addViewBelow(last, lastVisiblePosition); numChildren++; } else { break; } } // may have brought in the last child of the list that is skinnier // than the fading edge, thereby leaving space at the end. need // to shift back if (last.getBottom() < listBottom) { offsetChildrenTopAndBottomUnhide(listBottom - last.getBottom()); } // top views may be panned off screen View first = getChildAt(0); while (first.getBottom() < listTop) { AbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { recycleBin.addScrapView(first, mFirstPosition); } detachViewFromParent(first); first = getChildAt(0); mFirstPosition++; } } else { // shifted items down View first = getChildAt(0); // may need to pan views into top while ((first.getTop() > listTop) && (mFirstPosition > 0)) { first = addViewAbove(first, mFirstPosition); mFirstPosition--; } // may have brought the very first child of the list in too far and // need to shift it back if (first.getTop() > listTop) { offsetChildrenTopAndBottomUnhide(listTop - first.getTop()); } int lastIndex = getChildCount() - 1; View last = getChildAt(lastIndex); // bottom view may be panned off screen while (last.getTop() > listBottom) { AbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { recycleBin.addScrapView(last, mFirstPosition + lastIndex); } detachViewFromParent(last); last = getChildAt(--lastIndex); } } } private View addViewAbove(View theView, int position) { int abovePosition = position - 1; View view = obtainView(abovePosition, mIsScrap); int edgeOfNewChild = theView.getTop() - mDividerHeight; setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.left, false, mIsScrap[0]); return view; } private View addViewBelow(View theView, int position) { int belowPosition = position + 1; View view = obtainView(belowPosition, mIsScrap); int edgeOfNewChild = theView.getBottom() + mDividerHeight; setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.left, false, mIsScrap[0]); return view; } /** * Indicates that the views created by the ListAdapter can contain focusable * items. * * @param itemsCanFocus true if items can get focus, false otherwise */ public void setItemsCanFocus(boolean itemsCanFocus) { mItemsCanFocus = itemsCanFocus; if (!itemsCanFocus) { setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS); } } /** * @return Whether the views created by the ListAdapter can contain focusable * items. */ public boolean getItemsCanFocus() { return mItemsCanFocus; } @Override public boolean isOpaque() { boolean retValue = (mCachingActive && mIsCacheColorOpaque && mDividerIsOpaque && hasOpaqueScrollbarsUnhide()) || super.isOpaque(); if (retValue) { // only return true if the list items cover the entire area of the view final int listTop = mListPadding != null ? mListPadding.top : getPaddingTop(); View first = getChildAt(0); if (first == null || first.getTop() > listTop) { return false; } final int listBottom = getHeight() - (mListPadding != null ? mListPadding.bottom : getPaddingBottom()); View last = getChildAt(getChildCount() - 1); if (last == null || last.getBottom() < listBottom) { return false; } } return retValue; } @Override public void setCacheColorHint(int color) { final boolean opaque = (color >>> 24) == 0xFF; mIsCacheColorOpaque = opaque; if (opaque) { if (mDividerPaint == null) { mDividerPaint = new Paint(); } mDividerPaint.setColor(color); } super.setCacheColorHint(color); } void drawOverscrollHeader(Canvas canvas, Drawable drawable, Rect bounds) { final int height = drawable.getMinimumHeight(); canvas.save(); canvas.clipRect(bounds); final int span = bounds.bottom - bounds.top; if (span < height) { bounds.top = bounds.bottom - height; } drawable.setBounds(bounds); drawable.draw(canvas); canvas.restore(); } void drawOverscrollFooter(Canvas canvas, Drawable drawable, Rect bounds) { final int height = drawable.getMinimumHeight(); canvas.save(); canvas.clipRect(bounds); final int span = bounds.bottom - bounds.top; if (span < height) { bounds.bottom = bounds.top + height; } drawable.setBounds(bounds); drawable.draw(canvas); canvas.restore(); } @Override protected void dispatchDraw(Canvas canvas) { if (mCachingStarted) { mCachingActive = true; } // Draw the dividers final int dividerHeight = mDividerHeight; final Drawable overscrollHeader = mOverScrollHeader; final Drawable overscrollFooter = mOverScrollFooter; final boolean drawOverscrollHeader = overscrollHeader != null; final boolean drawOverscrollFooter = overscrollFooter != null; final boolean drawDividers = dividerHeight > 0 && mDivider != null; if (drawDividers || drawOverscrollHeader || drawOverscrollFooter) { // Only modify the top and bottom in the loop, we set the left and right here final Rect bounds = mTempRect; bounds.left = getPaddingLeft(); bounds.right = getRight() - getLeft() - getPaddingRight(); final int count = getChildCount(); final int headerCount = mHeaderViewInfos.size(); final int itemCount = mItemCount; final int footerLimit = itemCount - mFooterViewInfos.size() - 1; final boolean headerDividers = mHeaderDividersEnabled; final boolean footerDividers = mFooterDividersEnabled; final int first = mFirstPosition; final boolean areAllItemsSelectable = mAreAllItemsSelectable; final ListAdapter adapter = mAdapter; // If the list is opaque *and* the background is not, we want to // fill a rect where the dividers would be for non-selectable items // If the list is opaque and the background is also opaque, we don't // need to draw anything since the background will do it for us final boolean fillForMissingDividers = isOpaque() && !super.isOpaque(); if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { mDividerPaint = new Paint(); mDividerPaint.setColor(getCacheColorHint()); } final Paint paint = mDividerPaint; int effectivePaddingTop = 0; int effectivePaddingBottom = 0; if (mClipToPadding) { effectivePaddingTop = mListPadding.top; effectivePaddingBottom = mListPadding.bottom; } final int viewBottom = getBottom(); final int viewTop = getTop(); final int scrollY = getScrollY(); final int listBottom = viewBottom - viewTop - effectivePaddingBottom + scrollY; if (!mStackFromBottom) { int bottom = 0; // Draw top divider or header for overscroll if (count > 0 && scrollY < 0) { if (drawOverscrollHeader) { bounds.bottom = 0; bounds.top = scrollY; drawOverscrollHeader(canvas, overscrollHeader, bounds); } else if (drawDividers) { bounds.bottom = 0; bounds.top = -dividerHeight; drawDivider(canvas, bounds, -1); } } for (int i = 0; i < count; i++) { if ((headerDividers || first + i >= headerCount) && (footerDividers || first + i < footerLimit)) { View child = getChildAt(i); bottom = child.getBottom(); // Don't draw dividers next to items that are not enabled if (drawDividers && (bottom < listBottom && !(drawOverscrollFooter && i == count - 1))) { if ((areAllItemsSelectable || (adapter.isEnabled(first + i) && (i == count - 1 || adapter.isEnabled(first + i + 1))))) { bounds.top = bottom; bounds.bottom = bottom + dividerHeight; drawDivider(canvas, bounds, i); } else if (fillForMissingDividers) { bounds.top = bottom; bounds.bottom = bottom + dividerHeight; canvas.drawRect(bounds, paint); } } } } final int overFooterBottom = viewBottom + scrollY; if (drawOverscrollFooter && first + count == itemCount && overFooterBottom > bottom) { bounds.top = bottom; bounds.bottom = overFooterBottom; drawOverscrollFooter(canvas, overscrollFooter, bounds); } } else { int top; if (count > 0 && drawOverscrollHeader) { bounds.top = scrollY; bounds.bottom = getChildAt(0).getTop(); drawOverscrollHeader(canvas, overscrollHeader, bounds); } final int start = drawOverscrollHeader ? 1 : 0; for (int i = start; i < count; i++) { if ((headerDividers || first + i >= headerCount) && (footerDividers || first + i < footerLimit)) { View child = getChildAt(i); top = child.getTop(); // Don't draw dividers next to items that are not enabled if (top > effectivePaddingTop) { if ((areAllItemsSelectable || (adapter.isEnabled(first + i) && (i == count - 1 || adapter.isEnabled(first + i + 1))))) { bounds.top = top - dividerHeight; bounds.bottom = top; // Give the method the child ABOVE the divider, so we // subtract one from our child // position. Give -1 when there is no child above the // divider. drawDivider(canvas, bounds, i - 1); } else if (fillForMissingDividers) { bounds.top = top - dividerHeight; bounds.bottom = top; canvas.drawRect(bounds, paint); } } } } if (count > 0 && scrollY > 0) { if (drawOverscrollFooter) { final int absListBottom = viewBottom; bounds.top = absListBottom; bounds.bottom = absListBottom + scrollY; drawOverscrollFooter(canvas, overscrollFooter, bounds); } else if (drawDividers) { bounds.top = listBottom; bounds.bottom = listBottom + dividerHeight; drawDivider(canvas, bounds, -1); } } } } // Draw the indicators (these should be drawn above the dividers) and children super.dispatchDraw(canvas); } @Override protected boolean drawChild(Canvas canvas, View child, long drawingTime) { boolean more = super.drawChild(canvas, child, drawingTime); // TODO do not have access to cahing... try to ignore (j.m.) // if (mCachingActive && child.mCachingFailed) { if (mCachingActive) { mCachingActive = false; } return more; } /** * Draws a divider for the given child in the given bounds. * * @param canvas The canvas to draw to. * @param bounds The bounds of the divider. * @param childIndex The index of child (of the View) above the divider. * This will be -1 if there is no child above the divider to be * drawn. */ void drawDivider(Canvas canvas, Rect bounds, int childIndex) { // This widget draws the same divider for all children final Drawable divider = mDivider; divider.setBounds(bounds); divider.draw(canvas); } /** * Returns the drawable that will be drawn between each item in the list. * * @return the current drawable drawn between list elements */ public Drawable getDivider() { return mDivider; } /** * Sets the drawable that will be drawn between each item in the list. If the drawable does * not have an intrinsic width, you should also call {@link #setDividerHeight(int)} * * @param divider The drawable to use. */ public void setDivider(Drawable divider) { if (divider != null) { mDividerHeight = divider.getIntrinsicHeight(); } else { mDividerHeight = 0; } mDivider = divider; mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; requestLayout(); invalidate(); } /** * @return Returns the width of the divider that will be drawn between each item in the list. */ public int getDividerHeight() { return mDividerHeight; } /** * Sets the width of the divider that will be drawn between each item in the list. Calling * this will override the intrinsic width as set by {@link #setDivider(Drawable)} * * @param height The new width of the divider in pixels. */ public void setDividerHeight(int height) { mDividerHeight = height; requestLayout(); invalidate(); } /** * Enables or disables the drawing of the divider for header views. * * @param headerDividersEnabled True to draw the headers, false otherwise. * * @see #setFooterDividersEnabled(boolean) * @see #addHeaderView(android.view.View) */ public void setHeaderDividersEnabled(boolean headerDividersEnabled) { mHeaderDividersEnabled = headerDividersEnabled; invalidate(); } /** * Enables or disables the drawing of the divider for footer views. * * @param footerDividersEnabled True to draw the footers, false otherwise. * * @see #setHeaderDividersEnabled(boolean) * @see #addFooterView(android.view.View) */ public void setFooterDividersEnabled(boolean footerDividersEnabled) { mFooterDividersEnabled = footerDividersEnabled; invalidate(); } /** * Sets the drawable that will be drawn above all other list content. * This area can become visible when the user overscrolls the list. * * @param header The drawable to use */ public void setOverscrollHeader(Drawable header) { mOverScrollHeader = header; final int scrollY = getScrollY(); if (scrollY < 0) { invalidate(); } } /** * @return The drawable that will be drawn above all other list content */ public Drawable getOverscrollHeader() { return mOverScrollHeader; } /** * Sets the drawable that will be drawn below all other list content. * This area can become visible when the user overscrolls the list, * or when the list's content does not fully fill the container area. * * @param footer The drawable to use */ public void setOverscrollFooter(Drawable footer) { mOverScrollFooter = footer; invalidate(); } /** * @return The drawable that will be drawn below all other list content */ public Drawable getOverscrollFooter() { return mOverScrollFooter; } @Override protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); final ListAdapter adapter = mAdapter; int closetChildIndex = -1; int closestChildTop = 0; if (adapter != null && gainFocus && previouslyFocusedRect != null) { final int scrollX = getScrollX(); final int scrollY = getScrollY(); previouslyFocusedRect.offset(scrollX, scrollY); // Don't cache the result of getChildCount or mFirstPosition here, // it could change in layoutChildren. if (adapter.getCount() < getChildCount() + mFirstPosition) { mLayoutMode = LAYOUT_NORMAL; layoutChildren(); } // figure out which item should be selected based on previously // focused rect Rect otherRect = mTempRect; int minDistance = Integer.MAX_VALUE; final int childCount = getChildCount(); final int firstPosition = mFirstPosition; for (int i = 0; i < childCount; i++) { // only consider selectable views if (!adapter.isEnabled(firstPosition + i)) { continue; } View other = getChildAt(i); other.getDrawingRect(otherRect); offsetDescendantRectToMyCoords(other, otherRect); int distance = getDistance(previouslyFocusedRect, otherRect, direction); if (distance < minDistance) { minDistance = distance; closetChildIndex = i; closestChildTop = other.getTop(); } } } if (closetChildIndex >= 0) { setSelectionFromTop(closetChildIndex + mFirstPosition, closestChildTop); } else { requestLayout(); } } /* * (non-Javadoc) * * Children specified in XML are assumed to be header views. After we have * parsed them move them out of the children list and into mHeaderViews. */ @Override protected void onFinishInflate() { super.onFinishInflate(); int count = getChildCount(); if (count > 0) { for (int i = 0; i < count; ++i) { addHeaderView(getChildAt(i)); } removeAllViews(); } } // TODO Probably we do not need this (j.m.) // /* (non-Javadoc) // * @see android.view.View#findViewById(int) // * First look in our children, then in any header and footer views that may be scrolled off. // */ // @Override // protected View findViewTraversal(int id) { // View v = super.findViewTraversal(id); // if (v == null) { // v = findViewInHeadersOrFooters(mHeaderViewInfos, id); // if (v != null) { // return v; // } // v = findViewInHeadersOrFooters(mFooterViewInfos, id); // if (v != null) { // return v; // } // } // return v; // } // // /* (non-Javadoc) // * // * Look in the passed in list of headers or footers for the view. // */ // View findViewInHeadersOrFooters(ArrayList<FixedViewInfo> where, int id) { // if (where != null) { // int len = where.size(); // View v; // // for (int i = 0; i < len; i++) { // v = where.get(i).view; // // if (!v.isRootNamespace()) { // v = v.findViewById(id); // // if (v != null) { // return v; // } // } // } // } // return null; // } // // /* (non-Javadoc) // * @see android.view.View#findViewWithTag(Object) // * First look in our children, then in any header and footer views that may be scrolled off. // */ // @Override // protected View findViewWithTagTraversal(Object tag) { // View v; // v = super.findViewWithTagTraversal(tag); // if (v == null) { // v = findViewWithTagInHeadersOrFooters(mHeaderViewInfos, tag); // if (v != null) { // return v; // } // // v = findViewWithTagInHeadersOrFooters(mFooterViewInfos, tag); // if (v != null) { // return v; // } // } // return v; // } // // /* (non-Javadoc) // * // * Look in the passed in list of headers or footers for the view with the tag. // */ // View findViewWithTagInHeadersOrFooters(ArrayList<FixedViewInfo> where, Object tag) { // if (where != null) { // int len = where.size(); // View v; // // for (int i = 0; i < len; i++) { // v = where.get(i).view; // // if (!v.isRootNamespace()) { // v = v.findViewWithTag(tag); // // if (v != null) { // return v; // } // } // } // } // return null; // } // // /** // * @hide // * @see android.view.View#findViewByPredicate(Predicate) // * First look in our children, then in any header and footer views that may be scrolled off. // */ // @Override // protected View findViewByPredicateTraversal(Predicate<View> predicate, View childToSkip) { // View v; // v = super.findViewByPredicateTraversal(predicate, childToSkip); // if (v == null) { // v = findViewByPredicateInHeadersOrFooters(mHeaderViewInfos, predicate, childToSkip); // if (v != null) { // return v; // } // // v = findViewByPredicateInHeadersOrFooters(mFooterViewInfos, predicate, childToSkip); // if (v != null) { // return v; // } // } // return v; // } // // /* (non-Javadoc) // * // * Look in the passed in list of headers or footers for the first view that matches // * the predicate. // */ // View findViewByPredicateInHeadersOrFooters(ArrayList<FixedViewInfo> where, // Predicate<View> predicate, View childToSkip) { // if (where != null) { // int len = where.size(); // View v; // // for (int i = 0; i < len; i++) { // v = where.get(i).view; // // if (v != childToSkip && !v.isRootNamespace()) { // v = v.findViewByPredicate(predicate); // // if (v != null) { // return v; // } // } // } // } // return null; // } /** * Returns the set of checked items ids. The result is only valid if the * choice mode has not been set to {@link #CHOICE_MODE_NONE}. * * @return A new array which contains the id of each checked item in the * list. * * @deprecated Use {@link #getCheckedItemIds()} instead. */ @Deprecated public long[] getCheckItemIds() { // Use new behavior that correctly handles stable ID mapping. if (mAdapter != null && mAdapter.hasStableIds()) { return getCheckedItemIds(); } // Old behavior was buggy, but would sort of work for adapters without stable IDs. // Fall back to it to support legacy apps. if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null && mAdapter != null) { final SparseBooleanArray states = mCheckStates; final int count = states.size(); final long[] ids = new long[count]; final ListAdapter adapter = mAdapter; int checkedCount = 0; for (int i = 0; i < count; i++) { if (states.valueAt(i)) { ids[checkedCount++] = adapter.getItemId(states.keyAt(i)); } } // Trim array if needed. mCheckStates may contain false values // resulting in checkedCount being smaller than count. if (checkedCount == count) { return ids; } else { final long[] result = new long[checkedCount]; System.arraycopy(ids, 0, result, 0, checkedCount); return result; } } return new long[0]; } @Override public void onInitializeAccessibilityEvent(AccessibilityEvent event) { super.onInitializeAccessibilityEvent(event); event.setClassName(ListView.class.getName()); } @TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH) @Override public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { super.onInitializeAccessibilityNodeInfo(info); info.setClassName(ListView.class.getName()); } }