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 org.bangbang.support.v4.widget; import java.util.ArrayList; import org.bangbang.android.support.v4.R; 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.ColorDrawable; import android.graphics.drawable.Drawable; import android.os.Parcel; import android.os.Parcelable; import android.util.AttributeSet; import android.util.Log; import android.util.SparseBooleanArray; import android.view.FocusFinder; import android.view.KeyEvent; import android.view.MotionEvent; 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.widget.ArrayAdapter; import android.widget.Checkable; import android.widget.HeaderViewListAdapter; import android.widget.ListAdapter; import android.widget.WrapperListAdapter; /* * Implementation Notes: * * Some terminology: * * index - index of the items that are currently visible * position - index of the items in the cursor */ /** * copied from * https://raw.github.com/android/platform_frameworks_base/donut-release/core/java/android/widget/ListView.java * * bysong@tudou.com */ /** * A view that shows items in a vertically scrolling list. The items * come from the {@link ListAdapter} associated with this view. * * @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_choiceMode * @attr ref android.R.styleable#ListView_headerDividersEnabled * @attr ref android.R.styleable#ListView_footerDividersEnabled */ public class HListView extends HAbsListView { private static final String TAG = HListView.class.getSimpleName(); private static final boolean DEBUG_MEASURE = true; /** * Used to indicate a no preference for a position type. */ static final int NO_POSITION = -1; /** * Normal list that does not indicate choices */ public static final int CHOICE_MODE_NONE = 0; /** * The list allows up to one choice */ public static final int CHOICE_MODE_SINGLE = 1; /** * The list allows multiple choices */ public static final int CHOICE_MODE_MULTIPLE = 2; /** * When arrow scrolling, ListView will never scroll more than this factor * times the height 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 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 = new ArrayList<FixedViewInfo>();//Lists.newArrayList(); private ArrayList<FixedViewInfo> mFooterViewInfos = new ArrayList<FixedViewInfo>();//Lists.newArrayList(); Drawable mDivider; int mDividerWidth; private boolean mIsCacheColorOpaque; private boolean mDividerIsOpaque; private boolean mClipDivider; private boolean mHeaderDividersEnabled; private boolean mFooterDividersEnabled; private boolean mAreAllItemsSelectable = true; private boolean mItemsCanFocus = false; private int mChoiceMode = CHOICE_MODE_NONE; private SparseBooleanArray mCheckStates; // 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 ArrowScrollFocusResult mArrowScrollFocusResult = new ArrowScrollFocusResult(); public HListView(Context context) { this(context, null); } public HListView(Context context, AttributeSet attrs) { this(context, attrs, 0/*com.android.internal.R.attr.listViewStyle*/); } public HListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); TypedArray a = context.obtainStyledAttributes(attrs, /*com.android.internal.*/R.styleable.HListView, defStyle, 0); CharSequence[] entries = a.getTextArray(/*com.android.internal.*/R.styleable.HListView_entries); if (entries != null) { setAdapter(new ArrayAdapter<CharSequence>(context, /*com.android.internal.*/android.R.layout.simple_list_item_1, entries)); } final Drawable d = a.getDrawable(/*com.android.internal.*/R.styleable.HListView_divider); if (d != null) { // If a divider is specified use its intrinsic height for divider height setDivider(d); } // Use the height specified, zero being the default final int dividerHeight = a .getDimensionPixelSize(/*com.android.internal.*/R.styleable.HListView_dividerWidth, 0); if (dividerHeight != 0) { setDividerHeight(dividerHeight); } setChoiceMode(a.getInt(R.styleable.HListView_choiceMode, CHOICE_MODE_NONE)); mHeaderDividersEnabled = a.getBoolean(R.styleable.HListView_headerDividersEnabled, true); mFooterDividersEnabled = a.getBoolean(R.styleable.HListView_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 * (getRight() - getLeft())); } /** * 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.getLeft() - mListPadding.left; if (mFirstPosition != 0) { // It's OK to have some space above the first item if it is // part of the vertical spacing delta -= mDividerWidth; } 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.getRight() - (getWidth() - mListPadding.right); if (mFirstPosition + childCount < mItemCount) { // It's OK to have some space below the last item if it is // part of the vertical spacing delta += mDividerWidth; } if (delta > 0) { delta = 0; } } if (delta != 0) { // offsetChildrenTopAndBottom(-delta); ViewCompat.offsetChildrenLeftAndRight(this, -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 that will also account for header * 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) { 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); } /** * 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 that will also account for header * 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 (((HeaderViewListAdapter) mAdapter).removeHeader(v)) { 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 that will also account for header * 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) { 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 (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 that will also account for header 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 (((HeaderViewListAdapter) mAdapter).removeFooter(v)) { 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 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 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 (null != mAdapter) { 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; 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(); } if (mCheckStates != null) { mCheckStates.clear(); } 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(child); mSelectedTop = child.getTop(); invalidate(); } return scroll; } /** * {@inheritDoc} */ @Override void fillGap(boolean down) { final int count = getChildCount(); if (down) { final int startOffset = count > 0 ? getChildAt(count - 1).getRight() + mDividerWidth : getListPaddingLeft(); fillDown(mFirstPosition + count, startOffset); correctTooHigh(getChildCount()); } else { final int startOffset = count > 0 ? getChildAt(0).getLeft() - mDividerWidth : getWidth() - getListPaddingRight(); 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 nextLeft 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 nextLeft) { View selectedView = null; int end = (getRight() - getLeft()) - mListPadding.right; while (nextLeft < end && pos < mItemCount) { // is this the selected item? boolean selected = pos == mSelectedPosition; View child = makeAndAddView(pos, nextLeft, true, mListPadding.top, selected); nextLeft = child.getRight() + mDividerWidth; if (selected) { selectedView = child; } pos++; } 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 nextRight 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 nextRight) { View selectedView = null; int end = mListPadding.left; while (nextRight > end && pos >= 0) { // is this the selected item? boolean selected = pos == mSelectedPosition; View child = makeAndAddView(pos, nextRight, false, mListPadding.top, selected); nextRight = child.getLeft() - mDividerWidth; if (selected) { selectedView = child; } pos--; } mFirstPosition = pos + 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 childrenLeft Top of the area in which children can be drawn, as * measured in pixels * @param childrenRight Bottom of the area in which children can be drawn, * as measured in pixels * @return Currently selected view */ private View fillFromMiddle(int childrenLeft, int childrenRight) { int width = childrenRight - childrenLeft; int position = reconcileSelectedPosition(); View sel = makeAndAddView(position, childrenLeft, true, mListPadding.top, true); mFirstPosition = position; int selHeight = sel.getMeasuredWidth(); if (selHeight <= width) { sel.offsetLeftAndRight((width - 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 dividerWidth = mDividerWidth; if (!mStackFromBottom) { fillUp(position - 1, sel.getLeft() - dividerWidth); adjustViewsUpOrDown(); fillDown(position + 1, sel.getRight() + dividerWidth); } else { fillDown(position + 1, sel.getRight() + dividerWidth); adjustViewsUpOrDown(); fillUp(position - 1, sel.getLeft() - dividerWidth); } } /** * 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.top, true); // Some of the newly selected item extends below the bottom of the list if (sel.getRight() > bottomSelectionPixel) { // Find space available above the selection into which we can scroll // upwards final int spaceAbove = sel.getLeft() - topSelectionPixel; // Find space required to bring the bottom of the selected item // fully into view final int spaceBelow = sel.getRight() - bottomSelectionPixel; final int offset = Math.min(spaceAbove, spaceBelow); // Now offset the selected item to get it into view // sel.offsetTopAndBottom(-offset); sel.offsetLeftAndRight(-offset); } else if (sel.getLeft() < topSelectionPixel) { // Find space required to bring the top of the selected item fully // into view final int spaceAbove = topSelectionPixel - sel.getLeft(); // Find space available below the selection into which we can scroll // downwards final int spaceBelow = bottomSelectionPixel - sel.getRight(); final int offset = Math.min(spaceAbove, spaceBelow); // Offset the selected item to get it into view // sel.offsetTopAndBottom(offset); sel.offsetLeftAndRight(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; } /** * 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 childrenLeft Where to start drawing children * @param childrenRight Last pixel where children can be drawn * @return The view that currently has selection */ private View moveSelection(View oldSel, View newSel, int delta, int childrenLeft, int childrenRight) { int fadingEdgeLength = getVerticalFadingEdgeLength(); final int selectedPosition = mSelectedPosition; View sel; final int topSelectionPixel = getTopSelectionPixel(childrenLeft, fadingEdgeLength, selectedPosition); final int bottomSelectionPixel = getBottomSelectionPixel(childrenLeft, 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.getLeft(), true, mListPadding.top, false); final int dividerWidth = mDividerWidth; // Now put the new selection (B) below that sel = makeAndAddView(selectedPosition, oldSel.getRight() + dividerWidth, true, mListPadding.top, true); // Some of the newly selected item extends below the bottom of the list if (sel.getRight() > bottomSelectionPixel) { // Find space available above the selection into which we can scroll upwards int spaceAbove = sel.getLeft() - topSelectionPixel; // Find space required to bring the bottom of the selected item fully into view int spaceBelow = sel.getRight() - bottomSelectionPixel; // Don't scroll more than half the height of the list int halfVerticalSpace = (childrenRight - childrenLeft) / 2; int offset = Math.min(spaceAbove, spaceBelow); offset = Math.min(offset, halfVerticalSpace); // We placed oldSel, so offset that item // oldSel.offsetTopAndBottom(-offset); oldSel.offsetLeftAndRight(-offset); // Now offset the selected item to get it into view // sel.offsetTopAndBottom(-offset); sel.offsetLeftAndRight(-offset); } // Fill in views above and below if (!mStackFromBottom) { fillUp(mSelectedPosition - 2, sel.getLeft() - dividerWidth); adjustViewsUpOrDown(); fillDown(mSelectedPosition + 1, sel.getRight() + dividerWidth); } else { fillDown(mSelectedPosition + 1, sel.getRight() + dividerWidth); adjustViewsUpOrDown(); fillUp(mSelectedPosition - 2, sel.getLeft() - dividerWidth); } } 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.getRight(), true, mListPadding.top, 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.getRight(), false, mListPadding.top, 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.getLeft(); // Find space available below the selection into which we can scroll downwards int spaceBelow = bottomSelectionPixel - sel.getRight(); // Don't scroll more than half the height of the list int halfVerticalSpace = (childrenRight - childrenLeft) / 2; int offset = Math.min(spaceAbove, spaceBelow); offset = Math.min(offset, halfVerticalSpace); // Offset the selected item to get it into view // sel.offsetTopAndBottom(offset); sel.offsetLeftAndRight(offset); } // Fill in views above and below fillAboveAndBelow(sel, selectedPosition); } else { int oldLeft = oldSel.getLeft(); /* * Case 3: Staying still */ sel = makeAndAddView(selectedPosition, oldLeft, true, mListPadding.top, true); // We're staying still... if (oldLeft < childrenLeft) { // ... 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.getRight(); if (newBottom < childrenLeft + 20) { // Not enough visible -- bring it onscreen // sel.offsetTopAndBottom(childrenLeft - sel.getTop()); sel.offsetLeftAndRight(childrenLeft - sel.getTop()); } } // Fill in views above and below fillAboveAndBelow(sel, selectedPosition); } return sel; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { // Sets up mListPadding super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (DEBUG_MEASURE) { Log.d(TAG, "onMeasure(). W: " + MeasureSpec.toString(widthMeasureSpec) + " H: " + MeasureSpec.toString(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; mItemCount = mAdapter == null ? 0 : mAdapter.getCount(); if (mItemCount > 0 && (widthMode == MeasureSpec.UNSPECIFIED || heightMode == MeasureSpec.UNSPECIFIED)) { final View child = obtainView(0); measureScrapChild(child, 0, heightMeasureSpec); childWidth = child.getMeasuredWidth(); childHeight = child.getMeasuredHeight(); if (recycleOnMeasure()) { mRecycler.addScrapView(child); } } if (heightMode == MeasureSpec.UNSPECIFIED) { heightSize = mListPadding.top + mListPadding.bottom + childHeight + getHorizontalScrollbarHeight(); } if (widthMode == MeasureSpec.UNSPECIFIED) { widthSize = mListPadding.left + mListPadding.right + childWidth + getHorizontalFadingEdgeLength() * 2; } if (widthMode == MeasureSpec.AT_MOST) { // TODO: after first layout we should maybe start at the first visible position, not 0 widthSize = measureWidthOfChildren(heightMeasureSpec, 0, NO_POSITION, widthSize, -1); } if (DEBUG_MEASURE) { Log.d(TAG, "widthSize: " + widthSize + " heightSize: " + heightSize); } setMeasuredDimension(widthSize, heightSize); mWidthMeasureSpec = widthMeasureSpec; mHeightMeasureSpec = heightMeasureSpec; } private void measureScrapChild(View child, int position, int heightMeasureSpec) { LayoutParams p = (LayoutParams) child.getLayoutParams(); if (p == null) { p = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.FILL_PARENT, 0); child.setLayoutParams(p); } p.viewType = mAdapter.getItemViewType(position); int childheightSpec = ViewGroup.getChildMeasureSpec(heightMeasureSpec, mListPadding.top + mListPadding.bottom, p.height); int lpWidth = p.width; int childWidthSpec; if (lpWidth > 0) { childWidthSpec = MeasureSpec.makeMeasureSpec(lpWidth, MeasureSpec.EXACTLY); } else { childWidthSpec = 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 protected boolean recycleOnMeasure() { return true; } /** * Measures the height of the given range of children (inclusive) and * returns the height with this ListView's padding and divider heights * included. If maxHeight is provided, the measuring will stop when the * current height reaches maxHeight. * * @param heightMeasureSpec The height 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 maxWidth 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 * height 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 measureWidthOfChildren(int heightMeasureSpec, int startPosition, int endPosition, final int maxWidth, int disallowPartialChildPosition) { final ListAdapter adapter = mAdapter; if (adapter == null) { return mListPadding.left + mListPadding.right; } // Include the padding of the list int returnedWidth = mListPadding.left + mListPadding.right; final int dividerWidth = ((mDividerWidth > 0) && mDivider != null) ? mDividerWidth : 0; // The previous height value that was less than maxHeight and contained // no partial children int prevWidthWithoutPartialChild = 0; int i; View child; // mItemCount - 1 since endPosition parameter is inclusive endPosition = (endPosition == NO_POSITION) ? adapter.getCount() - 1 : endPosition; final HAbsListView.RecycleBin recycleBin = mRecycler; final boolean recyle = recycleOnMeasure(); for (i = startPosition; i <= endPosition; ++i) { child = obtainView(i); measureScrapChild(child, i, heightMeasureSpec); if (i > 0) { // Count the divider for all but one child returnedWidth += dividerWidth; } // Recycle the view before we possibly return from the method if (recyle) { recycleBin.addScrapView(child); } returnedWidth += child.getMeasuredWidth(); if (returnedWidth >= maxWidth) { // We went over, figure out which height 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 && (prevWidthWithoutPartialChild > 0) // We have a prev height && (returnedWidth != maxWidth) // i'th child did not fit completely ? prevWidthWithoutPartialChild : maxWidth; } if ((disallowPartialChildPosition >= 0) && (i >= disallowPartialChildPosition)) { prevWidthWithoutPartialChild = returnedWidth; } } // At this point, we went through the range of children, and they each // completely fit, so return the returnedHeight return returnedWidth; } @Override int findMotionRow(int y) { int childCount = getChildCount(); if (childCount > 0) { for (int i = 0; i < childCount; i++) { View v = getChildAt(i); if (y <= v.getRight()) { return mFirstPosition + i; } } return mFirstPosition + childCount - 1; } 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 left 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 left) { boolean tempIsSelected = position == mSelectedPosition; View temp = makeAndAddView(position, left, true, mListPadding.top, tempIsSelected); // Possibly changed again in fillUp if we add rows above this one. mFirstPosition = position; View above; View below; final int dividerWidth = mDividerWidth; if (!mStackFromBottom) { above = fillUp(position - 1, temp.getLeft() - dividerWidth); // This will correct for the top of the first view not touching the top of the list adjustViewsUpOrDown(); below = fillDown(position + 1, temp.getRight() + dividerWidth); int childCount = getChildCount(); if (childCount > 0) { correctTooHigh(childCount); } } else { below = fillDown(position + 1, temp.getRight() + dividerWidth); // This will correct for the bottom of the last view not touching the bottom of the list adjustViewsUpOrDown(); above = fillUp(position - 1, temp.getLeft() - dividerWidth); 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.getRight(); // This is bottom of our drawable area final int end = (getRight() - getLeft()) - mListPadding.right; // 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.getLeft(); // 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 // offsetChildrenTopAndBottom(bottomOffset); ViewCompat.offsetChildrenLeftAndRight(this, bottomOffset); if (mFirstPosition > 0) { // Fill the gap that was opened above mFirstPosition with more rows, if // possible fillUp(mFirstPosition - 1, firstChild.getLeft() - mDividerWidth); // 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.getLeft(); // This is top of our drawable area final int start = mListPadding.left; // This is bottom of our drawable area final int end = (getRight() - getLeft()) - mListPadding.right; // 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.getRight(); 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 && (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 // offsetChildrenTopAndBottom(-topOffset); ViewCompat.offsetChildrenLeftAndRight(this, -topOffset); if (lastPosition < mItemCount - 1) { // Fill the gap that was opened below the last position with more rows, if // possible fillDown(lastPosition + 1, lastChild.getRight() + mDividerWidth); // Close up the remaining gap 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 childrenLeft = mListPadding.left; int childrenRight = getRight() - getLeft() - mListPadding.right; int childCount = getChildCount(); int index; int delta = 0; View sel; View oldSel = null; View oldFirst = null; View newSel = null; View focusLayoutRestoreView = null; // 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."); } 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)); if (ViewDebug.TRACE_RECYCLER) { ViewDebug.trace(getChildAt(i), ViewDebug.RecyclerTraceType.MOVE_TO_SCRAP_HEAP, index, 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 ViewRoot 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(); } // Clear out old views //removeAllViewsInLayout(); detachAllViewsFromParent(); switch (mLayoutMode) { case LAYOUT_SET_SELECTION: if (newSel != null) { sel = fillFromSelection(newSel.getLeft(), childrenLeft, childrenRight); } else { sel = fillFromMiddle(childrenLeft, childrenRight); } break; case LAYOUT_SYNC: sel = fillSpecific(mSyncPosition, mSpecificTop); break; case LAYOUT_FORCE_BOTTOM: sel = fillUp(mItemCount - 1, childrenRight); adjustViewsUpOrDown(); break; case LAYOUT_FORCE_TOP: mFirstPosition = 0; sel = fillFromTop(childrenLeft); adjustViewsUpOrDown(); break; case LAYOUT_SPECIFIC: sel = fillSpecific(reconcileSelectedPosition(), mSpecificLeft); break; case LAYOUT_MOVE_SELECTION: sel = moveSelection(oldSel, newSel, delta, childrenLeft, childrenRight); break; default: if (childCount == 0) { if (!mStackFromBottom) { final int position = lookForSelectablePosition(0, true); setSelectedPositionInt(position); sel = fillFromTop(childrenLeft); } else { final int position = lookForSelectablePosition(mItemCount - 1, false); setSelectedPositionInt(position); sel = fillUp(mItemCount - 1, childrenRight); } } else { if (mSelectedPosition >= 0 && mSelectedPosition < mItemCount) { sel = fillSpecific(mSelectedPosition, oldSel == null ? childrenLeft : oldSel.getLeft()); } else if (mFirstPosition < mItemCount) { sel = fillSpecific(mFirstPosition, oldFirst == null ? childrenLeft : oldFirst.getLeft()); } else { sel = fillSpecific(0, childrenLeft); } } 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.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(sel); } else { sel.setSelected(false); mSelectorRect.setEmpty(); } } else { positionSelector(sel); } mSelectedTop = sel.getTop(); } 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(); } } // 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; mNeedSync = false; setNextSelectedPositionInt(mSelectedPosition); updateScrollIndicators(); if (mItemCount > 0) { checkSelectionChanged(); } invokeOnItemScrollListener(); } finally { if (!blockLayoutRequests) { mBlockLayoutRequests = false; } } } /** * @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 x 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 x, boolean flow, int childrenLeft, boolean selected) { View child; if (!mDataChanged) { // Try to use an exsiting view for this position child = mRecycler.getActiveView(position); if (child != null) { if (ViewDebug.TRACE_RECYCLER) { ViewDebug.trace(child, ViewDebug.RecyclerTraceType.RECYCLE_FROM_ACTIVE_HEAP, position, getChildCount()); } // Found it -- we're using an existing child // This just needs to be positioned setupChild(child, position, x, flow, childrenLeft, selected, true); return child; } } // Make a new view for this position, or convert an unused view if possible child = obtainView(position); // This needs to be positioned and measured setupChild(child, position, x, flow, childrenLeft, selected, false); 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 x 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 x, boolean flowDown, int childrenTop, boolean selected, boolean recycled) { final boolean isSelected = selected && shouldShowSelector(); final boolean updateChildSelected = isSelected != child.isSelected(); final boolean needToMeasure = !recycled || updateChildSelected || child.isLayoutRequested(); // Respect layout params that are already in the view. Otherwise make some up... // noinspection unchecked HAbsListView.LayoutParams p = (HAbsListView.LayoutParams) child.getLayoutParams(); if (p == null) { p = new HAbsListView.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT, 0); } p.viewType = mAdapter.getItemViewType(position); if (recycled || (p.recycledHeaderFooter && p.viewType == AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER)) { attachViewToParent(child, flowDown ? -1 : 0, p); } else { 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 (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { if (child instanceof Checkable) { ((Checkable) child).setChecked(mCheckStates.get(position)); } } if (needToMeasure) { int childHeightSpec = ViewGroup.getChildMeasureSpec(mHeightMeasureSpec, mListPadding.top + mListPadding.bottom, p.height); int lpWidth = p.width; int childWidthSpec = -1; if (lpWidth > 0) { childWidthSpec = MeasureSpec.makeMeasureSpec(lpWidth, MeasureSpec.EXACTLY); } else { childWidthSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); } child.measure(childWidthSpec, childHeightSpec); } else { cleanupLayoutState(child); } final int w = child.getMeasuredWidth(); final int h = child.getMeasuredHeight(); final int childLeft = flowDown ? x : x - w; if (needToMeasure) { final int childRight = childLeft + w; final int childBottom = childrenTop + h; child.layout(childLeft, childrenTop, childRight, childBottom); } else { child.offsetLeftAndRight(childLeft - child.getLeft()); child.offsetTopAndBottom(childrenTop - child.getTop()); } if (mCachingStarted && !child.isDrawingCacheEnabled()) { child.setDrawingCacheEnabled(true); } } @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); } 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); layoutChildren(); } /** * 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; } } @Override public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { boolean populated = super.dispatchPopulateAccessibilityEvent(event); // If the item count is less than 15 then subtract disabled items from the count and // position. Otherwise ignore disabled items. if (!populated) { int itemCount = 0; int currentItemIndex = getSelectedItemPosition(); ListAdapter adapter = getAdapter(); if (adapter != null) { final int count = adapter.getCount(); if (count < 15) { for (int i = 0; i < count; i++) { if (adapter.isEnabled(i)) { itemCount++; } else if (i <= currentItemIndex) { currentItemIndex--; } } } else { itemCount = count; } } event.setItemCount(itemCount); event.setCurrentItemIndex(currentItemIndex); } return populated; } /** * 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) { return false; } if (mDataChanged) { layoutChildren(); } boolean handled = false; int action = event.getAction(); if (action != KeyEvent.ACTION_UP) { if (mSelectedPosition < 0) { switch (keyCode) { case KeyEvent.KEYCODE_DPAD_UP: case KeyEvent.KEYCODE_DPAD_DOWN: case KeyEvent.KEYCODE_DPAD_CENTER: case KeyEvent.KEYCODE_ENTER: case KeyEvent.KEYCODE_SPACE: if (resurrectSelection()) { return true; } } } switch (keyCode) { case KeyEvent.KEYCODE_DPAD_LEFT: if (!event.isAltPressed()) { while (count > 0) { handled = arrowScroll(FOCUS_LEFT); count--; } } else { handled = fullScroll(FOCUS_LEFT); } break; case KeyEvent.KEYCODE_DPAD_RIGHT: if (!event.isAltPressed()) { while (count > 0) { handled = arrowScroll(FOCUS_RIGHT); count--; } } else { handled = fullScroll(FOCUS_RIGHT); } break; case KeyEvent.KEYCODE_DPAD_UP: handled = handleHorizontalFocusWithinListItem(View.FOCUS_UP); break; case KeyEvent.KEYCODE_DPAD_DOWN: handled = handleHorizontalFocusWithinListItem(View.FOCUS_DOWN); break; case KeyEvent.KEYCODE_DPAD_CENTER: case KeyEvent.KEYCODE_ENTER: if (mItemCount > 0 && event.getRepeatCount() == 0) { keyPressed(); } handled = true; break; case KeyEvent.KEYCODE_SPACE: if (mPopup == null || !mPopup.isShowing()) { if (!event.isShiftPressed()) { pageScroll(FOCUS_DOWN); } else { pageScroll(FOCUS_UP); } handled = true; } break; } } if (!handled) { handled = sendToTextFilter(keyCode, count, event); } if (handled) { return true; } else { 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_LEFT) { nextPage = Math.max(0, mSelectedPosition - getChildCount() - 1); } else if (direction == FOCUS_RIGHT) { 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 = getPaddingLeft() + getHorizontalFadingEdgeLength(); if (down && position > mItemCount - getChildCount()) { mLayoutMode = LAYOUT_FORCE_BOTTOM; } if (!down && position < getChildCount()) { mLayoutMode = LAYOUT_FORCE_TOP; } setSelectionInt(position); invokeOnItemScrollListener(); 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) { 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_UP && direction != View.FOCUS_DOWN) { throw new IllegalArgumentException("direction must be one of" + " {View.FOCUS_UP, View.FOCUS_DOWN}"); } 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 nextSelectedPosition = lookForSelectablePositionOnScreen(direction); 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(); 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_LEFT) ? 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 (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(selectedView); mSelectedTop = selectedView.getTop(); } 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_LEFT) { 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 height 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 oldidth = child.getWidth(); measureItem(child); if (child.getMeasuredWidth() != oldidth) { // lay out the view, preserving its top relayoutMeasuredItem(child); // adjust views below appropriately final int widthDelta = child.getMeasuredWidth() - oldidth; for (int i = childIndex + 1; i < numChildren; i++) { // getChildAt(i).offsetTopAndBottom(widthDelta); getChildAt(i).offsetLeftAndRight(widthDelta); } } } /** * 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.WRAP_CONTENT, ViewGroup.LayoutParams.FILL_PARENT); } int childHeightSpec = ViewGroup.getChildMeasureSpec(mHeightMeasureSpec, mListPadding.top + mListPadding.bottom, p.height); int lpWidth = p.width; int childWidthSpec = -1; if (lpWidth > 0) { childWidthSpec = MeasureSpec.makeMeasureSpec(lpWidth, MeasureSpec.EXACTLY); } else { childWidthSpec = 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 = child.getLeft();//mListPadding.left; final int childRight = childLeft + w; final int childTop = mListPadding.top;//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 listRight = getWidth() - mListPadding.right; final int listLeft = mListPadding.left; final int numChildren = getChildCount(); if (direction == View.FOCUS_RIGHT) { int indexToMakeVisible = numChildren - 1; if (nextSelectedPosition != INVALID_POSITION) { indexToMakeVisible = nextSelectedPosition - mFirstPosition; } final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; final View viewToMakeVisible = getChildAt(indexToMakeVisible); int goalRight = listRight; if (positionToMakeVisible < mItemCount - 1) { goalRight -= getArrowScrollPreviewLength(); } if (viewToMakeVisible.getRight() <= goalRight) { // item is fully visible. return 0; } if (nextSelectedPosition != INVALID_POSITION && (goalRight - viewToMakeVisible.getLeft()) >= getMaxScrollAmount()) { // item already has enough of it visible, changing selection is good enough return 0; } int amountToScroll = (viewToMakeVisible.getRight() - goalRight); if ((mFirstPosition + numChildren) == mItemCount) { // last is last in list -> make sure we don't scroll past it final int max = getChildAt(numChildren - 1).getRight() - listRight; amountToScroll = Math.min(amountToScroll, max); } return Math.min(amountToScroll, getMaxScrollAmount()); } else { int indexToMakeVisible = 0; if (nextSelectedPosition != INVALID_POSITION) { indexToMakeVisible = nextSelectedPosition - mFirstPosition; } final int positionToMakeVisible = mFirstPosition + indexToMakeVisible; final View viewToMakeVisible = getChildAt(indexToMakeVisible); int goalLeft = listLeft; if (positionToMakeVisible > 0) { goalLeft += getArrowScrollPreviewLength(); } if (viewToMakeVisible.getLeft() >= goalLeft) { // item is fully visible. return 0; } if (nextSelectedPosition != INVALID_POSITION && (viewToMakeVisible.getRight() - goalLeft) >= getMaxScrollAmount()) { // item already has enough of it visible, changing selection is good enough return 0; } int amountToScroll = (goalLeft - viewToMakeVisible.getLeft()); if (mFirstPosition == 0) { // first is first in list -> make sure we don't scroll past it final int max = listLeft - getChildAt(0).getLeft(); 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 android.widget.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_RIGHT) { 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) { 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_LEFT) { final boolean topFadingEdgeShowing = (mFirstPosition > 0); final int listLeft = mListPadding.top + (topFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); final int ySearchPoint = (selectedView != null && selectedView.getLeft() > listLeft) ? selectedView.getLeft() : listLeft; mTempRect.set(0, ySearchPoint, 0, ySearchPoint); } else { final boolean bottomFadingEdgeShowing = (mFirstPosition + getChildCount() - 1) < mItemCount; final int listRight = getWidth() - mListPadding.right - (bottomFadingEdgeShowing ? getArrowScrollPreviewLength() : 0); final int ySearchPoint = (selectedView != null && selectedView.getRight() < listRight) ? selectedView.getRight() : listRight; 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 * direciton. * @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 listRight = getRight() - getLeft() - mListPadding.right; if (mTempRect.right < mListPadding.left) { distance = mListPadding.left - mTempRect.right; } else if (mTempRect.left > listRight) { distance = mTempRect.left - listRight; } 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) { // offsetChildrenTopAndBottom(amount); ViewCompat.offsetChildrenLeftAndRight(this, amount); final int listRight = getWidth() - mListPadding.right; final int listLeft = mListPadding.left; final HAbsListView.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.getRight() < listRight) { 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.getRight() < listRight) { // offsetChildrenTopAndBottom(listBottom - last.getBottom()); ViewCompat.offsetChildrenLeftAndRight(this, listRight - last.getBottom()); } // top views may be panned off screen View first = getChildAt(0); while (first.getRight() < listLeft) { HAbsListView.LayoutParams layoutParams = (LayoutParams) first.getLayoutParams(); if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { removeViewInLayout(first); recycleBin.addScrapView(first); } else { detachViewFromParent(first); } first = getChildAt(0); mFirstPosition++; } } else { // shifted items down View first = getChildAt(0); // may need to pan views into top while ((first.getLeft() > listLeft) && (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.getLeft() > listLeft) { // offsetChildrenTopAndBottom(listTop - first.getTop()); ViewCompat.offsetChildrenLeftAndRight(this, listLeft - first.getTop()); } int lastIndex = getChildCount() - 1; View last = getChildAt(lastIndex); // bottom view may be panned off screen while (last.getLeft() > listRight) { HAbsListView.LayoutParams layoutParams = (LayoutParams) last.getLayoutParams(); if (recycleBin.shouldRecycleViewType(layoutParams.viewType)) { removeViewInLayout(last); recycleBin.addScrapView(last); } else { detachViewFromParent(last); } last = getChildAt(--lastIndex); } } } private View addViewAbove(View theView, int position) { int abovePosition = position - 1; View view = obtainView(abovePosition); int edgeOfNewChild = theView.getLeft() - mDividerWidth; setupChild(view, abovePosition, edgeOfNewChild, false, mListPadding.top, false, false); return view; } private View addViewBelow(View theView, int position) { int belowPosition = position + 1; View view = obtainView(belowPosition); int edgeOfNewChild = theView.getRight() + mDividerWidth; setupChild(view, belowPosition, edgeOfNewChild, true, mListPadding.top, false, false); 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; } /** * @hide Pending API council approval. */ @Override public boolean isOpaque() { return (mCachingStarted && mIsCacheColorOpaque && mDividerIsOpaque && // bysong true) //hasOpaqueScrollbars()) || super.isOpaque(); } @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); } @Override protected void dispatchDraw(Canvas canvas) { // Draw the dividers final int dividerHeight = mDividerWidth; if (dividerHeight > 0 && mDivider != null) { // 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 footerLimit = mItemCount - 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 = ReflectUtil.view_isOpaque(this)//isOpaque() && !super.isOpaque(); if (fillForMissingDividers && mDividerPaint == null && mIsCacheColorOpaque) { mDividerPaint = new Paint(); mDividerPaint.setColor(getCacheColorHint()); } final Paint paint = mDividerPaint; if (!mStackFromBottom) { int bottom; int listBottom = getBottom() - getTop() - mListPadding.bottom; 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 (bottom < listBottom) { 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); } } } } } else { int top; int listTop = mListPadding.top; for (int i = 0; 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 > listTop) { 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); } } } } } } // Draw the indicators (these should be drawn above the dividers) and children super.dispatchDraw(canvas); } /** * 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; final boolean clipDivider = mClipDivider; if (!clipDivider) { divider.setBounds(bounds); } else { canvas.save(); canvas.clipRect(bounds); } divider.draw(canvas); if (clipDivider) { canvas.restore(); } } /** * 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 height, you should also call {@link #setDividerHeight(int)} * * @param divider The drawable to use. */ public void setDivider(Drawable divider) { if (divider != null) { mDividerWidth = divider.getIntrinsicHeight(); mClipDivider = divider instanceof ColorDrawable; } else { mDividerWidth = 0; mClipDivider = false; } mDivider = divider; mDividerIsOpaque = divider == null || divider.getOpacity() == PixelFormat.OPAQUE; requestLayoutIfNecessary(); } /** * @return Returns the height of the divider that will be drawn between each item in the list. */ public int getDividerHeight() { return mDividerWidth; } /** * Sets the height of the divider that will be drawn between each item in the list. Calling * this will override the intrinsic height as set by {@link #setDivider(Drawable)} * * @param height The new height of the divider in pixels. */ public void setDividerHeight(int height) { mDividerWidth = height; requestLayoutIfNecessary(); } /** * 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(); } @Override protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) { super.onFocusChanged(gainFocus, direction, previouslyFocusedRect); int closetChildIndex = -1; if (gainFocus && previouslyFocusedRect != null) { previouslyFocusedRect.offset(getScrollX(), getScrollY()); // 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; final ListAdapter adapter = mAdapter; 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; } } } if (closetChildIndex >= 0) { setSelection(closetChildIndex + mFirstPosition); } 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(); } } /* (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 findViewTraversalX(int id) { View v = null; //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; // bysong // if (!v.isRootNamespace()) { if (!ReflectUtil.view_isRootNamespace(v)) { v = v.findViewById(id); if (v != null) { return v; } } } } return null; } /* (non-Javadoc) * @see android.view.View#findViewWithTag(String) * First look in our children, then in any header and footer views that may be scrolled off. */ //@Override protected View findViewWithTagTraversalX(Object tag) { View v = null; // v = super.findViewWithTagTraversal(tag); if (v == null) { v = findViewTagInHeadersOrFooters(mHeaderViewInfos, tag); if (v != null) { return v; } v = findViewTagInHeadersOrFooters(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 findViewTagInHeadersOrFooters(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; // bysong // if (!v.isRootNamespace()) { if (!ReflectUtil.view_isRootNamespace(v)) { v = v.findViewWithTag(tag); if (v != null) { return v; } } } } return null; } @Override public boolean onTouchEvent(MotionEvent ev) { if (mItemsCanFocus && ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() != 0) { // Don't handle edge touches immediately -- they may actually belong to one of our // descendants. return false; } return super.onTouchEvent(ev); } /** * @see #setChoiceMode(int) * * @return The current choice mode */ public int getChoiceMode() { return mChoiceMode; } /** * Defines the choice behavior for the List. By default, Lists do not have any choice behavior * ({@link #CHOICE_MODE_NONE}). By setting the choiceMode to {@link #CHOICE_MODE_SINGLE}, the * List allows up to one item to be in a chosen state. By setting the choiceMode to * {@link #CHOICE_MODE_MULTIPLE}, the list allows any number of items to be chosen. * * @param choiceMode One of {@link #CHOICE_MODE_NONE}, {@link #CHOICE_MODE_SINGLE}, or * {@link #CHOICE_MODE_MULTIPLE} */ public void setChoiceMode(int choiceMode) { mChoiceMode = choiceMode; if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates == null) { mCheckStates = new SparseBooleanArray(); } } @Override public boolean performItemClick(View view, int position, long id) { boolean handled = false; if (mChoiceMode != CHOICE_MODE_NONE) { handled = true; if (mChoiceMode == CHOICE_MODE_MULTIPLE) { boolean oldValue = mCheckStates.get(position, false); mCheckStates.put(position, !oldValue); } else { boolean oldValue = mCheckStates.get(position, false); if (!oldValue) { mCheckStates.clear(); mCheckStates.put(position, true); } } mDataChanged = true; rememberSyncState(); requestLayout(); } handled |= super.performItemClick(view, position, id); return handled; } /** * Sets the checked state of the specified position. The is only valid if * the choice mode has been set to {@link #CHOICE_MODE_SINGLE} or * {@link #CHOICE_MODE_MULTIPLE}. * * @param position The item whose checked state is to be checked * @param value The new checked sate for the item */ public void setItemChecked(int position, boolean value) { if (mChoiceMode == CHOICE_MODE_NONE) { return; } if (mChoiceMode == CHOICE_MODE_MULTIPLE) { mCheckStates.put(position, value); } else { // Clear the old value: if something was selected and value == false // then it is unselected mCheckStates.clear(); // If value == true, select the appropriate position // this may end up selecting the value we just cleared but this way // we don't have to first to a get(position) if (value) { mCheckStates.put(position, true); } } // Do not generate a data change while we are in the layout phase if (!mInLayout && !mBlockLayoutRequests) { mDataChanged = true; rememberSyncState(); requestLayout(); } } /** * Returns the checked state of the specified position. The result is only * valid if the choice mode has not been set to {@link #CHOICE_MODE_SINGLE} * or {@link #CHOICE_MODE_MULTIPLE}. * * @param position The item whose checked state to return * @return The item's checked state * * @see #setChoiceMode(int) */ public boolean isItemChecked(int position) { if (mChoiceMode != CHOICE_MODE_NONE && mCheckStates != null) { return mCheckStates.get(position); } return false; } /** * Returns the currently checked item. The result is only valid if the choice * mode has not been set to {@link #CHOICE_MODE_SINGLE}. * * @return The position of the currently checked item or * {@link #INVALID_POSITION} if nothing is selected * * @see #setChoiceMode(int) */ public int getCheckedItemPosition() { if (mChoiceMode == CHOICE_MODE_SINGLE && mCheckStates != null && mCheckStates.size() == 1) { return mCheckStates.keyAt(0); } return INVALID_POSITION; } /** * Returns the set of checked items in the list. The result is only valid if * the choice mode has not been set to {@link #CHOICE_MODE_SINGLE}. * * @return A SparseBooleanArray which will return true for each call to * get(int position) where position is a position in the list. */ public SparseBooleanArray getCheckedItemPositions() { if (mChoiceMode != CHOICE_MODE_NONE) { return mCheckStates; } 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_SINGLE}. * * @return A new array which contains the id of each checked item in the list. */ public long[] getCheckItemIds() { 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; for (int i = 0; i < count; i++) { ids[i] = adapter.getItemId(states.keyAt(i)); } return ids; } return new long[0]; } /** * Clear any choices previously set */ public void clearChoices() { if (mCheckStates != null) { mCheckStates.clear(); } } static class SavedState extends BaseSavedState { SparseBooleanArray checkState; /** * Constructor called from {@link HListView#onSaveInstanceState()} */ SavedState(Parcelable superState, SparseBooleanArray checkState) { super(superState); this.checkState = checkState; } /** * Constructor called from {@link #CREATOR} */ private SavedState(Parcel in) { super(in); checkState = in.readSparseBooleanArray(); } @Override public void writeToParcel(Parcel out, int flags) { super.writeToParcel(out, flags); out.writeSparseBooleanArray(checkState); } @Override public String toString() { return "ListView.SavedState{" + Integer.toHexString(System.identityHashCode(this)) + " checkState=" + checkState + "}"; } public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { public SavedState createFromParcel(Parcel in) { return new SavedState(in); } public SavedState[] newArray(int size) { return new SavedState[size]; } }; } @Override public Parcelable onSaveInstanceState() { Parcelable superState = super.onSaveInstanceState(); return new SavedState(superState, mCheckStates); } @Override public void onRestoreInstanceState(Parcelable state) { SavedState ss = (SavedState) state; super.onRestoreInstanceState(ss.getSuperState()); if (ss.checkState != null) { mCheckStates = ss.checkState; } } }