Java tutorial
/* * Copyright (C) 2009 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 android.widget; import android.annotation.NonNull; import android.annotation.UnsupportedAppUsage; import android.content.Context; import android.content.res.Configuration; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Rect; import android.os.Build; import android.os.Bundle; import android.os.Parcel; import android.os.Parcelable; import android.util.AttributeSet; import android.util.Log; import android.view.FocusFinder; import android.view.InputDevice; import android.view.KeyEvent; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewDebug; import android.view.ViewGroup; import android.view.ViewHierarchyEncoder; import android.view.ViewParent; import android.view.accessibility.AccessibilityEvent; import android.view.accessibility.AccessibilityNodeInfo; import android.view.animation.AnimationUtils; import com.android.internal.R; import java.util.List; /** * Layout container for a view hierarchy that can be scrolled by the user, * allowing it to be larger than the physical display. A HorizontalScrollView * is a {@link FrameLayout}, meaning you should place one child in it * containing the entire contents to scroll; this child may itself be a layout * manager with a complex hierarchy of objects. A child that is often used * is a {@link LinearLayout} in a horizontal orientation, presenting a horizontal * array of top-level items that the user can scroll through. * * <p>The {@link TextView} class also * takes care of its own scrolling, so does not require a HorizontalScrollView, but * using the two together is possible to achieve the effect of a text view * within a larger container. * * <p>HorizontalScrollView only supports horizontal scrolling. For vertical scrolling, * use either {@link ScrollView} or {@link ListView}. * * @attr ref android.R.styleable#HorizontalScrollView_fillViewport */ public class HorizontalScrollView extends FrameLayout { private static final int ANIMATED_SCROLL_GAP = ScrollView.ANIMATED_SCROLL_GAP; private static final float MAX_SCROLL_FACTOR = ScrollView.MAX_SCROLL_FACTOR; private static final String TAG = "HorizontalScrollView"; private long mLastScroll; private final Rect mTempRect = new Rect(); @UnsupportedAppUsage private OverScroller mScroller; @UnsupportedAppUsage private EdgeEffect mEdgeGlowLeft; @UnsupportedAppUsage private EdgeEffect mEdgeGlowRight; /** * Position of the last motion event. */ @UnsupportedAppUsage private int mLastMotionX; /** * True when the layout has changed but the traversal has not come through yet. * Ideally the view hierarchy would keep track of this for us. */ private boolean mIsLayoutDirty = true; /** * The child to give focus to in the event that a child has requested focus while the * layout is dirty. This prevents the scroll from being wrong if the child has not been * laid out before requesting focus. */ @UnsupportedAppUsage private View mChildToScrollTo = null; /** * True if the user is currently dragging this ScrollView around. This is * not the same as 'is being flinged', which can be checked by * mScroller.isFinished() (flinging begins when the user lifts his finger). */ @UnsupportedAppUsage private boolean mIsBeingDragged = false; /** * Determines speed during touch scrolling */ @UnsupportedAppUsage private VelocityTracker mVelocityTracker; /** * When set to true, the scroll view measure its child to make it fill the currently * visible area. */ @ViewDebug.ExportedProperty(category = "layout") private boolean mFillViewport; /** * Whether arrow scrolling is animated. */ private boolean mSmoothScrollingEnabled = true; private int mTouchSlop; private int mMinimumVelocity; private int mMaximumVelocity; @UnsupportedAppUsage private int mOverscrollDistance; @UnsupportedAppUsage private int mOverflingDistance; private float mHorizontalScrollFactor; /** * ID of the active pointer. This is used to retain consistency during * drags/flings if multiple pointers are used. */ private int mActivePointerId = INVALID_POINTER; /** * Sentinel value for no current active pointer. * Used by {@link #mActivePointerId}. */ private static final int INVALID_POINTER = -1; private SavedState mSavedState; public HorizontalScrollView(Context context) { this(context, null); } public HorizontalScrollView(Context context, AttributeSet attrs) { this(context, attrs, com.android.internal.R.attr.horizontalScrollViewStyle); } public HorizontalScrollView(Context context, AttributeSet attrs, int defStyleAttr) { this(context, attrs, defStyleAttr, 0); } public HorizontalScrollView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); initScrollView(); final TypedArray a = context.obtainStyledAttributes(attrs, android.R.styleable.HorizontalScrollView, defStyleAttr, defStyleRes); setFillViewport(a.getBoolean(android.R.styleable.HorizontalScrollView_fillViewport, false)); a.recycle(); if (context.getResources().getConfiguration().uiMode == Configuration.UI_MODE_TYPE_WATCH) { setRevealOnFocusHint(false); } } @Override protected float getLeftFadingEdgeStrength() { if (getChildCount() == 0) { return 0.0f; } final int length = getHorizontalFadingEdgeLength(); if (mScrollX < length) { return mScrollX / (float) length; } return 1.0f; } @Override protected float getRightFadingEdgeStrength() { if (getChildCount() == 0) { return 0.0f; } final int length = getHorizontalFadingEdgeLength(); final int rightEdge = getWidth() - mPaddingRight; final int span = getChildAt(0).getRight() - mScrollX - rightEdge; if (span < length) { return span / (float) length; } return 1.0f; } /** * @return The maximum amount this scroll view will scroll in response to * an arrow event. */ public int getMaxScrollAmount() { return (int) (MAX_SCROLL_FACTOR * (mRight - mLeft)); } private void initScrollView() { mScroller = new OverScroller(getContext()); setFocusable(true); setDescendantFocusability(FOCUS_AFTER_DESCENDANTS); setWillNotDraw(false); final ViewConfiguration configuration = ViewConfiguration.get(mContext); mTouchSlop = configuration.getScaledTouchSlop(); mMinimumVelocity = configuration.getScaledMinimumFlingVelocity(); mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); mOverscrollDistance = configuration.getScaledOverscrollDistance(); mOverflingDistance = configuration.getScaledOverflingDistance(); mHorizontalScrollFactor = configuration.getScaledHorizontalScrollFactor(); } @Override public void addView(View child) { if (getChildCount() > 0) { throw new IllegalStateException("HorizontalScrollView can host only one direct child"); } super.addView(child); } @Override public void addView(View child, int index) { if (getChildCount() > 0) { throw new IllegalStateException("HorizontalScrollView can host only one direct child"); } super.addView(child, index); } @Override public void addView(View child, ViewGroup.LayoutParams params) { if (getChildCount() > 0) { throw new IllegalStateException("HorizontalScrollView can host only one direct child"); } super.addView(child, params); } @Override public void addView(View child, int index, ViewGroup.LayoutParams params) { if (getChildCount() > 0) { throw new IllegalStateException("HorizontalScrollView can host only one direct child"); } super.addView(child, index, params); } /** * @return Returns true this HorizontalScrollView can be scrolled */ private boolean canScroll() { View child = getChildAt(0); if (child != null) { int childWidth = child.getWidth(); return getWidth() < childWidth + mPaddingLeft + mPaddingRight; } return false; } /** * Indicates whether this HorizontalScrollView's content is stretched to * fill the viewport. * * @return True if the content fills the viewport, false otherwise. * * @attr ref android.R.styleable#HorizontalScrollView_fillViewport */ public boolean isFillViewport() { return mFillViewport; } /** * Indicates this HorizontalScrollView whether it should stretch its content width * to fill the viewport or not. * * @param fillViewport True to stretch the content's width to the viewport's * boundaries, false otherwise. * * @attr ref android.R.styleable#HorizontalScrollView_fillViewport */ public void setFillViewport(boolean fillViewport) { if (fillViewport != mFillViewport) { mFillViewport = fillViewport; requestLayout(); } } /** * @return Whether arrow scrolling will animate its transition. */ public boolean isSmoothScrollingEnabled() { return mSmoothScrollingEnabled; } /** * Set whether arrow scrolling will animate its transition. * @param smoothScrollingEnabled whether arrow scrolling will animate its transition */ public void setSmoothScrollingEnabled(boolean smoothScrollingEnabled) { mSmoothScrollingEnabled = smoothScrollingEnabled; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (!mFillViewport) { return; } final int widthMode = MeasureSpec.getMode(widthMeasureSpec); if (widthMode == MeasureSpec.UNSPECIFIED) { return; } if (getChildCount() > 0) { final View child = getChildAt(0); final int widthPadding; final int heightPadding; final FrameLayout.LayoutParams lp = (LayoutParams) child.getLayoutParams(); final int targetSdkVersion = getContext().getApplicationInfo().targetSdkVersion; if (targetSdkVersion >= Build.VERSION_CODES.M) { widthPadding = mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin; heightPadding = mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin; } else { widthPadding = mPaddingLeft + mPaddingRight; heightPadding = mPaddingTop + mPaddingBottom; } int desiredWidth = getMeasuredWidth() - widthPadding; if (child.getMeasuredWidth() < desiredWidth) { final int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(desiredWidth, MeasureSpec.EXACTLY); final int childHeightMeasureSpec = getChildMeasureSpec(heightMeasureSpec, heightPadding, lp.height); child.measure(childWidthMeasureSpec, childHeightMeasureSpec); } } } @Override public boolean dispatchKeyEvent(KeyEvent event) { // Let the focused view and/or our descendants get the key first return super.dispatchKeyEvent(event) || executeKeyEvent(event); } /** * You can call this function yourself to have the scroll view perform * scrolling from a key event, just as if the event had been dispatched to * it by the view hierarchy. * * @param event The key event to execute. * @return Return true if the event was handled, else false. */ public boolean executeKeyEvent(KeyEvent event) { mTempRect.setEmpty(); if (!canScroll()) { if (isFocused()) { View currentFocused = findFocus(); if (currentFocused == this) currentFocused = null; View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, View.FOCUS_RIGHT); return nextFocused != null && nextFocused != this && nextFocused.requestFocus(View.FOCUS_RIGHT); } return false; } boolean handled = false; if (event.getAction() == KeyEvent.ACTION_DOWN) { switch (event.getKeyCode()) { case KeyEvent.KEYCODE_DPAD_LEFT: if (!event.isAltPressed()) { handled = arrowScroll(View.FOCUS_LEFT); } else { handled = fullScroll(View.FOCUS_LEFT); } break; case KeyEvent.KEYCODE_DPAD_RIGHT: if (!event.isAltPressed()) { handled = arrowScroll(View.FOCUS_RIGHT); } else { handled = fullScroll(View.FOCUS_RIGHT); } break; case KeyEvent.KEYCODE_SPACE: pageScroll(event.isShiftPressed() ? View.FOCUS_LEFT : View.FOCUS_RIGHT); break; } } return handled; } private boolean inChild(int x, int y) { if (getChildCount() > 0) { final int scrollX = mScrollX; final View child = getChildAt(0); return !(y < child.getTop() || y >= child.getBottom() || x < child.getLeft() - scrollX || x >= child.getRight() - scrollX); } return false; } private void initOrResetVelocityTracker() { if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } else { mVelocityTracker.clear(); } } private void initVelocityTrackerIfNotExists() { if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } } @UnsupportedAppUsage private void recycleVelocityTracker() { if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } @Override public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) { if (disallowIntercept) { recycleVelocityTracker(); } super.requestDisallowInterceptTouchEvent(disallowIntercept); } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { /* * This method JUST determines whether we want to intercept the motion. * If we return true, onMotionEvent will be called and we do the actual * scrolling there. */ /* * Shortcut the most recurring case: the user is in the dragging * state and he is moving his finger. We want to intercept this * motion. */ final int action = ev.getAction(); if ((action == MotionEvent.ACTION_MOVE) && (mIsBeingDragged)) { return true; } if (super.onInterceptTouchEvent(ev)) { return true; } switch (action & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_MOVE: { /* * mIsBeingDragged == false, otherwise the shortcut would have caught it. Check * whether the user has moved far enough from his original down touch. */ /* * Locally do absolute value. mLastMotionX is set to the x value * of the down event. */ final int activePointerId = mActivePointerId; if (activePointerId == INVALID_POINTER) { // If we don't have a valid id, the touch down wasn't on content. break; } final int pointerIndex = ev.findPointerIndex(activePointerId); if (pointerIndex == -1) { Log.e(TAG, "Invalid pointerId=" + activePointerId + " in onInterceptTouchEvent"); break; } final int x = (int) ev.getX(pointerIndex); final int xDiff = (int) Math.abs(x - mLastMotionX); if (xDiff > mTouchSlop) { mIsBeingDragged = true; mLastMotionX = x; initVelocityTrackerIfNotExists(); mVelocityTracker.addMovement(ev); if (mParent != null) mParent.requestDisallowInterceptTouchEvent(true); } break; } case MotionEvent.ACTION_DOWN: { final int x = (int) ev.getX(); if (!inChild((int) x, (int) ev.getY())) { mIsBeingDragged = false; recycleVelocityTracker(); break; } /* * Remember location of down touch. * ACTION_DOWN always refers to pointer index 0. */ mLastMotionX = x; mActivePointerId = ev.getPointerId(0); initOrResetVelocityTracker(); mVelocityTracker.addMovement(ev); /* * If being flinged and user touches the screen, initiate drag; * otherwise don't. mScroller.isFinished should be false when * being flinged. */ mIsBeingDragged = !mScroller.isFinished(); break; } case MotionEvent.ACTION_CANCEL: case MotionEvent.ACTION_UP: /* Release the drag */ mIsBeingDragged = false; mActivePointerId = INVALID_POINTER; if (mScroller.springBack(mScrollX, mScrollY, 0, getScrollRange(), 0, 0)) { postInvalidateOnAnimation(); } break; case MotionEvent.ACTION_POINTER_DOWN: { final int index = ev.getActionIndex(); mLastMotionX = (int) ev.getX(index); mActivePointerId = ev.getPointerId(index); break; } case MotionEvent.ACTION_POINTER_UP: onSecondaryPointerUp(ev); mLastMotionX = (int) ev.getX(ev.findPointerIndex(mActivePointerId)); break; } /* * The only time we want to intercept motion events is if we are in the * drag mode. */ return mIsBeingDragged; } @Override public boolean onTouchEvent(MotionEvent ev) { initVelocityTrackerIfNotExists(); mVelocityTracker.addMovement(ev); final int action = ev.getAction(); switch (action & MotionEvent.ACTION_MASK) { case MotionEvent.ACTION_DOWN: { if (getChildCount() == 0) { return false; } if ((mIsBeingDragged = !mScroller.isFinished())) { final ViewParent parent = getParent(); if (parent != null) { parent.requestDisallowInterceptTouchEvent(true); } } /* * If being flinged and user touches, stop the fling. isFinished * will be false if being flinged. */ if (!mScroller.isFinished()) { mScroller.abortAnimation(); } // Remember where the motion event started mLastMotionX = (int) ev.getX(); mActivePointerId = ev.getPointerId(0); break; } case MotionEvent.ACTION_MOVE: final int activePointerIndex = ev.findPointerIndex(mActivePointerId); if (activePointerIndex == -1) { Log.e(TAG, "Invalid pointerId=" + mActivePointerId + " in onTouchEvent"); break; } final int x = (int) ev.getX(activePointerIndex); int deltaX = mLastMotionX - x; if (!mIsBeingDragged && Math.abs(deltaX) > mTouchSlop) { final ViewParent parent = getParent(); if (parent != null) { parent.requestDisallowInterceptTouchEvent(true); } mIsBeingDragged = true; if (deltaX > 0) { deltaX -= mTouchSlop; } else { deltaX += mTouchSlop; } } if (mIsBeingDragged) { // Scroll to follow the motion event mLastMotionX = x; final int oldX = mScrollX; final int oldY = mScrollY; final int range = getScrollRange(); final int overscrollMode = getOverScrollMode(); final boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS || (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0); // Calling overScrollBy will call onOverScrolled, which // calls onScrollChanged if applicable. if (overScrollBy(deltaX, 0, mScrollX, 0, range, 0, mOverscrollDistance, 0, true)) { // Break our velocity if we hit a scroll barrier. mVelocityTracker.clear(); } if (canOverscroll) { final int pulledToX = oldX + deltaX; if (pulledToX < 0) { mEdgeGlowLeft.onPull((float) deltaX / getWidth(), 1.f - ev.getY(activePointerIndex) / getHeight()); if (!mEdgeGlowRight.isFinished()) { mEdgeGlowRight.onRelease(); } } else if (pulledToX > range) { mEdgeGlowRight.onPull((float) deltaX / getWidth(), ev.getY(activePointerIndex) / getHeight()); if (!mEdgeGlowLeft.isFinished()) { mEdgeGlowLeft.onRelease(); } } if (mEdgeGlowLeft != null && (!mEdgeGlowLeft.isFinished() || !mEdgeGlowRight.isFinished())) { postInvalidateOnAnimation(); } } } break; case MotionEvent.ACTION_UP: if (mIsBeingDragged) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); int initialVelocity = (int) velocityTracker.getXVelocity(mActivePointerId); if (getChildCount() > 0) { if ((Math.abs(initialVelocity) > mMinimumVelocity)) { fling(-initialVelocity); } else { if (mScroller.springBack(mScrollX, mScrollY, 0, getScrollRange(), 0, 0)) { postInvalidateOnAnimation(); } } } mActivePointerId = INVALID_POINTER; mIsBeingDragged = false; recycleVelocityTracker(); if (mEdgeGlowLeft != null) { mEdgeGlowLeft.onRelease(); mEdgeGlowRight.onRelease(); } } break; case MotionEvent.ACTION_CANCEL: if (mIsBeingDragged && getChildCount() > 0) { if (mScroller.springBack(mScrollX, mScrollY, 0, getScrollRange(), 0, 0)) { postInvalidateOnAnimation(); } mActivePointerId = INVALID_POINTER; mIsBeingDragged = false; recycleVelocityTracker(); if (mEdgeGlowLeft != null) { mEdgeGlowLeft.onRelease(); mEdgeGlowRight.onRelease(); } } break; case MotionEvent.ACTION_POINTER_UP: onSecondaryPointerUp(ev); break; } return true; } private void onSecondaryPointerUp(MotionEvent ev) { final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT; final int pointerId = ev.getPointerId(pointerIndex); if (pointerId == mActivePointerId) { // This was our active pointer going up. Choose a new // active pointer and adjust accordingly. // TODO: Make this decision more intelligent. final int newPointerIndex = pointerIndex == 0 ? 1 : 0; mLastMotionX = (int) ev.getX(newPointerIndex); mActivePointerId = ev.getPointerId(newPointerIndex); if (mVelocityTracker != null) { mVelocityTracker.clear(); } } } @Override public boolean onGenericMotionEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_SCROLL: { if (!mIsBeingDragged) { final float axisValue; if (event.isFromSource(InputDevice.SOURCE_CLASS_POINTER)) { if ((event.getMetaState() & KeyEvent.META_SHIFT_ON) != 0) { axisValue = -event.getAxisValue(MotionEvent.AXIS_VSCROLL); } else { axisValue = event.getAxisValue(MotionEvent.AXIS_HSCROLL); } } else if (event.isFromSource(InputDevice.SOURCE_ROTARY_ENCODER)) { axisValue = event.getAxisValue(MotionEvent.AXIS_SCROLL); } else { axisValue = 0; } final int delta = Math.round(axisValue * mHorizontalScrollFactor); if (delta != 0) { final int range = getScrollRange(); int oldScrollX = mScrollX; int newScrollX = oldScrollX + delta; if (newScrollX < 0) { newScrollX = 0; } else if (newScrollX > range) { newScrollX = range; } if (newScrollX != oldScrollX) { super.scrollTo(newScrollX, mScrollY); return true; } } } } } return super.onGenericMotionEvent(event); } @Override public boolean shouldDelayChildPressedState() { return true; } @Override protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX, boolean clampedY) { // Treat animating scrolls differently; see #computeScroll() for why. if (!mScroller.isFinished()) { final int oldX = mScrollX; final int oldY = mScrollY; mScrollX = scrollX; mScrollY = scrollY; invalidateParentIfNeeded(); onScrollChanged(mScrollX, mScrollY, oldX, oldY); if (clampedX) { mScroller.springBack(mScrollX, mScrollY, 0, getScrollRange(), 0, 0); } } else { super.scrollTo(scrollX, scrollY); } awakenScrollBars(); } /** @hide */ @Override public boolean performAccessibilityActionInternal(int action, Bundle arguments) { if (super.performAccessibilityActionInternal(action, arguments)) { return true; } switch (action) { case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD: case R.id.accessibilityActionScrollRight: { if (!isEnabled()) { return false; } final int viewportWidth = getWidth() - mPaddingLeft - mPaddingRight; final int targetScrollX = Math.min(mScrollX + viewportWidth, getScrollRange()); if (targetScrollX != mScrollX) { smoothScrollTo(targetScrollX, 0); return true; } } return false; case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD: case R.id.accessibilityActionScrollLeft: { if (!isEnabled()) { return false; } final int viewportWidth = getWidth() - mPaddingLeft - mPaddingRight; final int targetScrollX = Math.max(0, mScrollX - viewportWidth); if (targetScrollX != mScrollX) { smoothScrollTo(targetScrollX, 0); return true; } } return false; } return false; } @Override public CharSequence getAccessibilityClassName() { return HorizontalScrollView.class.getName(); } /** @hide */ @Override public void onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info) { super.onInitializeAccessibilityNodeInfoInternal(info); final int scrollRange = getScrollRange(); if (scrollRange > 0) { info.setScrollable(true); if (isEnabled() && mScrollX > 0) { info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_BACKWARD); info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_LEFT); } if (isEnabled() && mScrollX < scrollRange) { info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_FORWARD); info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_RIGHT); } } } /** @hide */ @Override public void onInitializeAccessibilityEventInternal(AccessibilityEvent event) { super.onInitializeAccessibilityEventInternal(event); event.setScrollable(getScrollRange() > 0); event.setScrollX(mScrollX); event.setScrollY(mScrollY); event.setMaxScrollX(getScrollRange()); event.setMaxScrollY(mScrollY); } private int getScrollRange() { int scrollRange = 0; if (getChildCount() > 0) { View child = getChildAt(0); scrollRange = Math.max(0, child.getWidth() - (getWidth() - mPaddingLeft - mPaddingRight)); } return scrollRange; } /** * <p> * Finds the next focusable component that fits in this View's bounds * (excluding fading edges) pretending that this View's left is located at * the parameter left. * </p> * * @param leftFocus look for a candidate is the one at the left of the bounds * if leftFocus is true, or at the right of the bounds if leftFocus * is false * @param left the left offset of the bounds in which a focusable must be * found (the fading edge is assumed to start at this position) * @param preferredFocusable the View that has highest priority and will be * returned if it is within my bounds (null is valid) * @return the next focusable component in the bounds or null if none can be found */ private View findFocusableViewInMyBounds(final boolean leftFocus, final int left, View preferredFocusable) { /* * The fading edge's transparent side should be considered for focus * since it's mostly visible, so we divide the actual fading edge length * by 2. */ final int fadingEdgeLength = getHorizontalFadingEdgeLength() / 2; final int leftWithoutFadingEdge = left + fadingEdgeLength; final int rightWithoutFadingEdge = left + getWidth() - fadingEdgeLength; if ((preferredFocusable != null) && (preferredFocusable.getLeft() < rightWithoutFadingEdge) && (preferredFocusable.getRight() > leftWithoutFadingEdge)) { return preferredFocusable; } return findFocusableViewInBounds(leftFocus, leftWithoutFadingEdge, rightWithoutFadingEdge); } /** * <p> * Finds the next focusable component that fits in the specified bounds. * </p> * * @param leftFocus look for a candidate is the one at the left of the bounds * if leftFocus is true, or at the right of the bounds if * leftFocus is false * @param left the left offset of the bounds in which a focusable must be * found * @param right the right offset of the bounds in which a focusable must * be found * @return the next focusable component in the bounds or null if none can * be found */ private View findFocusableViewInBounds(boolean leftFocus, int left, int right) { List<View> focusables = getFocusables(View.FOCUS_FORWARD); View focusCandidate = null; /* * A fully contained focusable is one where its left is below the bound's * left, and its right is above the bound's right. A partially * contained focusable is one where some part of it is within the * bounds, but it also has some part that is not within bounds. A fully contained * focusable is preferred to a partially contained focusable. */ boolean foundFullyContainedFocusable = false; int count = focusables.size(); for (int i = 0; i < count; i++) { View view = focusables.get(i); int viewLeft = view.getLeft(); int viewRight = view.getRight(); if (left < viewRight && viewLeft < right) { /* * the focusable is in the target area, it is a candidate for * focusing */ final boolean viewIsFullyContained = (left < viewLeft) && (viewRight < right); if (focusCandidate == null) { /* No candidate, take this one */ focusCandidate = view; foundFullyContainedFocusable = viewIsFullyContained; } else { final boolean viewIsCloserToBoundary = (leftFocus && viewLeft < focusCandidate.getLeft()) || (!leftFocus && viewRight > focusCandidate.getRight()); if (foundFullyContainedFocusable) { if (viewIsFullyContained && viewIsCloserToBoundary) { /* * We're dealing with only fully contained views, so * it has to be closer to the boundary to beat our * candidate */ focusCandidate = view; } } else { if (viewIsFullyContained) { /* Any fully contained view beats a partially contained view */ focusCandidate = view; foundFullyContainedFocusable = true; } else if (viewIsCloserToBoundary) { /* * Partially contained view beats another partially * contained view if it's closer */ focusCandidate = view; } } } } } return focusCandidate; } /** * <p>Handles scrolling in response to a "page up/down" shortcut press. This * method will scroll the view by one page left or right and give the focus * to the leftmost/rightmost component in the new visible area. If no * component is a good candidate for focus, this scrollview reclaims the * focus.</p> * * @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT} * to go one page left or {@link android.view.View#FOCUS_RIGHT} * to go one page right * @return true if the key event is consumed by this method, false otherwise */ public boolean pageScroll(int direction) { boolean right = direction == View.FOCUS_RIGHT; int width = getWidth(); if (right) { mTempRect.left = getScrollX() + width; int count = getChildCount(); if (count > 0) { View view = getChildAt(0); if (mTempRect.left + width > view.getRight()) { mTempRect.left = view.getRight() - width; } } } else { mTempRect.left = getScrollX() - width; if (mTempRect.left < 0) { mTempRect.left = 0; } } mTempRect.right = mTempRect.left + width; return scrollAndFocus(direction, mTempRect.left, mTempRect.right); } /** * <p>Handles scrolling in response to a "home/end" shortcut press. This * method will scroll the view to the left or right and give the focus * to the leftmost/rightmost component in the new visible area. If no * component is a good candidate for focus, this scrollview reclaims the * focus.</p> * * @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT} * to go the left of the view or {@link android.view.View#FOCUS_RIGHT} * to go the right * @return true if the key event is consumed by this method, false otherwise */ public boolean fullScroll(int direction) { boolean right = direction == View.FOCUS_RIGHT; int width = getWidth(); mTempRect.left = 0; mTempRect.right = width; if (right) { int count = getChildCount(); if (count > 0) { View view = getChildAt(0); mTempRect.right = view.getRight(); mTempRect.left = mTempRect.right - width; } } return scrollAndFocus(direction, mTempRect.left, mTempRect.right); } /** * <p>Scrolls the view to make the area defined by <code>left</code> and * <code>right</code> visible. This method attempts to give the focus * to a component visible in this area. If no component can be focused in * the new visible area, the focus is reclaimed by this scrollview.</p> * * @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT} * to go left {@link android.view.View#FOCUS_RIGHT} to right * @param left the left offset of the new area to be made visible * @param right the right offset of the new area to be made visible * @return true if the key event is consumed by this method, false otherwise */ private boolean scrollAndFocus(int direction, int left, int right) { boolean handled = true; int width = getWidth(); int containerLeft = getScrollX(); int containerRight = containerLeft + width; boolean goLeft = direction == View.FOCUS_LEFT; View newFocused = findFocusableViewInBounds(goLeft, left, right); if (newFocused == null) { newFocused = this; } if (left >= containerLeft && right <= containerRight) { handled = false; } else { int delta = goLeft ? (left - containerLeft) : (right - containerRight); doScrollX(delta); } if (newFocused != findFocus()) newFocused.requestFocus(direction); return handled; } /** * Handle scrolling in response to a left or right arrow click. * * @param direction The direction corresponding to the arrow key that was * pressed * @return True if we consumed the event, false otherwise */ public boolean arrowScroll(int direction) { View currentFocused = findFocus(); if (currentFocused == this) currentFocused = null; View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, direction); final int maxJump = getMaxScrollAmount(); if (nextFocused != null && isWithinDeltaOfScreen(nextFocused, maxJump)) { nextFocused.getDrawingRect(mTempRect); offsetDescendantRectToMyCoords(nextFocused, mTempRect); int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); doScrollX(scrollDelta); nextFocused.requestFocus(direction); } else { // no new focus int scrollDelta = maxJump; if (direction == View.FOCUS_LEFT && getScrollX() < scrollDelta) { scrollDelta = getScrollX(); } else if (direction == View.FOCUS_RIGHT && getChildCount() > 0) { int daRight = getChildAt(0).getRight(); int screenRight = getScrollX() + getWidth(); if (daRight - screenRight < maxJump) { scrollDelta = daRight - screenRight; } } if (scrollDelta == 0) { return false; } doScrollX(direction == View.FOCUS_RIGHT ? scrollDelta : -scrollDelta); } if (currentFocused != null && currentFocused.isFocused() && isOffScreen(currentFocused)) { // previously focused item still has focus and is off screen, give // it up (take it back to ourselves) // (also, need to temporarily force FOCUS_BEFORE_DESCENDANTS so we are // sure to // get it) final int descendantFocusability = getDescendantFocusability(); // save setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS); requestFocus(); setDescendantFocusability(descendantFocusability); // restore } return true; } /** * @return whether the descendant of this scroll view is scrolled off * screen. */ private boolean isOffScreen(View descendant) { return !isWithinDeltaOfScreen(descendant, 0); } /** * @return whether the descendant of this scroll view is within delta * pixels of being on the screen. */ private boolean isWithinDeltaOfScreen(View descendant, int delta) { descendant.getDrawingRect(mTempRect); offsetDescendantRectToMyCoords(descendant, mTempRect); return (mTempRect.right + delta) >= getScrollX() && (mTempRect.left - delta) <= (getScrollX() + getWidth()); } /** * Smooth scroll by a X delta * * @param delta the number of pixels to scroll by on the X axis */ private void doScrollX(int delta) { if (delta != 0) { if (mSmoothScrollingEnabled) { smoothScrollBy(delta, 0); } else { scrollBy(delta, 0); } } } /** * Like {@link View#scrollBy}, but scroll smoothly instead of immediately. * * @param dx the number of pixels to scroll by on the X axis * @param dy the number of pixels to scroll by on the Y axis */ public final void smoothScrollBy(int dx, int dy) { if (getChildCount() == 0) { // Nothing to do. return; } long duration = AnimationUtils.currentAnimationTimeMillis() - mLastScroll; if (duration > ANIMATED_SCROLL_GAP) { final int width = getWidth() - mPaddingRight - mPaddingLeft; final int right = getChildAt(0).getWidth(); final int maxX = Math.max(0, right - width); final int scrollX = mScrollX; dx = Math.max(0, Math.min(scrollX + dx, maxX)) - scrollX; mScroller.startScroll(scrollX, mScrollY, dx, 0); postInvalidateOnAnimation(); } else { if (!mScroller.isFinished()) { mScroller.abortAnimation(); } scrollBy(dx, dy); } mLastScroll = AnimationUtils.currentAnimationTimeMillis(); } /** * Like {@link #scrollTo}, but scroll smoothly instead of immediately. * * @param x the position where to scroll on the X axis * @param y the position where to scroll on the Y axis */ public final void smoothScrollTo(int x, int y) { smoothScrollBy(x - mScrollX, y - mScrollY); } /** * <p>The scroll range of a scroll view is the overall width of all of its * children.</p> */ @Override protected int computeHorizontalScrollRange() { final int count = getChildCount(); final int contentWidth = getWidth() - mPaddingLeft - mPaddingRight; if (count == 0) { return contentWidth; } int scrollRange = getChildAt(0).getRight(); final int scrollX = mScrollX; final int overscrollRight = Math.max(0, scrollRange - contentWidth); if (scrollX < 0) { scrollRange -= scrollX; } else if (scrollX > overscrollRight) { scrollRange += scrollX - overscrollRight; } return scrollRange; } @Override protected int computeHorizontalScrollOffset() { return Math.max(0, super.computeHorizontalScrollOffset()); } @Override protected void measureChild(View child, int parentWidthMeasureSpec, int parentHeightMeasureSpec) { ViewGroup.LayoutParams lp = child.getLayoutParams(); final int horizontalPadding = mPaddingLeft + mPaddingRight; final int childWidthMeasureSpec = MeasureSpec.makeSafeMeasureSpec( Math.max(0, MeasureSpec.getSize(parentWidthMeasureSpec) - horizontalPadding), MeasureSpec.UNSPECIFIED); final int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec, mPaddingTop + mPaddingBottom, lp.height); child.measure(childWidthMeasureSpec, childHeightMeasureSpec); } @Override protected void measureChildWithMargins(View child, int parentWidthMeasureSpec, int widthUsed, int parentHeightMeasureSpec, int heightUsed) { final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams(); final int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec, mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin + heightUsed, lp.height); final int usedTotal = mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin + widthUsed; final int childWidthMeasureSpec = MeasureSpec.makeSafeMeasureSpec( Math.max(0, MeasureSpec.getSize(parentWidthMeasureSpec) - usedTotal), MeasureSpec.UNSPECIFIED); child.measure(childWidthMeasureSpec, childHeightMeasureSpec); } @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { // This is called at drawing time by ViewGroup. We don't want to // re-show the scrollbars at this point, which scrollTo will do, // so we replicate most of scrollTo here. // // It's a little odd to call onScrollChanged from inside the drawing. // // It is, except when you remember that computeScroll() is used to // animate scrolling. So unless we want to defer the onScrollChanged() // until the end of the animated scrolling, we don't really have a // choice here. // // I agree. The alternative, which I think would be worse, is to post // something and tell the subclasses later. This is bad because there // will be a window where mScrollX/Y is different from what the app // thinks it is. // int oldX = mScrollX; int oldY = mScrollY; int x = mScroller.getCurrX(); int y = mScroller.getCurrY(); if (oldX != x || oldY != y) { final int range = getScrollRange(); final int overscrollMode = getOverScrollMode(); final boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS || (overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0); overScrollBy(x - oldX, y - oldY, oldX, oldY, range, 0, mOverflingDistance, 0, false); onScrollChanged(mScrollX, mScrollY, oldX, oldY); if (canOverscroll) { if (x < 0 && oldX >= 0) { mEdgeGlowLeft.onAbsorb((int) mScroller.getCurrVelocity()); } else if (x > range && oldX <= range) { mEdgeGlowRight.onAbsorb((int) mScroller.getCurrVelocity()); } } } if (!awakenScrollBars()) { postInvalidateOnAnimation(); } } } /** * Scrolls the view to the given child. * * @param child the View to scroll to */ private void scrollToChild(View child) { child.getDrawingRect(mTempRect); /* Offset from child's local coordinates to ScrollView coordinates */ offsetDescendantRectToMyCoords(child, mTempRect); int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); if (scrollDelta != 0) { scrollBy(scrollDelta, 0); } } /** * If rect is off screen, scroll just enough to get it (or at least the * first screen size chunk of it) on screen. * * @param rect The rectangle. * @param immediate True to scroll immediately without animation * @return true if scrolling was performed */ private boolean scrollToChildRect(Rect rect, boolean immediate) { final int delta = computeScrollDeltaToGetChildRectOnScreen(rect); final boolean scroll = delta != 0; if (scroll) { if (immediate) { scrollBy(delta, 0); } else { smoothScrollBy(delta, 0); } } return scroll; } /** * Compute the amount to scroll in the X direction in order to get * a rectangle completely on the screen (or, if taller than the screen, * at least the first screen size chunk of it). * * @param rect The rect. * @return The scroll delta. */ protected int computeScrollDeltaToGetChildRectOnScreen(Rect rect) { if (getChildCount() == 0) return 0; int width = getWidth(); int screenLeft = getScrollX(); int screenRight = screenLeft + width; int fadingEdge = getHorizontalFadingEdgeLength(); // leave room for left fading edge as long as rect isn't at very left if (rect.left > 0) { screenLeft += fadingEdge; } // leave room for right fading edge as long as rect isn't at very right if (rect.right < getChildAt(0).getWidth()) { screenRight -= fadingEdge; } int scrollXDelta = 0; if (rect.right > screenRight && rect.left > screenLeft) { // need to move right to get it in view: move right just enough so // that the entire rectangle is in view (or at least the first // screen size chunk). if (rect.width() > width) { // just enough to get screen size chunk on scrollXDelta += (rect.left - screenLeft); } else { // get entire rect at right of screen scrollXDelta += (rect.right - screenRight); } // make sure we aren't scrolling beyond the end of our content int right = getChildAt(0).getRight(); int distanceToRight = right - screenRight; scrollXDelta = Math.min(scrollXDelta, distanceToRight); } else if (rect.left < screenLeft && rect.right < screenRight) { // need to move right to get it in view: move right just enough so that // entire rectangle is in view (or at least the first screen // size chunk of it). if (rect.width() > width) { // screen size chunk scrollXDelta -= (screenRight - rect.right); } else { // entire rect at left scrollXDelta -= (screenLeft - rect.left); } // make sure we aren't scrolling any further than the left our content scrollXDelta = Math.max(scrollXDelta, -getScrollX()); } return scrollXDelta; } @Override public void requestChildFocus(View child, View focused) { if (focused != null && focused.getRevealOnFocusHint()) { if (!mIsLayoutDirty) { scrollToChild(focused); } else { // The child may not be laid out yet, we can't compute the scroll yet mChildToScrollTo = focused; } } super.requestChildFocus(child, focused); } /** * When looking for focus in children of a scroll view, need to be a little * more careful not to give focus to something that is scrolled off screen. * * This is more expensive than the default {@link android.view.ViewGroup} * implementation, otherwise this behavior might have been made the default. */ @Override protected boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) { // convert from forward / backward notation to up / down / left / right // (ugh). if (direction == View.FOCUS_FORWARD) { direction = View.FOCUS_RIGHT; } else if (direction == View.FOCUS_BACKWARD) { direction = View.FOCUS_LEFT; } final View nextFocus = previouslyFocusedRect == null ? FocusFinder.getInstance().findNextFocus(this, null, direction) : FocusFinder.getInstance().findNextFocusFromRect(this, previouslyFocusedRect, direction); if (nextFocus == null) { return false; } if (isOffScreen(nextFocus)) { return false; } return nextFocus.requestFocus(direction, previouslyFocusedRect); } @Override public boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate) { // offset into coordinate space of this scroll view rectangle.offset(child.getLeft() - child.getScrollX(), child.getTop() - child.getScrollY()); return scrollToChildRect(rectangle, immediate); } @Override public void requestLayout() { mIsLayoutDirty = true; super.requestLayout(); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { int childWidth = 0; int childMargins = 0; if (getChildCount() > 0) { childWidth = getChildAt(0).getMeasuredWidth(); LayoutParams childParams = (LayoutParams) getChildAt(0).getLayoutParams(); childMargins = childParams.leftMargin + childParams.rightMargin; } final int available = r - l - getPaddingLeftWithForeground() - getPaddingRightWithForeground() - childMargins; final boolean forceLeftGravity = (childWidth > available); layoutChildren(l, t, r, b, forceLeftGravity); mIsLayoutDirty = false; // Give a child focus if it needs it if (mChildToScrollTo != null && isViewDescendantOf(mChildToScrollTo, this)) { scrollToChild(mChildToScrollTo); } mChildToScrollTo = null; if (!isLaidOut()) { final int scrollRange = Math.max(0, childWidth - (r - l - mPaddingLeft - mPaddingRight)); if (mSavedState != null) { mScrollX = isLayoutRtl() ? scrollRange - mSavedState.scrollOffsetFromStart : mSavedState.scrollOffsetFromStart; mSavedState = null; } else { if (isLayoutRtl()) { mScrollX = scrollRange - mScrollX; } // mScrollX default value is "0" for LTR } // Don't forget to clamp if (mScrollX > scrollRange) { mScrollX = scrollRange; } else if (mScrollX < 0) { mScrollX = 0; } } // Calling this with the present values causes it to re-claim them scrollTo(mScrollX, mScrollY); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); View currentFocused = findFocus(); if (null == currentFocused || this == currentFocused) return; final int maxJump = mRight - mLeft; if (isWithinDeltaOfScreen(currentFocused, maxJump)) { currentFocused.getDrawingRect(mTempRect); offsetDescendantRectToMyCoords(currentFocused, mTempRect); int scrollDelta = computeScrollDeltaToGetChildRectOnScreen(mTempRect); doScrollX(scrollDelta); } } /** * Return true if child is a descendant of parent, (or equal to the parent). */ private static boolean isViewDescendantOf(View child, View parent) { if (child == parent) { return true; } final ViewParent theParent = child.getParent(); return (theParent instanceof ViewGroup) && isViewDescendantOf((View) theParent, parent); } /** * Fling the scroll view * * @param velocityX The initial velocity in the X direction. Positive * numbers mean that the finger/cursor is moving down the screen, * which means we want to scroll towards the left. */ public void fling(int velocityX) { if (getChildCount() > 0) { int width = getWidth() - mPaddingRight - mPaddingLeft; int right = getChildAt(0).getWidth(); mScroller.fling(mScrollX, mScrollY, velocityX, 0, 0, Math.max(0, right - width), 0, 0, width / 2, 0); final boolean movingRight = velocityX > 0; View currentFocused = findFocus(); View newFocused = findFocusableViewInMyBounds(movingRight, mScroller.getFinalX(), currentFocused); if (newFocused == null) { newFocused = this; } if (newFocused != currentFocused) { newFocused.requestFocus(movingRight ? View.FOCUS_RIGHT : View.FOCUS_LEFT); } postInvalidateOnAnimation(); } } /** * {@inheritDoc} * * <p>This version also clamps the scrolling to the bounds of our child. */ @Override public void scrollTo(int x, int y) { // we rely on the fact the View.scrollBy calls scrollTo. if (getChildCount() > 0) { View child = getChildAt(0); x = clamp(x, getWidth() - mPaddingRight - mPaddingLeft, child.getWidth()); y = clamp(y, getHeight() - mPaddingBottom - mPaddingTop, child.getHeight()); if (x != mScrollX || y != mScrollY) { super.scrollTo(x, y); } } } @Override public void setOverScrollMode(int mode) { if (mode != OVER_SCROLL_NEVER) { if (mEdgeGlowLeft == null) { Context context = getContext(); mEdgeGlowLeft = new EdgeEffect(context); mEdgeGlowRight = new EdgeEffect(context); } } else { mEdgeGlowLeft = null; mEdgeGlowRight = null; } super.setOverScrollMode(mode); } @SuppressWarnings({ "SuspiciousNameCombination" }) @Override public void draw(Canvas canvas) { super.draw(canvas); if (mEdgeGlowLeft != null) { final int scrollX = mScrollX; if (!mEdgeGlowLeft.isFinished()) { final int restoreCount = canvas.save(); final int height = getHeight() - mPaddingTop - mPaddingBottom; canvas.rotate(270); canvas.translate(-height + mPaddingTop, Math.min(0, scrollX)); mEdgeGlowLeft.setSize(height, getWidth()); if (mEdgeGlowLeft.draw(canvas)) { postInvalidateOnAnimation(); } canvas.restoreToCount(restoreCount); } if (!mEdgeGlowRight.isFinished()) { final int restoreCount = canvas.save(); final int width = getWidth(); final int height = getHeight() - mPaddingTop - mPaddingBottom; canvas.rotate(90); canvas.translate(-mPaddingTop, -(Math.max(getScrollRange(), scrollX) + width)); mEdgeGlowRight.setSize(height, width); if (mEdgeGlowRight.draw(canvas)) { postInvalidateOnAnimation(); } canvas.restoreToCount(restoreCount); } } } private static int clamp(int n, int my, int child) { if (my >= child || n < 0) { return 0; } if ((my + n) > child) { return child - my; } return n; } @Override protected void onRestoreInstanceState(Parcelable state) { if (mContext.getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.JELLY_BEAN_MR2) { // Some old apps reused IDs in ways they shouldn't have. // Don't break them, but they don't get scroll state restoration. super.onRestoreInstanceState(state); return; } SavedState ss = (SavedState) state; super.onRestoreInstanceState(ss.getSuperState()); mSavedState = ss; requestLayout(); } @Override protected Parcelable onSaveInstanceState() { if (mContext.getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.JELLY_BEAN_MR2) { // Some old apps reused IDs in ways they shouldn't have. // Don't break them, but they don't get scroll state restoration. return super.onSaveInstanceState(); } Parcelable superState = super.onSaveInstanceState(); SavedState ss = new SavedState(superState); ss.scrollOffsetFromStart = isLayoutRtl() ? -mScrollX : mScrollX; return ss; } /** @hide */ @Override protected void encodeProperties(@NonNull ViewHierarchyEncoder encoder) { super.encodeProperties(encoder); encoder.addProperty("layout:fillViewPort", mFillViewport); } static class SavedState extends BaseSavedState { public int scrollOffsetFromStart; SavedState(Parcelable superState) { super(superState); } public SavedState(Parcel source) { super(source); scrollOffsetFromStart = source.readInt(); } @Override public void writeToParcel(Parcel dest, int flags) { super.writeToParcel(dest, flags); dest.writeInt(scrollOffsetFromStart); } @Override public String toString() { return "HorizontalScrollView.SavedState{" + Integer.toHexString(System.identityHashCode(this)) + " scrollPosition=" + scrollOffsetFromStart + "}"; } 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]; } }; } }