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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.launcher3;
import static com.android.app.animation.Interpolators.SCROLL;
import static com.android.launcher3.compat.AccessibilityManagerCompat.isAccessibilityEnabled;
import static com.android.launcher3.compat.AccessibilityManagerCompat.isObservedEventType;
import static com.android.launcher3.testing.shared.TestProtocol.SCROLL_FINISHED_MESSAGE;
import static com.android.launcher3.touch.OverScroll.OVERSCROLL_DAMP_FACTOR;
import static com.android.launcher3.touch.PagedOrientationHandler.VIEW_SCROLL_BY;
import static com.android.launcher3.touch.PagedOrientationHandler.VIEW_SCROLL_TO;
import android.animation.LayoutTransition;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.os.Bundle;
import android.provider.Settings;
import android.util.AttributeSet;
import android.util.Log;
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.ViewParent;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityNodeInfo;
import android.widget.OverScroller;
import android.widget.ScrollView;
import androidx.annotation.Nullable;
import com.android.launcher3.compat.AccessibilityManagerCompat;
import com.android.launcher3.config.FeatureFlags;
import com.android.launcher3.pageindicators.PageIndicator;
import com.android.launcher3.touch.PagedOrientationHandler;
import com.android.launcher3.touch.PagedOrientationHandler.ChildBounds;
import com.android.launcher3.util.EdgeEffectCompat;
import com.android.launcher3.util.IntSet;
import com.android.launcher3.util.Thunk;
import com.android.launcher3.views.ActivityContext;
import java.util.ArrayList;
import java.util.function.Consumer;
/**
* An abstraction of the original Workspace which supports browsing through a
* sequential list of "pages"
*/
public abstract class PagedView<T extends View & PageIndicator> extends ViewGroup {
private static final String TAG = "PagedView";
private static final boolean DEBUG = false;
public static final boolean DEBUG_FAILED_QUICKSWITCH = false;
public static final int ACTION_MOVE_ALLOW_EASY_FLING = MotionEvent.ACTION_MASK - 1;
public static final int INVALID_PAGE = -1;
protected static final ComputePageScrollsLogic SIMPLE_SCROLL_LOGIC = (v) -> v.getVisibility() != GONE;
private static final float RETURN_TO_ORIGINAL_PAGE_THRESHOLD = 0.33f;
// The page is moved more than halfway, automatically move to the next page on touch up.
private static final float SIGNIFICANT_MOVE_THRESHOLD = 0.4f;
private static final float MAX_SCROLL_PROGRESS = 1.0f;
private boolean mFreeScroll = false;
private int mFlingThresholdVelocity;
private int mEasyFlingThresholdVelocity;
private int mMinFlingVelocity;
private int mMinSnapVelocity;
private int mPageSnapAnimationDuration;
protected boolean mFirstLayout = true;
@ViewDebug.ExportedProperty(category = "launcher")
protected int mCurrentPage;
// Difference between current scroll position and mCurrentPage's page scroll. Used to maintain
// relative scroll position unchanged in updateCurrentPageScroll. Cleared when snapping to a
// page.
protected int mCurrentPageScrollDiff;
// The current page the PagedView is scrolling over on it's way to the destination page.
protected int mCurrentScrollOverPage;
@ViewDebug.ExportedProperty(category = "launcher")
protected int mNextPage = INVALID_PAGE;
protected int mMaxScroll;
protected int mMinScroll;
protected OverScroller mScroller;
private VelocityTracker mVelocityTracker;
protected int mPageSpacing = 0;
private float mDownMotionX;
private float mDownMotionY;
private float mDownMotionPrimary;
private int mLastMotion;
private float mTotalMotion;
// Used in special cases where the fling checks can be relaxed for an intentional gesture
private boolean mAllowEasyFling;
private PagedOrientationHandler mOrientationHandler =
PagedOrientationHandler.DEFAULT;
private final ArrayList<Runnable> mOnPageScrollsInitializedCallbacks = new ArrayList<>();
// We should always check pageScrollsInitialized() is true when using mPageScrolls.
@Nullable protected int[] mPageScrolls = null;
private boolean mIsBeingDragged;
// The amount of movement to begin scrolling
protected int mTouchSlop;
// The amount of movement to begin paging
protected int mPageSlop;
private int mMaximumVelocity;
protected boolean mAllowOverScroll = true;
protected static final int INVALID_POINTER = -1;
protected int mActivePointerId = INVALID_POINTER;
protected boolean mIsPageInTransition = false;
private Runnable mOnPageTransitionEndCallback;
// Page Indicator
@Thunk int mPageIndicatorViewId;
protected T mPageIndicator;
protected final Rect mInsets = new Rect();
protected boolean mIsRtl;
// Similar to the platform implementation of isLayoutValid();
protected boolean mIsLayoutValid;
private int[] mTmpIntPair = new int[2];
protected EdgeEffectCompat mEdgeGlowLeft;
protected EdgeEffectCompat mEdgeGlowRight;
public PagedView(Context context) {
this(context, null);
}
public PagedView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public PagedView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.PagedView, defStyle, 0);
mPageIndicatorViewId = a.getResourceId(R.styleable.PagedView_pageIndicator, -1);
a.recycle();
setHapticFeedbackEnabled(false);
mIsRtl = Utilities.isRtl(getResources());
mScroller = new OverScroller(context, SCROLL);
mCurrentPage = 0;
mCurrentScrollOverPage = 0;
final ViewConfiguration configuration = ViewConfiguration.get(context);
mTouchSlop = configuration.getScaledTouchSlop();
mPageSlop = configuration.getScaledPagingTouchSlop();
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
updateVelocityValues();
initEdgeEffect();
setDefaultFocusHighlightEnabled(false);
setWillNotDraw(false);
}
protected void initEdgeEffect() {
mEdgeGlowLeft = new EdgeEffectCompat(getContext());
mEdgeGlowRight = new EdgeEffectCompat(getContext());
}
public void initParentViews(View parent) {
if (mPageIndicatorViewId > -1) {
mPageIndicator = parent.findViewById(mPageIndicatorViewId);
mPageIndicator.setMarkersCount(getChildCount() / getPanelCount());
}
}
public T getPageIndicator() {
return mPageIndicator;
}
/**
* Returns the index of the currently displayed page. When in free scroll mode, this is the page
* that the user was on before entering free scroll mode (e.g. the home screen page they
* long-pressed on to enter the overview). Try using {@link #getDestinationPage()}
* to get the page the user is currently scrolling over.
*/
public int getCurrentPage() {
return mCurrentPage;
}
/**
* Returns the index of page to be shown immediately afterwards.
*/
public int getNextPage() {
return (mNextPage != INVALID_PAGE) ? mNextPage : mCurrentPage;
}
public int getPageCount() {
return getChildCount();
}
public View getPageAt(int index) {
return getChildAt(index);
}
protected PagedOrientationHandler getPagedOrientationHandler() {
return mOrientationHandler;
}
protected void setOrientationHandler(PagedOrientationHandler orientationHandler) {
this.mOrientationHandler = orientationHandler;
}
/**
* Updates the scroll of the current page immediately to its final scroll position. We use this
* in CustomizePagedView to allow tabs to share the same PagedView while resetting the scroll of
* the previous tab page.
*/
protected void updateCurrentPageScroll() {
// If the current page is invalid, just reset the scroll position to zero
int newPosition = 0;
if (0 <= mCurrentPage && mCurrentPage < getPageCount()) {
newPosition = getScrollForPage(mCurrentPage) + mCurrentPageScrollDiff;
}
mOrientationHandler.setPrimary(this, VIEW_SCROLL_TO, newPosition);
mScroller.startScroll(mScroller.getCurrX(), 0, newPosition - mScroller.getCurrX(), 0);
forceFinishScroller();
}
/**
* Immediately finishes any overscroll effect and jumps to the end of the scroller animation.
*/
public void abortScrollerAnimation() {
mEdgeGlowLeft.finish();
mEdgeGlowRight.finish();
abortScrollerAnimation(true);
}
protected void onScrollerAnimationAborted() {
// No-Op
}
private void abortScrollerAnimation(boolean resetNextPage) {
mScroller.abortAnimation();
onScrollerAnimationAborted();
// We need to clean up the next page here to avoid computeScrollHelper from
// updating current page on the pass.
if (resetNextPage) {
mNextPage = INVALID_PAGE;
pageEndTransition();
}
}
/**
* Immediately finishes any in-progress scroll, maintaining the current position. Also sets
* mNextPage = INVALID_PAGE and calls pageEndTransition().
*/
public void forceFinishScroller() {
mScroller.forceFinished(true);
// We need to clean up the next page here to avoid computeScrollHelper from
// updating current page on the pass.
mNextPage = INVALID_PAGE;
pageEndTransition();
}
private int validateNewPage(int newPage) {
newPage = ensureWithinScrollBounds(newPage);
// Ensure that it is clamped by the actual set of children in all cases
newPage = Utilities.boundToRange(newPage, 0, getPageCount() - 1);
if (getPanelCount() > 1) {
// Always return left most panel as new page
newPage = getLeftmostVisiblePageForIndex(newPage);
}
return newPage;
}
/**
* In most cases where panelCount is 1, this method will just return the page index that was
* passed in.
* But for example when two panel home is enabled we might need the leftmost visible page index
* because that page is the current page.
*/
public int getLeftmostVisiblePageForIndex(int pageIndex) {
int panelCount = getPanelCount();
return pageIndex - pageIndex % panelCount;
}
/**
* Returns the number of pages that are shown at the same time.
*/
protected int getPanelCount() {
return 1;
}
/**
* Returns an IntSet with the indices of the currently visible pages
*/
public IntSet getVisiblePageIndices() {
return getPageIndices(mCurrentPage);
}
/**
* In case the panelCount is 1 this just returns the same page index in an IntSet.
* But in cases where the panelCount > 1 this will return all the page indices that belong
* together, i.e. on the Workspace they are next to each other and shown at the same time.
*/
private IntSet getPageIndices(int pageIndex) {
// we want to make sure the pageIndex is the leftmost page
pageIndex = getLeftmostVisiblePageForIndex(pageIndex);
IntSet pageIndices = new IntSet();
int panelCount = getPanelCount();
int pageCount = getPageCount();
for (int page = pageIndex; page < pageIndex + panelCount && page < pageCount; page++) {
pageIndices.add(page);
}
return pageIndices;
}
/**
* Returns an IntSet with the indices of the neighbour pages that are in the focus direction.
*/
private IntSet getNeighbourPageIndices(int focus) {
int panelCount = getPanelCount();
// getNextPage is more reliable than getCurrentPage
int currentPage = getNextPage();
int nextPage;
if (focus == View.FOCUS_LEFT) {
nextPage = currentPage - panelCount;
} else if (focus == View.FOCUS_RIGHT) {
nextPage = currentPage + panelCount;
} else {
// no neighbours to other directions
return new IntSet();
}
nextPage = validateNewPage(nextPage);
if (nextPage == currentPage) {
// We reached the end of the pages
return new IntSet();
}
return getPageIndices(nextPage);
}
/**
* Executes the callback against each visible page
*/
public void forEachVisiblePage(Consumer<View> callback) {
getVisiblePageIndices().forEach(pageIndex -> {
View page = getPageAt(pageIndex);
if (page != null) {
callback.accept(page);
}
});
}
/**
* Returns true if the view is on one of the current pages, false otherwise.
*/
public boolean isVisible(View child) {
return isVisible(indexOfChild(child));
}
/**
* Returns true if the page with the given index is currently visible, false otherwise.
*/
private boolean isVisible(int pageIndex) {
return getLeftmostVisiblePageForIndex(pageIndex) == mCurrentPage;
}
/**
* @return The closest page to the provided page that is within mMinScrollX and mMaxScrollX.
*/
private int ensureWithinScrollBounds(int page) {
int dir = !mIsRtl ? 1 : - 1;
int currScroll = getScrollForPage(page);
int prevScroll;
while (currScroll < mMinScroll) {
page += dir;
prevScroll = currScroll;
currScroll = getScrollForPage(page);
if (currScroll <= prevScroll) {
Log.e(TAG, "validateNewPage: failed to find a page > mMinScrollX");
break;
}
}
while (currScroll > mMaxScroll) {
page -= dir;
prevScroll = currScroll;
currScroll = getScrollForPage(page);
if (currScroll >= prevScroll) {
Log.e(TAG, "validateNewPage: failed to find a page < mMaxScrollX");
break;
}
}
return page;
}
public void setCurrentPage(int currentPage) {
setCurrentPage(currentPage, INVALID_PAGE);
}
/**
* Sets the current page.
*/
public void setCurrentPage(int currentPage, int overridePrevPage) {
if (!mScroller.isFinished()) {
abortScrollerAnimation(true);
}
// don't introduce any checks like mCurrentPage == currentPage here-- if we change the
// the default
if (getChildCount() == 0) {
return;
}
int prevPage = overridePrevPage != INVALID_PAGE ? overridePrevPage : mCurrentPage;
mCurrentPage = validateNewPage(currentPage);
mCurrentScrollOverPage = mCurrentPage;
updateCurrentPageScroll();
notifyPageSwitchListener(prevPage);
invalidate();
}
/**
* Should be called whenever the page changes. In the case of a scroll, we wait until the page
* has settled.
*/
protected void notifyPageSwitchListener(int prevPage) {
updatePageIndicator();
}
private void updatePageIndicator() {
if (mPageIndicator != null) {
mPageIndicator.setActiveMarker(getNextPage());
}
}
protected void pageBeginTransition() {
if (!mIsPageInTransition) {
mIsPageInTransition = true;
onPageBeginTransition();
}
}
protected void pageEndTransition() {
if (mIsPageInTransition && !mIsBeingDragged && mScroller.isFinished()
&& (!isShown() || (mEdgeGlowLeft.isFinished() && mEdgeGlowRight.isFinished()))) {
mIsPageInTransition = false;
onPageEndTransition();
}
}
@Override
public void onVisibilityAggregated(boolean isVisible) {
pageEndTransition();
super.onVisibilityAggregated(isVisible);
}
protected boolean isPageInTransition() {
return mIsPageInTransition;
}
/**
* Called when the page starts moving as part of the scroll. Subclasses can override this
* to provide custom behavior during animation.
*/
protected void onPageBeginTransition() {
}
/**
* Called when the page ends moving as part of the scroll. Subclasses can override this
* to provide custom behavior during animation.
*/
protected void onPageEndTransition() {
mCurrentPageScrollDiff = 0;
AccessibilityManagerCompat.sendTestProtocolEventToTest(getContext(),
SCROLL_FINISHED_MESSAGE);
AccessibilityManagerCompat.sendCustomAccessibilityEvent(getPageAt(mCurrentPage),
AccessibilityEvent.TYPE_VIEW_FOCUSED, null);
if (mOnPageTransitionEndCallback != null) {
mOnPageTransitionEndCallback.run();
mOnPageTransitionEndCallback = null;
}
}
/**
* Sets a callback to run once when the scrolling finishes. If there is currently
* no page in transition, then the callback is called immediately.
*/
public void setOnPageTransitionEndCallback(@Nullable Runnable callback) {
if (mIsPageInTransition || callback == null) {
mOnPageTransitionEndCallback = callback;
} else {
callback.run();
}
}
@Override
public void scrollTo(int x, int y) {
x = Utilities.boundToRange(x,
mOrientationHandler.getPrimaryValue(mMinScroll, 0), mMaxScroll);
y = Utilities.boundToRange(y,
mOrientationHandler.getPrimaryValue(0, mMinScroll), mMaxScroll);
super.scrollTo(x, y);
}
private void sendScrollAccessibilityEvent() {
if (isObservedEventType(getContext(), AccessibilityEvent.TYPE_VIEW_SCROLLED)) {
if (mCurrentPage != getNextPage()) {
AccessibilityEvent ev =
AccessibilityEvent.obtain(AccessibilityEvent.TYPE_VIEW_SCROLLED);
ev.setScrollable(true);
ev.setScrollX(getScrollX());
ev.setScrollY(getScrollY());
mOrientationHandler.setMaxScroll(ev, mMaxScroll);
sendAccessibilityEventUnchecked(ev);
}
}
}
protected void announcePageForAccessibility() {
if (isAccessibilityEnabled(getContext())) {
// Notify the user when the page changes
announceForAccessibility(getCurrentPageDescription());
}
}
protected boolean computeScrollHelper() {
if (mScroller.computeScrollOffset()) {
// Don't bother scrolling if the page does not need to be moved
int oldPos = mOrientationHandler.getPrimaryScroll(this);
int newPos = mScroller.getCurrX();
if (oldPos != newPos) {
mOrientationHandler.setPrimary(this, VIEW_SCROLL_TO, mScroller.getCurrX());
}
if (mAllowOverScroll) {
if (newPos < mMinScroll && oldPos >= mMinScroll) {
mEdgeGlowLeft.onAbsorb((int) mScroller.getCurrVelocity());
abortScrollerAnimation(false);
onEdgeAbsorbingScroll();
} else if (newPos > mMaxScroll && oldPos <= mMaxScroll) {
mEdgeGlowRight.onAbsorb((int) mScroller.getCurrVelocity());
abortScrollerAnimation(false);
onEdgeAbsorbingScroll();
}
}
// If the scroller has scrolled to the final position and there is no edge effect, then
// finish the scroller to skip waiting for additional settling
int finalPos = mOrientationHandler.getPrimaryValue(mScroller.getFinalX(),
mScroller.getFinalY());
if (newPos == finalPos && mEdgeGlowLeft.isFinished() && mEdgeGlowRight.isFinished()) {
abortScrollerAnimation(false);
}
invalidate();
return true;
} else if (mNextPage != INVALID_PAGE) {
sendScrollAccessibilityEvent();
int prevPage = mCurrentPage;
mCurrentPage = validateNewPage(mNextPage);
mCurrentScrollOverPage = mCurrentPage;
mNextPage = INVALID_PAGE;
notifyPageSwitchListener(prevPage);
// We don't want to trigger a page end moving unless the page has settled
// and the user has stopped scrolling
if (!mIsBeingDragged) {
pageEndTransition();
}
if (canAnnouncePageDescription()) {
announcePageForAccessibility();
}
}
return false;
}
@Override
public void computeScroll() {
computeScrollHelper();
}
public int getExpectedHeight() {
return getMeasuredHeight();
}
public int getNormalChildHeight() {
return getExpectedHeight() - getPaddingTop() - getPaddingBottom()
- mInsets.top - mInsets.bottom;
}
public int getExpectedWidth() {
return getMeasuredWidth();
}
public int getNormalChildWidth() {
return getExpectedWidth() - getPaddingLeft() - getPaddingRight()
- mInsets.left - mInsets.right;
}
private void updateVelocityValues() {
Resources res = getResources();
mFlingThresholdVelocity = res.getDimensionPixelSize(R.dimen.fling_threshold_velocity);
mEasyFlingThresholdVelocity =
res.getDimensionPixelSize(R.dimen.easy_fling_threshold_velocity);
mMinFlingVelocity = res.getDimensionPixelSize(R.dimen.min_fling_velocity);
mMinSnapVelocity = res.getDimensionPixelSize(R.dimen.min_page_snap_velocity);
mPageSnapAnimationDuration = res.getInteger(R.integer.config_pageSnapAnimationDuration);
onVelocityValuesUpdated();
}
protected void onVelocityValuesUpdated() {
// Overridden in RecentsView
}
@Override
protected void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
updateVelocityValues();
}
@Override
public void requestLayout() {
mIsLayoutValid = false;
super.requestLayout();
}
@Override
public void forceLayout() {
mIsLayoutValid = false;
super.forceLayout();
}
private int getPageWidthSize(int widthSize) {
// It's necessary to add the padding back because it is remove when measuring children,
// like when MeasureSpec.getSize in CellLayout.
return (widthSize - mInsets.left - mInsets.right - getPaddingLeft() - getPaddingRight())
/ getPanelCount() + getPaddingLeft() + getPaddingRight();
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
if (getChildCount() == 0) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
return;
}
// We measure the dimensions of the PagedView to be larger than the pages so that when we
// zoom out (and scale down), the view is still contained in the parent
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int widthSize = MeasureSpec.getSize(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int heightSize = MeasureSpec.getSize(heightMeasureSpec);
if (widthMode == MeasureSpec.UNSPECIFIED || heightMode == MeasureSpec.UNSPECIFIED) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
return;
}
// Return early if we aren't given a proper dimension
if (widthSize <= 0 || heightSize <= 0) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
return;
}
// The children are given the same width and height as the workspace
// unless they were set to WRAP_CONTENT
if (DEBUG) Log.d(TAG, "PagedView.onMeasure(): " + widthSize + ", " + heightSize);
int myWidthSpec = MeasureSpec.makeMeasureSpec(
getPageWidthSize(widthSize), MeasureSpec.EXACTLY);
int myHeightSpec = MeasureSpec.makeMeasureSpec(
heightSize - mInsets.top - mInsets.bottom, MeasureSpec.EXACTLY);
// measureChildren takes accounts for content padding, we only need to care about extra
// space due to insets.
measureChildren(myWidthSpec, myHeightSpec);
setMeasuredDimension(widthSize, heightSize);
}
/** Returns true iff this PagedView's scroll amounts are initialized to each page index. */
protected boolean isPageScrollsInitialized() {
return mPageScrolls != null && mPageScrolls.length == getChildCount();
}
/**
* Queues the given callback to be run once {@code mPageScrolls} has been initialized.
*/
public void runOnPageScrollsInitialized(Runnable callback) {
mOnPageScrollsInitializedCallbacks.add(callback);
if (isPageScrollsInitialized()) {
onPageScrollsInitialized();
}
}
protected void onPageScrollsInitialized() {
for (Runnable callback : mOnPageScrollsInitializedCallbacks) {
callback.run();
}
mOnPageScrollsInitializedCallbacks.clear();
}
@SuppressLint("DrawAllocation")
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
mIsLayoutValid = true;
final int childCount = getChildCount();
int[] pageScrolls = mPageScrolls;
boolean pageScrollChanged = false;
if (!isPageScrollsInitialized()) {
pageScrolls = new int[childCount];
pageScrollChanged = true;
}
if (DEBUG) Log.d(TAG, "PagedView.onLayout()");
pageScrollChanged |= getPageScrolls(pageScrolls, true, SIMPLE_SCROLL_LOGIC);
mPageScrolls = pageScrolls;
if (childCount == 0) {
onPageScrollsInitialized();
return;
}
final LayoutTransition transition = getLayoutTransition();
// If the transition is running defer updating max scroll, as some empty pages could
// still be present, and a max scroll change could cause sudden jumps in scroll.
if (transition != null && transition.isRunning()) {
transition.addTransitionListener(new LayoutTransition.TransitionListener() {
@Override
public void startTransition(LayoutTransition transition, ViewGroup container,
View view, int transitionType) { }
@Override
public void endTransition(LayoutTransition transition, ViewGroup container,
View view, int transitionType) {
// Wait until all transitions are complete.
if (!transition.isRunning()) {
transition.removeTransitionListener(this);
updateMinAndMaxScrollX();
}
}
});
} else {
updateMinAndMaxScrollX();
}
if (mFirstLayout && mCurrentPage >= 0 && mCurrentPage < childCount) {
updateCurrentPageScroll();
mFirstLayout = false;
}
if (mScroller.isFinished() && pageScrollChanged) {
// TODO(b/246283207): Remove logging once root cause of flake detected.
if (Utilities.isRunningInTestHarness() && !(this instanceof Workspace)) {
Log.d("b/246283207", this.getClass().getSimpleName() + "#onLayout() -> "
+ "if(mScroller.isFinished() && pageScrollChanged) -> getNextPage(): "
+ getNextPage() + ", getScrollForPage(getNextPage()): "
+ getScrollForPage(getNextPage()));
}
setCurrentPage(getNextPage());
}
onPageScrollsInitialized();
}
/**
* Initializes {@code outPageScrolls} with scroll positions for view at that index. The length
* of {@code outPageScrolls} should be same as the the childCount
*/
protected boolean getPageScrolls(int[] outPageScrolls, boolean layoutChildren,
ComputePageScrollsLogic scrollLogic) {
final int childCount = getChildCount();
final int startIndex = mIsRtl ? childCount - 1 : 0;
final int endIndex = mIsRtl ? -1 : childCount;
final int delta = mIsRtl ? -1 : 1;
final int pageCenter = mOrientationHandler.getCenterForPage(this, mInsets);
final int scrollOffsetStart = mOrientationHandler.getScrollOffsetStart(this, mInsets);
final int scrollOffsetEnd = mOrientationHandler.getScrollOffsetEnd(this, mInsets);
boolean pageScrollChanged = false;
int panelCount = getPanelCount();
for (int i = startIndex, childStart = scrollOffsetStart; i != endIndex; i += delta) {
final View child = getPageAt(i);
if (scrollLogic.shouldIncludeView(child)) {
ChildBounds bounds = mOrientationHandler.getChildBounds(child, childStart,
pageCenter, layoutChildren);
final int primaryDimension = bounds.primaryDimension;
final int childPrimaryEnd = bounds.childPrimaryEnd;
// In case the pages are of different width, align the page to left edge for non-RTL
// or right edge for RTL.
final int pageScroll =
mIsRtl ? childPrimaryEnd - scrollOffsetEnd : childStart - scrollOffsetStart;
if (outPageScrolls[i] != pageScroll) {
pageScrollChanged = true;
outPageScrolls[i] = pageScroll;
}
childStart += primaryDimension + getChildGap(i, i + delta);
// This makes sure that the space is added after the page, not after each panel
int lastPanel = mIsRtl ? 0 : panelCount - 1;
if (i % panelCount == lastPanel) {
childStart += mPageSpacing;
}
}
}
if (panelCount > 1) {
for (int i = 0; i < childCount; i++) {
// In case we have multiple panels, always use left most panel's page scroll for all
// panels on the screen.
int adjustedScroll = outPageScrolls[getLeftmostVisiblePageForIndex(i)];
if (outPageScrolls[i] != adjustedScroll) {
outPageScrolls[i] = adjustedScroll;
pageScrollChanged = true;
}
}
}
return pageScrollChanged;
}
protected int getChildGap(int fromIndex, int toIndex) {
return 0;
}
protected void updateMinAndMaxScrollX() {
mMinScroll = computeMinScroll();
mMaxScroll = computeMaxScroll();
}
protected int computeMinScroll() {
return 0;
}
protected int computeMaxScroll() {
int childCount = getChildCount();
if (childCount > 0) {
final int index = mIsRtl ? 0 : childCount - 1;
return getScrollForPage(index);
} else {
return 0;
}
}
public void setPageSpacing(int pageSpacing) {
mPageSpacing = pageSpacing;
requestLayout();
}
public int getPageSpacing() {
return mPageSpacing;
}
private void dispatchPageCountChanged() {
if (mPageIndicator != null) {
mPageIndicator.setMarkersCount(getChildCount() / getPanelCount());
}
// This ensures that when children are added, they get the correct transforms / alphas
// in accordance with any scroll effects.
invalidate();
}
@Override
public void onViewAdded(View child) {
super.onViewAdded(child);
dispatchPageCountChanged();
}
@Override
public void onViewRemoved(View child) {
super.onViewRemoved(child);
runOnPageScrollsInitialized(() -> {
mCurrentPage = validateNewPage(mCurrentPage);
mCurrentScrollOverPage = mCurrentPage;
});
dispatchPageCountChanged();
}
protected int getChildOffset(int index) {
if (index < 0 || index > getChildCount() - 1) return 0;
View pageAtIndex = getPageAt(index);
return mOrientationHandler.getChildStart(pageAtIndex);
}
protected int getChildVisibleSize(int index) {
View layout = getPageAt(index);
return mOrientationHandler.getMeasuredSize(layout);
}
@Override
public boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate) {
int page = indexOfChild(child);
if (!isVisible(page) || !mScroller.isFinished()) {
if (immediate) {
setCurrentPage(page);
} else {
snapToPage(page);
}
return true;
}
return false;
}
@Override
protected boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) {
int focusablePage;
if (mNextPage != INVALID_PAGE) {
focusablePage = mNextPage;
} else {
focusablePage = mCurrentPage;
}
View v = getPageAt(focusablePage);
if (v != null) {
return v.requestFocus(direction, previouslyFocusedRect);
}
return false;
}
@Override
public boolean dispatchUnhandledMove(View focused, int direction) {
if (super.dispatchUnhandledMove(focused, direction)) {
return true;
}
if (mIsRtl) {
if (direction == View.FOCUS_LEFT) {
direction = View.FOCUS_RIGHT;
} else if (direction == View.FOCUS_RIGHT) {
direction = View.FOCUS_LEFT;
}
}
int currentPage = getNextPage();
int closestNeighbourIndex = -1;
int closestNeighbourDistance = Integer.MAX_VALUE;
// Find the closest neighbour page
for (int neighbourPageIndex : getNeighbourPageIndices(direction)) {
int distance = Math.abs(neighbourPageIndex - currentPage);
if (closestNeighbourDistance > distance) {
closestNeighbourDistance = distance;
closestNeighbourIndex = neighbourPageIndex;
}
}
if (closestNeighbourIndex != -1) {
View page = getPageAt(closestNeighbourIndex);
snapToPage(closestNeighbourIndex);
page.requestFocus(direction);
return true;
}
return false;
}
@Override
public void addFocusables(ArrayList<View> views, int direction, int focusableMode) {
if (getDescendantFocusability() == FOCUS_BLOCK_DESCENDANTS) {
return;
}
// nextPage is more reliable when multiple control movements have been done in a short
// period of time
getPageIndices(getNextPage())
.addAll(getNeighbourPageIndices(direction))
.forEach(pageIndex ->
getPageAt(pageIndex).addFocusables(views, direction, focusableMode));
}
/**
* If one of our descendant views decides that it could be focused now, only
* pass that along if it's on the current page.
*
* This happens when live folders requery, and if they're off page, they
* end up calling requestFocus, which pulls it on page.
*/
@Override
public void focusableViewAvailable(View focused) {
View current = getPageAt(mCurrentPage);
View v = focused;
while (true) {
if (v == current) {
super.focusableViewAvailable(focused);
return;
}
if (v == this) {
return;
}
ViewParent parent = v.getParent();
if (parent instanceof View) {
v = (View)v.getParent();
} else {
return;
}
}
}
/**
* {@inheritDoc}
*/
@Override
public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) {
if (disallowIntercept) {
// We need to make sure to cancel our long press if
// a scrollable widget takes over touch events
cancelCurrentPageLongPress();
}
super.requestDisallowInterceptTouchEvent(disallowIntercept);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
/*
* This method JUST determines whether we want to intercept the motion.
* If we return true, onTouchEvent will be called and we do the actual
* scrolling there.
*/
// Skip touch handling if there are no pages to swipe
if (getChildCount() <= 0) return false;
acquireVelocityTrackerAndAddMovement(ev);
/*
* 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;
}
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 their original down touch.
*/
if (mActivePointerId != INVALID_POINTER) {
determineScrollingStart(ev);
}
// if mActivePointerId is INVALID_POINTER, then we must have missed an ACTION_DOWN
// event. in that case, treat the first occurrence of a move event as a ACTION_DOWN
// i.e. fall through to the next case (don't break)
// (We sometimes miss ACTION_DOWN events in Workspace because it ignores all events
// while it's small- this was causing a crash before we checked for INVALID_POINTER)
break;
}
case MotionEvent.ACTION_DOWN: {
final float x = ev.getX();
final float y = ev.getY();
// Remember location of down touch
mDownMotionX = x;
mDownMotionY = y;
mDownMotionPrimary = mOrientationHandler.getPrimaryDirection(ev, 0);
mLastMotion = (int) mDownMotionPrimary;
mTotalMotion = 0;
mAllowEasyFling = false;
mActivePointerId = ev.getPointerId(0);
updateIsBeingDraggedOnTouchDown(ev);
break;
}
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
resetTouchState();
break;
case MotionEvent.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
releaseVelocityTracker();
break;
}
/*
* The only time we want to intercept motion events is if we are in the
* drag mode.
*/
return mIsBeingDragged;
}
/**
* If being flinged and user touches the screen, initiate drag; otherwise don't.
*/
protected void updateIsBeingDraggedOnTouchDown(MotionEvent ev) {
// mScroller.isFinished should be false when being flinged.
final int xDist = Math.abs(mScroller.getFinalX() - mScroller.getCurrX());
final boolean finishedScrolling = (mScroller.isFinished() || xDist < mPageSlop / 3);
if (finishedScrolling) {
mIsBeingDragged = false;
if (!mScroller.isFinished() && !mFreeScroll) {
setCurrentPage(getNextPage());
pageEndTransition();
}
mIsBeingDragged = !mEdgeGlowLeft.isFinished() || !mEdgeGlowRight.isFinished();
} else {
mIsBeingDragged = true;
}
// Catch the edge effect if it is active.
float displacement = mOrientationHandler.getSecondaryValue(ev.getX(), ev.getY())
/ mOrientationHandler.getSecondaryValue(getWidth(), getHeight());
if (!mEdgeGlowLeft.isFinished()) {
mEdgeGlowLeft.onPullDistance(0f, 1f - displacement);
}
if (!mEdgeGlowRight.isFinished()) {
mEdgeGlowRight.onPullDistance(0f, displacement, ev);
}
}
public boolean isHandlingTouch() {
return mIsBeingDragged;
}
protected void determineScrollingStart(MotionEvent ev) {
determineScrollingStart(ev, 1.0f);
}
/*
* Determines if we should change the touch state to start scrolling after the
* user moves their touch point too far.
*/
protected void determineScrollingStart(MotionEvent ev, float touchSlopScale) {
// Disallow scrolling if we don't have a valid pointer index
final int pointerIndex = ev.findPointerIndex(mActivePointerId);
if (pointerIndex == -1) return;
final float primaryDirection = mOrientationHandler.getPrimaryDirection(ev, pointerIndex);
final int diff = (int) Math.abs(primaryDirection - mLastMotion);
final int touchSlop = Math.round(touchSlopScale * mTouchSlop);
boolean moved = diff > touchSlop || ev.getAction() == ACTION_MOVE_ALLOW_EASY_FLING;
if (moved) {
// Scroll if the user moved far enough along the X axis
mIsBeingDragged = true;
mTotalMotion += Math.abs(mLastMotion - primaryDirection);
mLastMotion = (int) primaryDirection;
pageBeginTransition();
// Stop listening for things like pinches.
requestDisallowInterceptTouchEvent(true);
}
}
protected void cancelCurrentPageLongPress() {
// Try canceling the long press. It could also have been scheduled
// by a distant descendant, so use the mAllowLongPress flag to block
// everything
forEachVisiblePage(View::cancelLongPress);
}
protected float getScrollProgress(int screenCenter, View v, int page) {
final int halfScreenSize = getMeasuredWidth() / 2;
int delta = screenCenter - (getScrollForPage(page) + halfScreenSize);
int panelCount = getPanelCount();
int pageCount = getChildCount();
int adjacentPage = page + panelCount;
if ((delta < 0 && !mIsRtl) || (delta > 0 && mIsRtl)) {
adjacentPage = page - panelCount;
}
final int totalDistance;
if (adjacentPage < 0 || adjacentPage > pageCount - 1) {
totalDistance = (v.getMeasuredWidth() + mPageSpacing) * panelCount;
} else {
totalDistance = Math.abs(getScrollForPage(adjacentPage) - getScrollForPage(page));
}
float scrollProgress = delta / (totalDistance * 1.0f);
scrollProgress = Math.min(scrollProgress, MAX_SCROLL_PROGRESS);
scrollProgress = Math.max(scrollProgress, -MAX_SCROLL_PROGRESS);
return scrollProgress;
}
public int getScrollForPage(int index) {
if (!isPageScrollsInitialized() || index >= mPageScrolls.length || index < 0) {
return 0;
} else {
return mPageScrolls[index];
}
}
// While layout transitions are occurring, a child's position may stray from its baseline
// position. This method returns the magnitude of this stray at any given time.
public int getLayoutTransitionOffsetForPage(int index) {
if (!isPageScrollsInitialized() || index >= mPageScrolls.length || index < 0) {
return 0;
} else {
View child = getChildAt(index);
int scrollOffset = mIsRtl ? getPaddingRight() : getPaddingLeft();
int baselineX = mPageScrolls[index] + scrollOffset;
return (int) (child.getX() - baselineX);
}
}
public void setEnableFreeScroll(boolean freeScroll) {
if (mFreeScroll == freeScroll) {
return;
}
boolean wasFreeScroll = mFreeScroll;
mFreeScroll = freeScroll;
if (mFreeScroll) {
setCurrentPage(getNextPage());
} else if (wasFreeScroll) {
if (getScrollForPage(getNextPage()) != getScrollX()) {
snapToPage(getNextPage());
}
}
}
protected void setEnableOverscroll(boolean enable) {
mAllowOverScroll = enable;
}
protected boolean isSignificantMove(float absoluteDelta, int pageOrientedSize) {
return absoluteDelta > pageOrientedSize * SIGNIFICANT_MOVE_THRESHOLD;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
// Skip touch handling if there are no pages to swipe
if (getChildCount() <= 0) return false;
acquireVelocityTrackerAndAddMovement(ev);
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
updateIsBeingDraggedOnTouchDown(ev);
/*
* If being flinged and user touches, stop the fling. isFinished
* will be false if being flinged.
*/
if (!mScroller.isFinished()) {
abortScrollerAnimation(false);
}
// Remember where the motion event started
mDownMotionX = ev.getX();
mDownMotionY = ev.getY();
mDownMotionPrimary = mOrientationHandler.getPrimaryDirection(ev, 0);
mLastMotion = (int) mDownMotionPrimary;
mTotalMotion = 0;
mAllowEasyFling = false;
mActivePointerId = ev.getPointerId(0);
if (mIsBeingDragged) {
pageBeginTransition();
}
break;
case ACTION_MOVE_ALLOW_EASY_FLING:
// Start scrolling immediately
determineScrollingStart(ev);
mAllowEasyFling = true;
break;
case MotionEvent.ACTION_MOVE:
if (mIsBeingDragged) {
// Scroll to follow the motion event
final int pointerIndex = ev.findPointerIndex(mActivePointerId);
if (pointerIndex == -1) return true;
int oldScroll = mOrientationHandler.getPrimaryScroll(this);
int dx = (int) ev.getX(pointerIndex);
int dy = (int) ev.getY(pointerIndex);
int direction = mOrientationHandler.getPrimaryValue(dx, dy);
int delta = mLastMotion - direction;
int width = getWidth();
int height = getHeight();
float size = mOrientationHandler.getPrimaryValue(width, height);
float displacement = (width == 0 || height == 0) ? 0
: (float) mOrientationHandler.getSecondaryValue(dx, dy)
/ mOrientationHandler.getSecondaryValue(width, height);
mTotalMotion += Math.abs(delta);
if (mAllowOverScroll) {
int consumed = 0;
if (delta < 0 && mEdgeGlowRight.getDistance() != 0f) {
consumed = Math.round(size *
mEdgeGlowRight.onPullDistance(delta / size, displacement, ev));
} else if (delta > 0 && mEdgeGlowLeft.getDistance() != 0f) {
consumed = Math.round(-size *
mEdgeGlowLeft.onPullDistance(-delta / size, 1 - displacement, ev));
}
delta -= consumed;
}
delta /= mOrientationHandler.getPrimaryScale(this);
// Only scroll and update mLastMotionX if we have moved some discrete amount. We
// keep the remainder because we are actually testing if we've moved from the last
// scrolled position (which is discrete).
mLastMotion = direction;
if (delta != 0) {
mOrientationHandler.setPrimary(this, VIEW_SCROLL_BY, delta);
if (mAllowOverScroll) {
final float pulledToX = oldScroll + delta;
if (pulledToX < mMinScroll) {
mEdgeGlowLeft.onPullDistance(-delta / size, 1.f - displacement, ev);
if (!mEdgeGlowRight.isFinished()) {
mEdgeGlowRight.onRelease(ev);
}
} else if (pulledToX > mMaxScroll) {
mEdgeGlowRight.onPullDistance(delta / size, displacement, ev);
if (!mEdgeGlowLeft.isFinished()) {
mEdgeGlowLeft.onRelease(ev);
}
}
if (!mEdgeGlowLeft.isFinished() || !mEdgeGlowRight.isFinished()) {
postInvalidateOnAnimation();
}
}
} else {
awakenScrollBars();
}
} else {
determineScrollingStart(ev);
}
break;
case MotionEvent.ACTION_UP:
if (mIsBeingDragged) {
final int activePointerId = mActivePointerId;
final int pointerIndex = ev.findPointerIndex(activePointerId);
if (pointerIndex == -1) return true;
final float primaryDirection = mOrientationHandler.getPrimaryDirection(ev,
pointerIndex);
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int velocity = (int) mOrientationHandler.getPrimaryVelocity(velocityTracker,
mActivePointerId);
float delta = primaryDirection - mDownMotionPrimary;
View current = getPageAt(mCurrentPage);
if (current == null) {
Log.e(TAG, "current page was null. this should not happen.");
return true;
}
int pageOrientedSize = (int) (mOrientationHandler.getMeasuredSize(current)
* mOrientationHandler.getPrimaryScale(this));
boolean isSignificantMove = isSignificantMove(Math.abs(delta), pageOrientedSize);
mTotalMotion += Math.abs(mLastMotion - primaryDirection);
boolean passedSlop = mAllowEasyFling || mTotalMotion > mPageSlop;
boolean isFling = passedSlop && shouldFlingForVelocity(velocity);
boolean isDeltaLeft = mIsRtl ? delta > 0 : delta < 0;
boolean isVelocityLeft = mIsRtl ? velocity > 0 : velocity < 0;
if (DEBUG_FAILED_QUICKSWITCH && !isFling && mAllowEasyFling) {
Log.d("Quickswitch", "isFling=false vel=" + velocity
+ " threshold=" + mEasyFlingThresholdVelocity);
}
if (!mFreeScroll) {
// In the case that the page is moved far to one direction and then is flung
// in the opposite direction, we use a threshold to determine whether we should
// just return to the starting page, or if we should skip one further.
boolean returnToOriginalPage = false;
if (Math.abs(delta) > pageOrientedSize * RETURN_TO_ORIGINAL_PAGE_THRESHOLD &&
Math.signum(velocity) != Math.signum(delta) && isFling) {
returnToOriginalPage = true;
}
int finalPage;
// We give flings precedence over large moves, which is why we short-circuit our
// test for a large move if a fling has been registered. That is, a large
// move to the left and fling to the right will register as a fling to the right.
if (((isSignificantMove && !isDeltaLeft && !isFling) ||
(isFling && !isVelocityLeft)) && mCurrentPage > 0) {
finalPage = returnToOriginalPage
? mCurrentPage : mCurrentPage - getPanelCount();
runOnPageScrollsInitialized(
() -> snapToPageWithVelocity(finalPage, velocity));
} else if (((isSignificantMove && isDeltaLeft && !isFling) ||
(isFling && isVelocityLeft)) &&
mCurrentPage < getChildCount() - 1) {
finalPage = returnToOriginalPage
? mCurrentPage : mCurrentPage + getPanelCount();
runOnPageScrollsInitialized(
() -> snapToPageWithVelocity(finalPage, velocity));
} else {
runOnPageScrollsInitialized(this::snapToDestination);
}
} else {
if (!mScroller.isFinished()) {
abortScrollerAnimation(true);
}
int initialScroll = mOrientationHandler.getPrimaryScroll(this);
int maxScroll = mMaxScroll;
int minScroll = mMinScroll;
if (((initialScroll >= maxScroll) && (isVelocityLeft || !isFling)) ||
((initialScroll <= minScroll) && (!isVelocityLeft || !isFling))) {
mScroller.springBack(initialScroll, 0, minScroll, maxScroll, 0, 0);
mNextPage = getDestinationPage();
} else {
int velocity1 = -velocity;
// Continue a scroll or fling in progress
mScroller.fling(initialScroll, 0, velocity1, 0, minScroll, maxScroll, 0, 0,
Math.round(getWidth() * 0.5f * OVERSCROLL_DAMP_FACTOR), 0);
int finalPos = mScroller.getFinalX();
mNextPage = getDestinationPage(finalPos);
runOnPageScrollsInitialized(this::onNotSnappingToPageInFreeScroll);
}
invalidate();
}
mEdgeGlowLeft.onFlingVelocity(velocity);
mEdgeGlowRight.onFlingVelocity(velocity);
}
mEdgeGlowLeft.onRelease(ev);
mEdgeGlowRight.onRelease(ev);
// End any intermediate reordering states
resetTouchState();
break;
case MotionEvent.ACTION_CANCEL:
if (mIsBeingDragged) {
runOnPageScrollsInitialized(this::snapToDestination);
}
mEdgeGlowLeft.onRelease(ev);
mEdgeGlowRight.onRelease(ev);
resetTouchState();
break;
case MotionEvent.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
releaseVelocityTracker();
break;
}
return true;
}
protected void onNotSnappingToPageInFreeScroll() { }
/**
* Called when the view edges absorb part of the scroll. Subclasses can override this
* to provide custom behavior during animation.
*/
protected void onEdgeAbsorbingScroll() {
}
/**
* Called when the current page closest to the center of the screen changes as part of the
* scroll. Subclasses can override this to provide custom behavior during scroll.
*/
protected void onScrollOverPageChanged() {
}
protected boolean shouldFlingForVelocity(int velocity) {
float threshold = mAllowEasyFling ? mEasyFlingThresholdVelocity : mFlingThresholdVelocity;
return Math.abs(velocity) > threshold;
}
protected void resetTouchState() {
releaseVelocityTracker();
mIsBeingDragged = false;
mActivePointerId = INVALID_POINTER;
}
@Override
public boolean onGenericMotionEvent(MotionEvent event) {
if ((event.getSource() & InputDevice.SOURCE_CLASS_POINTER) != 0) {
switch (event.getAction()) {
case MotionEvent.ACTION_SCROLL: {
// Handle mouse (or ext. device) by shifting the page depending on the scroll
final float vscroll;
final float hscroll;
if ((event.getMetaState() & KeyEvent.META_SHIFT_ON) != 0) {
vscroll = 0;
hscroll = event.getAxisValue(MotionEvent.AXIS_VSCROLL);
} else {
vscroll = -event.getAxisValue(MotionEvent.AXIS_VSCROLL);
hscroll = event.getAxisValue(MotionEvent.AXIS_HSCROLL);
}
if (!canScroll(Math.abs(vscroll), Math.abs(hscroll))) {
return false;
}
if (hscroll != 0 || vscroll != 0) {
boolean isForwardScroll = mIsRtl ? (hscroll < 0 || vscroll < 0)
: (hscroll > 0 || vscroll > 0);
if (isForwardScroll) {
scrollRight();
} else {
scrollLeft();
}
return true;
}
}
}
}
return super.onGenericMotionEvent(event);
}
/**
* Returns true if the paged view can scroll for the provided vertical and horizontal
* scroll values
*/
protected boolean canScroll(float absVScroll, float absHScroll) {
ActivityContext ac = ActivityContext.lookupContext(getContext());
return (ac == null || AbstractFloatingView.getTopOpenView(ac) == null);
}
private void acquireVelocityTrackerAndAddMovement(MotionEvent ev) {
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);
}
private void releaseVelocityTracker() {
if (mVelocityTracker != null) {
mVelocityTracker.clear();
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}
private void onSecondaryPointerUp(MotionEvent ev) {
final int pointerIndex = ev.getActionIndex();
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;
mDownMotionPrimary = mOrientationHandler.getPrimaryDirection(ev, newPointerIndex);
mLastMotion = (int) mDownMotionPrimary;
mActivePointerId = ev.getPointerId(newPointerIndex);
if (mVelocityTracker != null) {
mVelocityTracker.clear();
}
}
}
@Override
public void requestChildFocus(View child, View focused) {
super.requestChildFocus(child, focused);
if (!shouldHandleRequestChildFocus(child)) {
return;
}
// In case the device is controlled by a controller, mCurrentPage isn't updated properly
// which results in incorrect navigation
int nextPage = getNextPage();
if (nextPage != mCurrentPage) {
setCurrentPage(nextPage);
}
int page = indexOfChild(child);
if (page >= 0 && !isVisible(page) && !isInTouchMode()) {
snapToPage(page);
}
}
protected boolean shouldHandleRequestChildFocus(View child) {
return true;
}
public int getDestinationPage() {
return getDestinationPage(mOrientationHandler.getPrimaryScroll(this));
}
protected int getDestinationPage(int primaryScroll) {
return getPageNearestToCenterOfScreen(primaryScroll);
}
public int getPageNearestToCenterOfScreen() {
return getPageNearestToCenterOfScreen(mOrientationHandler.getPrimaryScroll(this));
}
private int getPageNearestToCenterOfScreen(int primaryScroll) {
int screenCenter = getScreenCenter(primaryScroll);
int minDistanceFromScreenCenter = Integer.MAX_VALUE;
int minDistanceFromScreenCenterIndex = -1;
final int childCount = getChildCount();
for (int i = 0; i < childCount; ++i) {
int distanceFromScreenCenter = Math.abs(
getDisplacementFromScreenCenter(i, screenCenter));
if (distanceFromScreenCenter < minDistanceFromScreenCenter) {
minDistanceFromScreenCenter = distanceFromScreenCenter;
minDistanceFromScreenCenterIndex = i;
}
}
return minDistanceFromScreenCenterIndex;
}
private int getDisplacementFromScreenCenter(int childIndex, int screenCenter) {
int childSize = getChildVisibleSize(childIndex);
int halfChildSize = (childSize / 2);
int childCenter = getChildOffset(childIndex) + halfChildSize;
return childCenter - screenCenter;
}
protected int getDisplacementFromScreenCenter(int childIndex) {
int primaryScroll = mOrientationHandler.getPrimaryScroll(this);
int screenCenter = getScreenCenter(primaryScroll);
return getDisplacementFromScreenCenter(childIndex, screenCenter);
}
protected int getScreenCenter(int primaryScroll) {
float primaryScale = mOrientationHandler.getPrimaryScale(this);
float primaryPivot = mOrientationHandler.getPrimaryValue(getPivotX(), getPivotY());
int pageOrientationSize = mOrientationHandler.getMeasuredSize(this);
return Math.round(primaryScroll + (pageOrientationSize / 2f - primaryPivot) / primaryScale
+ primaryPivot);
}
protected void snapToDestination() {
snapToPage(getDestinationPage(), getSnapAnimationDuration());
}
// We want the duration of the page snap animation to be influenced by the distance that
// the screen has to travel, however, we don't want this duration to be effected in a
// purely linear fashion. Instead, we use this method to moderate the effect that the distance
// of travel has on the overall snap duration.
private float distanceInfluenceForSnapDuration(float f) {
f -= 0.5f; // center the values about 0.
f *= 0.3f * Math.PI / 2.0f;
return (float) Math.sin(f);
}
protected boolean snapToPageWithVelocity(int whichPage, int velocity) {
whichPage = validateNewPage(whichPage);
int halfScreenSize = mOrientationHandler.getMeasuredSize(this) / 2;
final int newLoc = getScrollForPage(whichPage);
int delta = newLoc - mOrientationHandler.getPrimaryScroll(this);
int duration = 0;
if (Math.abs(velocity) < mMinFlingVelocity) {
// If the velocity is low enough, then treat this more as an automatic page advance
// as opposed to an apparent physical response to flinging
return snapToPage(whichPage, getSnapAnimationDuration());
}
// Here we compute a "distance" that will be used in the computation of the overall
// snap duration. This is a function of the actual distance that needs to be traveled;
// we keep this value close to half screen size in order to reduce the variance in snap
// duration as a function of the distance the page needs to travel.
float distanceRatio = Math.min(1f, 1.0f * Math.abs(delta) / (2 * halfScreenSize));
float distance = halfScreenSize + halfScreenSize *
distanceInfluenceForSnapDuration(distanceRatio);
velocity = Math.abs(velocity);
velocity = Math.max(mMinSnapVelocity, velocity);
// we want the page's snap velocity to approximately match the velocity at which the
// user flings, so we scale the duration by a value near to the derivative of the scroll
// interpolator at zero, ie. 5. We use 4 to make it a little slower.
duration = 4 * Math.round(1000 * Math.abs(distance / velocity));
return snapToPage(whichPage, delta, duration);
}
protected int getSnapAnimationDuration() {
return mPageSnapAnimationDuration;
}
public boolean snapToPage(int whichPage) {
return snapToPage(whichPage, getSnapAnimationDuration());
}
public boolean snapToPageImmediately(int whichPage) {
return snapToPage(whichPage, getSnapAnimationDuration(), true);
}
public boolean snapToPage(int whichPage, int duration) {
return snapToPage(whichPage, duration, false);
}
protected boolean snapToPage(int whichPage, int duration, boolean immediate) {
whichPage = validateNewPage(whichPage);
int newLoc = getScrollForPage(whichPage);
final int delta = newLoc - mOrientationHandler.getPrimaryScroll(this);
return snapToPage(whichPage, delta, duration, immediate);
}
protected boolean snapToPage(int whichPage, int delta, int duration) {
return snapToPage(whichPage, delta, duration, false);
}
protected boolean snapToPage(int whichPage, int delta, int duration, boolean immediate) {
if (mFirstLayout) {
setCurrentPage(whichPage);
return false;
}
if (FeatureFlags.IS_STUDIO_BUILD && !Utilities.isRunningInTestHarness()) {
duration *= Settings.Global.getFloat(getContext().getContentResolver(),
Settings.Global.WINDOW_ANIMATION_SCALE, 1);
}
whichPage = validateNewPage(whichPage);
mNextPage = whichPage;
awakenScrollBars(duration);
if (immediate) {
duration = 0;
} else if (duration == 0) {
duration = Math.abs(delta);
}
if (duration != 0) {
pageBeginTransition();
}
if (!mScroller.isFinished()) {
abortScrollerAnimation(false);
}
mScroller.startScroll(mOrientationHandler.getPrimaryScroll(this), 0, delta, 0, duration);
updatePageIndicator();
// Trigger a compute() to finish switching pages if necessary
if (immediate) {
computeScroll();
pageEndTransition();
}
invalidate();
return Math.abs(delta) > 0;
}
public boolean scrollLeft() {
if (getNextPage() > 0) {
snapToPage(getNextPage() - getPanelCount());
return true;
}
return mAllowOverScroll;
}
public boolean scrollRight() {
if (getNextPage() < getChildCount() - 1) {
snapToPage(getNextPage() + getPanelCount());
return true;
}
return mAllowOverScroll;
}
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
if (mScroller.isFinished()) {
// This was not caused by the scroller, skip it.
return;
}
int newDestinationPage = getDestinationPage();
if (newDestinationPage >= 0 && newDestinationPage != mCurrentScrollOverPage) {
mCurrentScrollOverPage = newDestinationPage;
onScrollOverPageChanged();
}
}
@Override
public CharSequence getAccessibilityClassName() {
// Some accessibility services have special logic for ScrollView. Since we provide same
// accessibility info as ScrollView, inform the service to handle use the same way.
return ScrollView.class.getName();
}
protected boolean isPageOrderFlipped() {
return false;
}
/* Accessibility */
@SuppressWarnings("deprecation")
@Override
public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
super.onInitializeAccessibilityNodeInfo(info);
final boolean pagesFlipped = isPageOrderFlipped();
info.setScrollable(getPageCount() > 0);
int primaryScroll = mOrientationHandler.getPrimaryScroll(this);
if (getCurrentPage() < getPageCount() - getPanelCount()
|| (getCurrentPage() == getPageCount() - getPanelCount()
&& primaryScroll != getScrollForPage(getPageCount() - getPanelCount()))) {
info.addAction(pagesFlipped ?
AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_BACKWARD
: AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_FORWARD);
info.addAction(mIsRtl ?
AccessibilityNodeInfo.AccessibilityAction.ACTION_PAGE_LEFT
: AccessibilityNodeInfo.AccessibilityAction.ACTION_PAGE_RIGHT);
}
if (getCurrentPage() > 0
|| (getCurrentPage() == 0 && primaryScroll != getScrollForPage(0))) {
info.addAction(pagesFlipped ?
AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_FORWARD
: AccessibilityNodeInfo.AccessibilityAction.ACTION_SCROLL_BACKWARD);
info.addAction(mIsRtl ?
AccessibilityNodeInfo.AccessibilityAction.ACTION_PAGE_RIGHT
: AccessibilityNodeInfo.AccessibilityAction.ACTION_PAGE_LEFT);
}
// Accessibility-wise, PagedView doesn't support long click, so disabling it.
// Besides disabling the accessibility long-click, this also prevents this view from getting
// accessibility focus.
info.setLongClickable(false);
info.removeAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_LONG_CLICK);
}
@Override
public void sendAccessibilityEvent(int eventType) {
// Don't let the view send real scroll events.
if (eventType != AccessibilityEvent.TYPE_VIEW_SCROLLED) {
super.sendAccessibilityEvent(eventType);
}
}
@Override
public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
super.onInitializeAccessibilityEvent(event);
event.setScrollable(mAllowOverScroll || getPageCount() > 1);
}
@Override
public boolean performAccessibilityAction(int action, Bundle arguments) {
if (super.performAccessibilityAction(action, arguments)) {
return true;
}
final boolean pagesFlipped = isPageOrderFlipped();
switch (action) {
case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD: {
if (pagesFlipped ? scrollLeft() : scrollRight()) {
return true;
}
} break;
case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD: {
if (pagesFlipped ? scrollRight() : scrollLeft()) {
return true;
}
} break;
case android.R.id.accessibilityActionPageRight: {
if (!mIsRtl) {
return scrollRight();
} else {
return scrollLeft();
}
}
case android.R.id.accessibilityActionPageLeft: {
if (!mIsRtl) {
return scrollLeft();
} else {
return scrollRight();
}
}
}
return false;
}
protected boolean canAnnouncePageDescription() {
return true;
}
protected String getCurrentPageDescription() {
return getContext().getString(R.string.default_scroll_format,
getNextPage() + 1, getChildCount());
}
protected float getDownMotionX() {
return mDownMotionX;
}
protected float getDownMotionY() {
return mDownMotionY;
}
protected interface ComputePageScrollsLogic {
boolean shouldIncludeView(View view);
}
public int[] getVisibleChildrenRange() {
float visibleLeft = 0;
float visibleRight = visibleLeft + getMeasuredWidth();
float scaleX = getScaleX();
if (scaleX < 1 && scaleX > 0) {
float mid = getMeasuredWidth() / 2;
visibleLeft = mid - ((mid - visibleLeft) / scaleX);
visibleRight = mid + ((visibleRight - mid) / scaleX);
}
int leftChild = -1;
int rightChild = -1;
final int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
final View child = getPageAt(i);
float left = child.getLeft() + child.getTranslationX() - getScrollX();
if (left <= visibleRight && (left + child.getMeasuredWidth()) >= visibleLeft) {
if (leftChild == -1) {
leftChild = i;
}
rightChild = i;
}
}
mTmpIntPair[0] = leftChild;
mTmpIntPair[1] = rightChild;
return mTmpIntPair;
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
drawEdgeEffect(canvas);
pageEndTransition();
}
protected void drawEdgeEffect(Canvas canvas) {
if (mAllowOverScroll && (!mEdgeGlowRight.isFinished() || !mEdgeGlowLeft.isFinished())) {
final int width = getWidth();
final int height = getHeight();
if (!mEdgeGlowLeft.isFinished()) {
final int restoreCount = canvas.save();
canvas.rotate(-90);
canvas.translate(-height, Math.min(mMinScroll, getScrollX()));
mEdgeGlowLeft.setSize(height, width);
if (mEdgeGlowLeft.draw(canvas)) {
postInvalidateOnAnimation();
}
canvas.restoreToCount(restoreCount);
}
if (!mEdgeGlowRight.isFinished()) {
final int restoreCount = canvas.save();
canvas.rotate(90, width, 0);
canvas.translate(width, -(Math.max(mMaxScroll, getScrollX())));
mEdgeGlowRight.setSize(height, width);
if (mEdgeGlowRight.draw(canvas)) {
postInvalidateOnAnimation();
}
canvas.restoreToCount(restoreCount);
}
}
}
}