commit bb44c03b1c45c18483121ace5d5b986419f78b6e
author Schneider Victor-tulias <victortulias@google.com> Thu Apr 07 15:25:00 2022 -0700
committer Schneider Victor-tulias <victortulias@google.com> Tue May 03 10:38:23 2022 -0700
tree b2a5d98b39db9b428cd005293dc02d5f38576cc9
parent e73c3075c15fe4bb2e756aef8be947b14c64fc8b

Fix janky overview animation.

Switching to overview shortly after switching to 3-button mode caused a janky animation if the PagedView wasn't properly initialized yet. Moved the animation to a callback.

Fixes: 203632659
Fixes: 223719200
Test: manual
Change-Id: I8a345036c6b7322ae3fa50a23bcb7522f57c8a90

src/com/android/launcher3/PagedView.java

diff --git a/src/com/android/launcher3/PagedView.java b/src/com/android/launcher3/PagedView.java
index 0a1d25c..95a8a2a 100644
--- a/src/com/android/launcher3/PagedView.java
+++ b/src/com/android/launcher3/PagedView.java
@@ -129,7 +129,10 @@
     private boolean mAllowEasyFling;
     protected PagedOrientationHandler mOrientationHandler = PagedOrientationHandler.PORTRAIT;
 
-    protected int[] mPageScrolls;
+    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
@@ -684,14 +687,37 @@
         setMeasuredDimension(widthSize, heightSize);
     }
 
+    /** Returns true iff this PagedView's scroll amounts are initialized to each page index. */
+    protected boolean pageScrollsInitialized() {
+        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 (pageScrollsInitialized()) {
+            onPageScrollsInitialized();
+        }
+    }
+
+    private 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 (mPageScrolls == null || childCount != mPageScrolls.length) {
-            mPageScrolls = new int[childCount];
+        if (!pageScrollsInitialized()) {
+            pageScrolls = new int[childCount];
             pageScrollChanged = true;
         }
 
@@ -701,10 +727,8 @@
 
         if (DEBUG) Log.d(TAG, "PagedView.onLayout()");
 
-        boolean isScrollChanged = getPageScrolls(mPageScrolls, true, SIMPLE_SCROLL_LOGIC);
-        if (isScrollChanged) {
-            pageScrollChanged = true;
-        }
+        pageScrollChanged |= getPageScrolls(pageScrolls, true, SIMPLE_SCROLL_LOGIC);
+        mPageScrolls = pageScrolls;
 
         final LayoutTransition transition = getLayoutTransition();
         // If the transition is running defer updating max scroll, as some empty pages could
@@ -738,6 +762,7 @@
         if (mScroller.isFinished() && pageScrollChanged) {
             setCurrentPage(getNextPage());
         }
+        onPageScrollsInitialized();
     }
 
     /**
@@ -849,8 +874,10 @@
     @Override
     public void onViewRemoved(View child) {
         super.onViewRemoved(child);
-        mCurrentPage = validateNewPage(mCurrentPage);
-        mCurrentScrollOverPage = mCurrentPage;
+        runOnPageScrollsInitialized(() -> {
+            mCurrentPage = validateNewPage(mCurrentPage);
+            mCurrentScrollOverPage = mCurrentPage;
+        });
         dispatchPageCountChanged();
     }
 
@@ -1153,7 +1180,7 @@
     }
 
     public int getScrollForPage(int index) {
-        if (mPageScrolls == null || index >= mPageScrolls.length || index < 0) {
+        if (!pageScrollsInitialized() || index >= mPageScrolls.length || index < 0) {
             return 0;
         } else {
             return mPageScrolls[index];
@@ -1163,7 +1190,7 @@
     // 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 (mPageScrolls == null || index >= mPageScrolls.length || index < 0) {
+        if (!pageScrollsInitialized() || index >= mPageScrolls.length || index < 0) {
             return 0;
         } else {
             View child = getChildAt(index);