Removing animation when stripping empty pages, as the animation is
run by LayoutAnimation already

Bug: 151978739
Change-Id: I75b9055c3e862a6813164cce6c1ba7b2fe1f870a
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index a83a694..455eebc 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -760,8 +760,8 @@
                     data.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, -1) : -1;
             if (resultCode == RESULT_CANCELED) {
                 completeTwoStageWidgetDrop(RESULT_CANCELED, appWidgetId, requestArgs);
-                mWorkspace.removeExtraEmptyScreenDelayed(true, exitSpringLoaded,
-                        ON_ACTIVITY_RESULT_ANIMATION_DELAY, false);
+                mWorkspace.removeExtraEmptyScreenDelayed(
+                        ON_ACTIVITY_RESULT_ANIMATION_DELAY, false, exitSpringLoaded);
             } else if (resultCode == RESULT_OK) {
                 addAppWidgetImpl(
                         appWidgetId, requestArgs, null,
@@ -791,15 +791,9 @@
                         "returned from the widget configuration activity.");
                 result = RESULT_CANCELED;
                 completeTwoStageWidgetDrop(result, appWidgetId, requestArgs);
-                final Runnable onComplete = new Runnable() {
-                    @Override
-                    public void run() {
-                        getStateManager().goToState(NORMAL);
-                    }
-                };
-
-                mWorkspace.removeExtraEmptyScreenDelayed(true, onComplete,
-                        ON_ACTIVITY_RESULT_ANIMATION_DELAY, false);
+                mWorkspace.removeExtraEmptyScreenDelayed(
+                        ON_ACTIVITY_RESULT_ANIMATION_DELAY, false,
+                        () -> getStateManager().goToState(NORMAL));
             } else {
                 if (requestArgs.container == LauncherSettings.Favorites.CONTAINER_DESKTOP) {
                     // When the screen id represents an actual screen (as opposed to a rank)
@@ -818,8 +812,8 @@
                         dropLayout.setDropPending(false);
                     }
                 };
-                mWorkspace.removeExtraEmptyScreenDelayed(true, onComplete,
-                        ON_ACTIVITY_RESULT_ANIMATION_DELAY, false);
+                mWorkspace.removeExtraEmptyScreenDelayed(
+                        ON_ACTIVITY_RESULT_ANIMATION_DELAY, false, onComplete);
             }
             return;
         }
@@ -838,12 +832,12 @@
             // Handle custom shortcuts created using ACTION_CREATE_SHORTCUT.
             if (resultCode == RESULT_OK && requestArgs.container != ItemInfo.NO_ID) {
                 completeAdd(requestCode, data, -1, requestArgs);
-                mWorkspace.removeExtraEmptyScreenDelayed(true, exitSpringLoaded,
-                        ON_ACTIVITY_RESULT_ANIMATION_DELAY, false);
+                mWorkspace.removeExtraEmptyScreenDelayed(
+                        ON_ACTIVITY_RESULT_ANIMATION_DELAY, false, exitSpringLoaded);
 
             } else if (resultCode == RESULT_CANCELED) {
-                mWorkspace.removeExtraEmptyScreenDelayed(true, exitSpringLoaded,
-                        ON_ACTIVITY_RESULT_ANIMATION_DELAY, false);
+                mWorkspace.removeExtraEmptyScreenDelayed(
+                        ON_ACTIVITY_RESULT_ANIMATION_DELAY, false, exitSpringLoaded);
             }
         }
 
@@ -1682,7 +1676,7 @@
             };
             completeAddAppWidget(appWidgetId, info, boundWidget,
                     addFlowHandler.getProviderInfo(this));
-            mWorkspace.removeExtraEmptyScreenDelayed(true, onComplete, delay, false);
+            mWorkspace.removeExtraEmptyScreenDelayed(delay, false, onComplete);
         }
     }
 
@@ -2112,7 +2106,7 @@
         }
 
         // Remove the extra empty screen
-        mWorkspace.removeExtraEmptyScreen(false, false);
+        mWorkspace.removeExtraEmptyScreen(false);
     }
 
     /**
diff --git a/src/com/android/launcher3/Workspace.java b/src/com/android/launcher3/Workspace.java
index c42e480..2cc5a22 100644
--- a/src/com/android/launcher3/Workspace.java
+++ b/src/com/android/launcher3/Workspace.java
@@ -29,7 +29,6 @@
 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.LayoutTransition;
-import android.animation.ObjectAnimator;
 import android.animation.ValueAnimator;
 import android.animation.ValueAnimator.AnimatorUpdateListener;
 import android.annotation.SuppressLint;
@@ -125,9 +124,6 @@
 
     private static final boolean ENFORCE_DRAG_EVENT_ORDER = false;
 
-    private static final int SNAP_OFF_EMPTY_SCREEN_DURATION = 400;
-    private static final int FADE_EMPTY_SCREEN_DURATION = 150;
-
     private static final int ADJACENT_SCREEN_DROP_DURATION = 300;
 
     private static final int DEFAULT_PAGE = 0;
@@ -140,7 +136,6 @@
     @Thunk final IntSparseArrayMap<CellLayout> mWorkspaceScreens = new IntSparseArrayMap<>();
     @Thunk final IntArray mScreenOrder = new IntArray();
 
-    @Thunk Runnable mRemoveEmptyScreenRunnable;
     @Thunk boolean mDeferRemoveExtraEmptyScreen = false;
 
     /**
@@ -428,7 +423,7 @@
         }
 
         if (!mDeferRemoveExtraEmptyScreen) {
-            removeExtraEmptyScreen(true, mDragSourceInternal != null);
+            removeExtraEmptyScreen(mDragSourceInternal != null);
         }
 
         updateChildrenLayersEnabled();
@@ -453,8 +448,16 @@
     private void setupLayoutTransition() {
         // We want to show layout transitions when pages are deleted, to close the gap.
         mLayoutTransition = new LayoutTransition();
+
         mLayoutTransition.enableTransitionType(LayoutTransition.DISAPPEARING);
         mLayoutTransition.enableTransitionType(LayoutTransition.CHANGE_DISAPPEARING);
+        // Change the interpolators such that the fade animation plays before the move animation.
+        // This prevents empty adjacent pages to overlay during animation
+        mLayoutTransition.setInterpolator(LayoutTransition.DISAPPEARING,
+                Interpolators.clampToProgress(Interpolators.ACCEL_DEACCEL, 0, 0.5f));
+        mLayoutTransition.setInterpolator(LayoutTransition.CHANGE_DISAPPEARING,
+                Interpolators.clampToProgress(Interpolators.ACCEL_DEACCEL, 0.5f, 1));
+
         mLayoutTransition.disableTransitionType(LayoutTransition.APPEARING);
         mLayoutTransition.disableTransitionType(LayoutTransition.CHANGE_APPEARING);
         setLayoutTransition(mLayoutTransition);
@@ -571,9 +574,6 @@
         boolean lastChildOnScreen = false;
         boolean childOnFinalScreen = false;
 
-        // Cancel any pending removal of empty screen
-        mRemoveEmptyScreenRunnable = null;
-
         if (mDragSourceInternal != null) {
             if (mDragSourceInternal.getChildCount() == 1) {
                 lastChildOnScreen = true;
@@ -624,43 +624,34 @@
         }
     }
 
-    public void removeExtraEmptyScreen(final boolean animate, boolean stripEmptyScreens) {
-        removeExtraEmptyScreenDelayed(animate, null, 0, stripEmptyScreens);
+    public void removeExtraEmptyScreen(boolean stripEmptyScreens) {
+        removeExtraEmptyScreenDelayed(0, stripEmptyScreens, null);
     }
 
-    public void removeExtraEmptyScreenDelayed(final boolean animate, final Runnable onComplete,
-            final int delay, final boolean stripEmptyScreens) {
+    public void removeExtraEmptyScreenDelayed(
+            int delay, boolean stripEmptyScreens, Runnable onComplete) {
         if (mLauncher.isWorkspaceLoading()) {
             // Don't strip empty screens if the workspace is still loading
             return;
         }
 
         if (delay > 0) {
-            postDelayed(new Runnable() {
-                @Override
-                public void run() {
-                    removeExtraEmptyScreenDelayed(animate, onComplete, 0, stripEmptyScreens);
-                }
-            }, delay);
+            postDelayed(
+                    () -> removeExtraEmptyScreenDelayed(0, stripEmptyScreens, onComplete), delay);
             return;
         }
 
         convertFinalScreenToEmptyScreenIfNecessary();
         if (hasExtraEmptyScreen()) {
-            int emptyIndex = mScreenOrder.indexOf(EXTRA_EMPTY_SCREEN_ID);
-            if (getNextPage() == emptyIndex) {
-                snapToPage(getNextPage() - 1, SNAP_OFF_EMPTY_SCREEN_DURATION);
-                fadeAndRemoveEmptyScreen(SNAP_OFF_EMPTY_SCREEN_DURATION, FADE_EMPTY_SCREEN_DURATION,
-                        onComplete, stripEmptyScreens);
-            } else {
-                snapToPage(getNextPage(), 0);
-                fadeAndRemoveEmptyScreen(0, FADE_EMPTY_SCREEN_DURATION,
-                        onComplete, stripEmptyScreens);
-            }
-            return;
-        } else if (stripEmptyScreens) {
-            // If we're not going to strip the empty screens after removing
-            // the extra empty screen, do it right away.
+            removeView(mWorkspaceScreens.get(EXTRA_EMPTY_SCREEN_ID));
+            mWorkspaceScreens.remove(EXTRA_EMPTY_SCREEN_ID);
+            mScreenOrder.removeValue(EXTRA_EMPTY_SCREEN_ID);
+
+            // Update the page indicator to reflect the removed page.
+            showPageIndicatorAtCurrentScroll();
+        }
+
+        if (stripEmptyScreens) {
             stripEmptyScreens();
         }
 
@@ -669,44 +660,6 @@
         }
     }
 
-    private void fadeAndRemoveEmptyScreen(int delay, int duration, final Runnable onComplete,
-            final boolean stripEmptyScreens) {
-        // XXX: Do we need to update LM workspace screens below?
-        final CellLayout cl = mWorkspaceScreens.get(EXTRA_EMPTY_SCREEN_ID);
-
-        mRemoveEmptyScreenRunnable = new Runnable() {
-            @Override
-            public void run() {
-                if (hasExtraEmptyScreen()) {
-                    mWorkspaceScreens.remove(EXTRA_EMPTY_SCREEN_ID);
-                    mScreenOrder.removeValue(EXTRA_EMPTY_SCREEN_ID);
-                    removeView(cl);
-                    if (stripEmptyScreens) {
-                        stripEmptyScreens();
-                    }
-                    // Update the page indicator to reflect the removed page.
-                    showPageIndicatorAtCurrentScroll();
-                }
-            }
-        };
-
-        ObjectAnimator oa = ObjectAnimator.ofFloat(cl, ALPHA, 0f);
-        oa.setDuration(duration);
-        oa.setStartDelay(delay);
-        oa.addListener(new AnimatorListenerAdapter() {
-            @Override
-            public void onAnimationEnd(Animator animation) {
-                if (mRemoveEmptyScreenRunnable != null) {
-                    mRemoveEmptyScreenRunnable.run();
-                }
-                if (onComplete != null) {
-                    onComplete.run();
-                }
-            }
-        });
-        oa.start();
-    }
-
     public boolean hasExtraEmptyScreen() {
         return mWorkspaceScreens.containsKey(EXTRA_EMPTY_SCREEN_ID) && getChildCount() > 1;
     }
@@ -793,8 +746,6 @@
             }
         }
 
-        boolean isInAccessibleDrag = mLauncher.getAccessibilityDelegate().isInAccessibleDrag();
-
         // We enforce at least one page to add new items to. In the case that we remove the last
         // such screen, we convert the last screen to the empty screen
         int minScreens = 1;
@@ -813,7 +764,6 @@
                 removeView(cl);
             } else {
                 // if this is the last screen, convert it to the empty screen
-                mRemoveEmptyScreenRunnable = null;
                 mWorkspaceScreens.put(EXTRA_EMPTY_SCREEN_ID, cl);
                 mScreenOrder.add(EXTRA_EMPTY_SCREEN_ID);
             }