From 86ac825061d48d169998485f419208e851ee402c Mon Sep 17 00:00:00 2001
From: Alex Chau <alexchau@google.com>
Date: Tue, 15 Jun 2021 15:09:11 +0100
Subject: [PATCH] Move focused task to front when attaching RecentsView

- Only move focused task it's the first time attaching RecentsView
- Simpily remove and re-add focused task to move it to front

Bug: 192471181
Test: manual
Change-Id: I95b29c39328911beec7fd3d254f7a22be5e10cc1
---
 .../android/quickstep/AbsSwipeUpHandler.java  | 18 ++++++++++--
 .../quickstep/BaseActivityInterface.java      | 13 +++++++++
 .../android/quickstep/views/RecentsView.java  | 29 +++++++++++++++++++
 3 files changed, 57 insertions(+), 3 deletions(-)

diff --git a/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java b/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
index 9180bd026f..bda2b77bb3 100644
--- a/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
+++ b/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
@@ -539,7 +539,7 @@ public abstract class AbsSwipeUpHandler<T extends StatefulActivity<S>,
             @Override
             public void onMotionPauseDetected() {
                 mHasMotionEverBeenPaused = true;
-                maybeUpdateRecentsAttachedState();
+                maybeUpdateRecentsAttachedState(true/* animate */, true/* moveFocusedTask */);
                 performHapticFeedback();
             }
 
@@ -550,18 +550,24 @@ public abstract class AbsSwipeUpHandler<T extends StatefulActivity<S>,
         };
     }
 
-    public void maybeUpdateRecentsAttachedState() {
+    private void maybeUpdateRecentsAttachedState() {
         maybeUpdateRecentsAttachedState(true /* animate */);
     }
 
+    private void maybeUpdateRecentsAttachedState(boolean animate) {
+        maybeUpdateRecentsAttachedState(animate, false /* moveFocusedTask */);
+    }
+
     /**
      * Determines whether to show or hide RecentsView. The window is always
      * synchronized with its corresponding TaskView in RecentsView, so if
      * RecentsView is shown, it will appear to be attached to the window.
      *
      * Note this method has no effect unless the navigation mode is NO_BUTTON.
+     * @param animate whether to animate when attaching RecentsView
+     * @param moveFocusedTask whether to move focused task to front when attaching
      */
-    private void maybeUpdateRecentsAttachedState(boolean animate) {
+    private void maybeUpdateRecentsAttachedState(boolean animate, boolean moveFocusedTask) {
         if (!mDeviceState.isFullyGesturalNavMode() || mRecentsView == null) {
             return;
         }
@@ -580,6 +586,12 @@ public abstract class AbsSwipeUpHandler<T extends StatefulActivity<S>,
         } else {
             recentsAttachedToAppWindow = mHasMotionEverBeenPaused || mIsLikelyToStartNewTask;
         }
+        if (moveFocusedTask && !mAnimationFactory.hasRecentsEverAttachedToAppWindow()
+                && recentsAttachedToAppWindow) {
+            // Only move focused task if RecentsView has never been attached before, to avoid
+            // TaskView jumping to new position as we move the tasks.
+            mRecentsView.moveFocusedTaskToFront();
+        }
         mAnimationFactory.setRecentsAttachedToAppWindow(recentsAttachedToAppWindow, animate);
 
         // Reapply window transform throughout the attach animation, as the animation affects how
diff --git a/quickstep/src/com/android/quickstep/BaseActivityInterface.java b/quickstep/src/com/android/quickstep/BaseActivityInterface.java
index 1412b1add6..389509f978 100644
--- a/quickstep/src/com/android/quickstep/BaseActivityInterface.java
+++ b/quickstep/src/com/android/quickstep/BaseActivityInterface.java
@@ -396,6 +396,10 @@ public abstract class BaseActivityInterface<STATE_TYPE extends BaseState<STATE_T
         default boolean isRecentsAttachedToAppWindow() {
             return false;
         }
+
+        default boolean hasRecentsEverAttachedToAppWindow() {
+            return false;
+        }
     }
 
     class DefaultAnimationFactory implements AnimationFactory {
@@ -405,6 +409,7 @@ public abstract class BaseActivityInterface<STATE_TYPE extends BaseState<STATE_T
         private final Consumer<AnimatorControllerWithResistance> mCallback;
 
         private boolean mIsAttachedToWindow;
+        private boolean mHasEverAttachedToWindow;
 
         DefaultAnimationFactory(Consumer<AnimatorControllerWithResistance> callback) {
             mCallback = callback;
@@ -458,6 +463,9 @@ public abstract class BaseActivityInterface<STATE_TYPE extends BaseState<STATE_T
             }
             mIsAttachedToWindow = attached;
             RecentsView recentsView = mActivity.getOverviewPanel();
+            if (attached) {
+                mHasEverAttachedToWindow = true;
+            }
             Animator fadeAnim = mActivity.getStateManager()
                     .createStateElementAnimation(INDEX_RECENTS_FADE_ANIM, attached ? 1 : 0);
 
@@ -487,6 +495,11 @@ public abstract class BaseActivityInterface<STATE_TYPE extends BaseState<STATE_T
             return mIsAttachedToWindow;
         }
 
+        @Override
+        public boolean hasRecentsEverAttachedToAppWindow() {
+            return mHasEverAttachedToWindow;
+        }
+
         protected void createBackgroundToOverviewAnim(ACTIVITY_TYPE activity, PendingAnimation pa) {
             //  Scale down recents from being full screen to being in overview.
             RecentsView recentsView = activity.getOverviewPanel();
diff --git a/quickstep/src/com/android/quickstep/views/RecentsView.java b/quickstep/src/com/android/quickstep/views/RecentsView.java
index 25b98d7b51..9d10b54f16 100644
--- a/quickstep/src/com/android/quickstep/views/RecentsView.java
+++ b/quickstep/src/com/android/quickstep/views/RecentsView.java
@@ -1111,6 +1111,35 @@ public abstract class RecentsView<ACTIVITY_TYPE extends StatefulActivity<STATE_T
         }
     }
 
+    /**
+     * Moves the focused task to the front of the carousel in tablets, to minimize animation
+     * required to focus the task in grid.
+     */
+    public void moveFocusedTaskToFront() {
+        if (!(mActivity.getDeviceProfile().isTablet && FeatureFlags.ENABLE_OVERVIEW_GRID.get())) {
+            return;
+        }
+
+        TaskView focusedTaskView = getFocusedTaskView();
+        if (focusedTaskView == null) {
+            return;
+        }
+
+        if (indexOfChild(focusedTaskView) != mCurrentPage) {
+            return;
+        }
+
+        int primaryScroll = mOrientationHandler.getPrimaryScroll(this);
+        int currentPageScroll = getScrollForPage(mCurrentPage);
+        mCurrentPageScrollDiff = primaryScroll - currentPageScroll;
+
+        removeView(focusedTaskView);
+        addView(focusedTaskView, mTaskViewStartIndex);
+        setCurrentPage(0);
+
+        updateGridProperties();
+    }
+
     protected void applyLoadPlan(ArrayList<Task> tasks) {
         if (mPendingAnimation != null) {
             mPendingAnimation.addEndListener(success -> applyLoadPlan(tasks));