From 51433debcd25541f29614f0ef141e4f8e084ecd4 Mon Sep 17 00:00:00 2001
From: Schneider Victor-tulias <victortulias@google.com>
Date: Wed, 21 Aug 2024 14:29:07 -0400
Subject: [PATCH] Polish transition between desktop mode and overview

Fixing desktop task in place along the x-axis and animating its background's alpha to more smoothly handle the transition.

Flag: com.android.launcher3.enable_desktop_task_alpha_animation
Fixes: 320307666
Test: swiped to and from desktop mode and overview
Change-Id: I38d62d0c966733f96c2f4d4ecfa4a9418039fd48
---
 aconfig/launcher.aconfig                      | 10 ++++
 .../android/quickstep/AbsSwipeUpHandler.java  | 18 +++++--
 .../quickstep/BaseActivityInterface.java      | 31 +++++++++---
 .../util/RecentsAtomicAnimationFactory.java   |  9 +++-
 .../android/quickstep/views/RecentsView.java  | 49 ++++++++++++++++---
 .../com/android/quickstep/views/TaskView.kt   | 22 +++++++--
 6 files changed, 115 insertions(+), 24 deletions(-)

diff --git a/aconfig/launcher.aconfig b/aconfig/launcher.aconfig
index be8ebbbdfc..dbcf49cd92 100644
--- a/aconfig/launcher.aconfig
+++ b/aconfig/launcher.aconfig
@@ -339,3 +339,13 @@ flag {
     description: "Change fast scroller to a lettered list"
     bug: "358673724"
 }
+
+flag {
+    name: "enable_desktop_task_alpha_animation"
+    namespace: "launcher"
+    description: "Enables the animation of the desktop task's background view"
+    bug: "320307666"
+    metadata {
+      purpose: PURPOSE_BUGFIX
+    }
+}
diff --git a/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java b/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
index 5392b70703..3d944422cf 100644
--- a/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
+++ b/quickstep/src/com/android/quickstep/AbsSwipeUpHandler.java
@@ -734,11 +734,18 @@ public abstract class AbsSwipeUpHandler<T extends RecentsViewContainer,
     }
 
     private void maybeUpdateRecentsAttachedState() {
-        maybeUpdateRecentsAttachedState(true /* animate */);
+        maybeUpdateRecentsAttachedState(/* animate= */ true);
     }
 
     protected void maybeUpdateRecentsAttachedState(boolean animate) {
-        maybeUpdateRecentsAttachedState(animate, false /* moveRunningTask */);
+        maybeUpdateRecentsAttachedState(animate, /* moveRunningTask= */ false);
+    }
+
+    protected void maybeUpdateRecentsAttachedState(boolean animate, boolean moveRunningTask) {
+        maybeUpdateRecentsAttachedState(
+                animate,
+                moveRunningTask,
+                mRecentsView != null && mRecentsView.shouldUpdateRunningTaskAlpha());
     }
 
     /**
@@ -749,8 +756,10 @@ public abstract class AbsSwipeUpHandler<T extends RecentsViewContainer,
      * Note this method has no effect unless the navigation mode is NO_BUTTON.
      * @param animate whether to animate when attaching RecentsView
      * @param moveRunningTask whether to move running task to front when attaching
+     * @param updateRunningTaskAlpha Whether to update the running task's attached alpha
      */
-    private void maybeUpdateRecentsAttachedState(boolean animate, boolean moveRunningTask) {
+    private void maybeUpdateRecentsAttachedState(
+            boolean animate, boolean moveRunningTask, boolean updateRunningTaskAlpha) {
         if ((!mDeviceState.isFullyGesturalNavMode() && !mGestureState.isTrackpadGesture())
                 || mRecentsView == null) {
             return;
@@ -781,7 +790,8 @@ public abstract class AbsSwipeUpHandler<T extends RecentsViewContainer,
             // TaskView jumping to new position as we move the tasks.
             mRecentsView.moveRunningTaskToFront();
         }
-        mAnimationFactory.setRecentsAttachedToAppWindow(recentsAttachedToAppWindow, animate);
+        mAnimationFactory.setRecentsAttachedToAppWindow(
+                recentsAttachedToAppWindow, animate, updateRunningTaskAlpha);
 
         // Reapply window transform throughout the attach animation, as the animation affects how
         // much the window is bound by overscroll (vs moving freely).
diff --git a/quickstep/src/com/android/quickstep/BaseActivityInterface.java b/quickstep/src/com/android/quickstep/BaseActivityInterface.java
index 293944dca4..87038439bf 100644
--- a/quickstep/src/com/android/quickstep/BaseActivityInterface.java
+++ b/quickstep/src/com/android/quickstep/BaseActivityInterface.java
@@ -21,11 +21,13 @@ import static com.android.app.animation.Interpolators.LINEAR;
 import static com.android.launcher3.MotionEventsUtils.isTrackpadMultiFingerSwipe;
 import static com.android.quickstep.AbsSwipeUpHandler.RECENTS_ATTACH_DURATION;
 import static com.android.quickstep.GestureState.GestureEndTarget.LAST_TASK;
+import static com.android.quickstep.util.RecentsAtomicAnimationFactory.INDEX_RECENTS_ATTACHED_ALPHA_ANIM;
 import static com.android.quickstep.util.RecentsAtomicAnimationFactory.INDEX_RECENTS_FADE_ANIM;
 import static com.android.quickstep.util.RecentsAtomicAnimationFactory.INDEX_RECENTS_TRANSLATE_X_ANIM;
 import static com.android.quickstep.views.RecentsView.ADJACENT_PAGE_HORIZONTAL_OFFSET;
 import static com.android.quickstep.views.RecentsView.FULLSCREEN_PROGRESS;
 import static com.android.quickstep.views.RecentsView.RECENTS_SCALE_PROPERTY;
+import static com.android.quickstep.views.RecentsView.RUNNING_TASK_ATTACH_ALPHA;
 import static com.android.quickstep.views.RecentsView.TASK_SECONDARY_TRANSLATION;
 
 import android.animation.Animator;
@@ -187,8 +189,10 @@ public abstract class BaseActivityInterface<STATE_TYPE extends BaseState<STATE_T
          * @param attached Whether to show RecentsView alongside the app window. If false, recents
          *                 will be hidden by some property we can animate, e.g. alpha.
          * @param animate Whether to animate recents to/from its new attached state.
+         * @param updateRunningTaskAlpha Whether to update the running task's attached alpha
          */
-        default void setRecentsAttachedToAppWindow(boolean attached, boolean animate) { }
+        default void setRecentsAttachedToAppWindow(
+                boolean attached, boolean animate, boolean updateRunningTaskAlpha) { }
 
         default boolean isRecentsAttachedToAppWindow() {
             return false;
@@ -253,12 +257,14 @@ public abstract class BaseActivityInterface<STATE_TYPE extends BaseState<STATE_T
             // (because we set the animation as the current state animation), so we reapply the
             // attached state here as well to ensure recents is shown/hidden appropriately.
             if (DisplayController.getNavigationMode(mActivity) == NavigationMode.NO_BUTTON) {
-                setRecentsAttachedToAppWindow(mIsAttachedToWindow, false);
+                setRecentsAttachedToAppWindow(
+                        mIsAttachedToWindow, false, recentsView.shouldUpdateRunningTaskAlpha());
             }
         }
 
         @Override
-        public void setRecentsAttachedToAppWindow(boolean attached, boolean animate) {
+        public void setRecentsAttachedToAppWindow(
+                boolean attached, boolean animate, boolean updateRunningTaskAlpha) {
             if (mIsAttachedToWindow == attached && animate) {
                 return;
             }
@@ -266,6 +272,10 @@ public abstract class BaseActivityInterface<STATE_TYPE extends BaseState<STATE_T
                     .cancelStateElementAnimation(INDEX_RECENTS_FADE_ANIM);
             mActivity.getStateManager()
                     .cancelStateElementAnimation(INDEX_RECENTS_TRANSLATE_X_ANIM);
+            if (updateRunningTaskAlpha) {
+                mActivity.getStateManager()
+                        .cancelStateElementAnimation(INDEX_RECENTS_ATTACHED_ALPHA_ANIM);
+            }
 
             AnimatorSet animatorSet = new AnimatorSet();
             animatorSet.addListener(new AnimatorListenerAdapter() {
@@ -280,19 +290,28 @@ public abstract class BaseActivityInterface<STATE_TYPE extends BaseState<STATE_T
 
             long animationDuration = animate ? RECENTS_ATTACH_DURATION : 0;
             Animator fadeAnim = mActivity.getStateManager()
-                    .createStateElementAnimation(INDEX_RECENTS_FADE_ANIM, attached ? 1 : 0);
+                    .createStateElementAnimation(INDEX_RECENTS_FADE_ANIM, attached ? 1f : 0f);
             fadeAnim.setInterpolator(attached ? INSTANT : ACCELERATE_2);
             fadeAnim.setDuration(animationDuration);
             animatorSet.play(fadeAnim);
 
             float fromTranslation = ADJACENT_PAGE_HORIZONTAL_OFFSET.get(
                     mActivity.getOverviewPanel());
-            float toTranslation = attached ? 0 : 1;
-
+            float toTranslation = attached ? 0f : 1f;
             Animator translationAnimator = mActivity.getStateManager().createStateElementAnimation(
                     INDEX_RECENTS_TRANSLATE_X_ANIM, fromTranslation, toTranslation);
             translationAnimator.setDuration(animationDuration);
             animatorSet.play(translationAnimator);
+
+            if (updateRunningTaskAlpha) {
+                float fromAlpha = RUNNING_TASK_ATTACH_ALPHA.get(mActivity.getOverviewPanel());
+                float toAlpha = attached ? 1f : 0f;
+                Animator runningTaskAttachAlphaAnimator = mActivity.getStateManager()
+                        .createStateElementAnimation(
+                                INDEX_RECENTS_ATTACHED_ALPHA_ANIM, fromAlpha, toAlpha);
+                runningTaskAttachAlphaAnimator.setDuration(animationDuration);
+                animatorSet.play(runningTaskAttachAlphaAnimator);
+            }
             animatorSet.start();
         }
 
diff --git a/quickstep/src/com/android/quickstep/util/RecentsAtomicAnimationFactory.java b/quickstep/src/com/android/quickstep/util/RecentsAtomicAnimationFactory.java
index 0b05c2e7c1..63fe017023 100644
--- a/quickstep/src/com/android/quickstep/util/RecentsAtomicAnimationFactory.java
+++ b/quickstep/src/com/android/quickstep/util/RecentsAtomicAnimationFactory.java
@@ -16,6 +16,7 @@
 package com.android.quickstep.util;
 
 import static com.android.quickstep.views.RecentsView.ADJACENT_PAGE_HORIZONTAL_OFFSET;
+import static com.android.quickstep.views.RecentsView.RUNNING_TASK_ATTACH_ALPHA;
 
 import android.animation.Animator;
 import android.animation.ObjectAnimator;
@@ -33,8 +34,10 @@ public class RecentsAtomicAnimationFactory<CONTAINER extends Context & RecentsVi
 
     public static final int INDEX_RECENTS_FADE_ANIM = AtomicAnimationFactory.NEXT_INDEX + 0;
     public static final int INDEX_RECENTS_TRANSLATE_X_ANIM = AtomicAnimationFactory.NEXT_INDEX + 1;
+    public static final int INDEX_RECENTS_ATTACHED_ALPHA_ANIM =
+            AtomicAnimationFactory.NEXT_INDEX + 2;
 
-    private static final int MY_ANIM_COUNT = 2;
+    private static final int MY_ANIM_COUNT = 3;
 
     protected final CONTAINER mContainer;
 
@@ -50,6 +53,7 @@ public class RecentsAtomicAnimationFactory<CONTAINER extends Context & RecentsVi
                 ObjectAnimator alpha = ObjectAnimator.ofFloat(mContainer.getOverviewPanel(),
                         RecentsView.CONTENT_ALPHA, values);
                 return alpha;
+            case INDEX_RECENTS_ATTACHED_ALPHA_ANIM:
             case INDEX_RECENTS_TRANSLATE_X_ANIM: {
                 RecentsView rv = mContainer.getOverviewPanel();
                 return new SpringAnimationBuilder(mContainer)
@@ -57,7 +61,8 @@ public class RecentsAtomicAnimationFactory<CONTAINER extends Context & RecentsVi
                         .setDampingRatio(0.8f)
                         .setStiffness(250)
                         .setValues(values)
-                        .build(rv, ADJACENT_PAGE_HORIZONTAL_OFFSET);
+                        .build(rv, index == INDEX_RECENTS_ATTACHED_ALPHA_ANIM
+                                ? RUNNING_TASK_ATTACH_ALPHA : ADJACENT_PAGE_HORIZONTAL_OFFSET);
             }
             default:
                 return super.createStateElementAnimation(index, values);
diff --git a/quickstep/src/com/android/quickstep/views/RecentsView.java b/quickstep/src/com/android/quickstep/views/RecentsView.java
index f1ff0268cf..69a9690321 100644
--- a/quickstep/src/com/android/quickstep/views/RecentsView.java
+++ b/quickstep/src/com/android/quickstep/views/RecentsView.java
@@ -36,6 +36,7 @@ import static com.android.launcher3.AbstractFloatingView.TYPE_TASK_MENU;
 import static com.android.launcher3.AbstractFloatingView.getTopOpenViewWithType;
 import static com.android.launcher3.BaseActivity.STATE_HANDLER_INVISIBILITY_FLAGS;
 import static com.android.launcher3.Flags.enableAdditionalHomeAnimations;
+import static com.android.launcher3.Flags.enableDesktopTaskAlphaAnimation;
 import static com.android.launcher3.Flags.enableGridOnlyOverview;
 import static com.android.launcher3.Flags.enableLargeDesktopWindowingTile;
 import static com.android.launcher3.Flags.enableRefactorTaskThumbnail;
@@ -320,6 +321,27 @@ public abstract class RecentsView<
                 }
             };
 
+    public static final FloatProperty<RecentsView> RUNNING_TASK_ATTACH_ALPHA =
+            new FloatProperty<RecentsView>("runningTaskAttachAlpha") {
+                @Override
+                public void setValue(RecentsView recentsView, float v) {
+                    TaskView runningTask = recentsView.getRunningTaskView();
+                    if (runningTask == null) {
+                        return;
+                    }
+                    runningTask.setAttachAlpha(v);
+                }
+
+                @Override
+                public Float get(RecentsView recentsView) {
+                    TaskView runningTask = recentsView.getRunningTaskView();
+                    if (runningTask == null) {
+                        return null;
+                    }
+                    return runningTask.getAttachAlpha();
+                }
+            };
+
     public static final int SCROLL_VIBRATION_PRIMITIVE =
             Utilities.ATLEAST_S ? VibrationEffect.Composition.PRIMITIVE_LOW_TICK : -1;
     public static final float SCROLL_VIBRATION_PRIMITIVE_SCALE = 0.6f;
@@ -2737,10 +2759,17 @@ public abstract class RecentsView<
         showCurrentTask(mActiveGestureRunningTasks);
         setEnableFreeScroll(false);
         setEnableDrawingLiveTile(false);
-        setRunningTaskHidden(true);
+        setRunningTaskHidden(!shouldUpdateRunningTaskAlpha());
         setTaskIconScaledDown(true);
     }
 
+    /**
+     * Returns whether the running task's attach alpha should be updated during the attach animation
+     */
+    public boolean shouldUpdateRunningTaskAlpha() {
+        return enableDesktopTaskAlphaAnimation() && getRunningTaskView() instanceof DesktopTaskView;
+    }
+
     private boolean isGestureActive() {
         return mActiveGestureRunningTasks != null;
     }
@@ -3021,12 +3050,13 @@ public abstract class RecentsView<
     public void setRunningTaskHidden(boolean isHidden) {
         mRunningTaskTileHidden = isHidden;
         TaskView runningTask = getRunningTaskView();
-        if (runningTask != null) {
-            runningTask.setStableAlpha(isHidden ? 0 : mContentAlpha);
-            if (!isHidden) {
-                AccessibilityManagerCompat.sendCustomAccessibilityEvent(runningTask,
-                        AccessibilityEvent.TYPE_VIEW_FOCUSED, null);
-            }
+        if (runningTask == null) {
+            return;
+        }
+        runningTask.setStableAlpha(isHidden ? 0 : mContentAlpha);
+        if (!isHidden) {
+            AccessibilityManagerCompat.sendCustomAccessibilityEvent(
+                    runningTask, AccessibilityEvent.TYPE_VIEW_FOCUSED, null);
         }
     }
 
@@ -4701,8 +4731,11 @@ public abstract class RecentsView<
                     : showAsGrid
                             ? gridOffsetSize
                             : i < modalMidpoint ? modalLeftOffsetSize : modalRightOffsetSize;
-            float totalTranslationX = translation + modalTranslation;
             View child = getChildAt(i);
+            boolean skipTranslationOffset = enableDesktopTaskAlphaAnimation()
+                    && i == getRunningTaskIndex()
+                    && child instanceof DesktopTaskView;
+            float totalTranslationX = (skipTranslationOffset ? 0f : translation) + modalTranslation;
             FloatProperty translationPropertyX = child instanceof TaskView
                     ? ((TaskView) child).getPrimaryTaskOffsetTranslationProperty()
                     : getPagedOrientationHandler().getPrimaryViewTranslate();
diff --git a/quickstep/src/com/android/quickstep/views/TaskView.kt b/quickstep/src/com/android/quickstep/views/TaskView.kt
index e43d7b4fc0..b18f0b1769 100644
--- a/quickstep/src/com/android/quickstep/views/TaskView.kt
+++ b/quickstep/src/com/android/quickstep/views/TaskView.kt
@@ -65,6 +65,7 @@ import com.android.launcher3.util.DisplayController
 import com.android.launcher3.util.Executors
 import com.android.launcher3.util.MultiPropertyFactory
 import com.android.launcher3.util.MultiPropertyFactory.MULTI_PROPERTY_VALUE
+import com.android.launcher3.util.MultiValueAlpha
 import com.android.launcher3.util.RunnableList
 import com.android.launcher3.util.SafeCloseable
 import com.android.launcher3.util.SplitConfigurationOptions
@@ -391,11 +392,19 @@ constructor(
             applyTranslationX()
         }
 
-    protected var stableAlpha = 1f
+    private val taskViewAlpha = MultiValueAlpha(this, NUM_ALPHA_CHANNELS)
+
+    protected var stableAlpha
         set(value) {
-            field = value
-            alpha = stableAlpha
+            taskViewAlpha.get(ALPHA_INDEX_STABLE).value = value
         }
+        get() = taskViewAlpha.get(ALPHA_INDEX_STABLE).value
+
+    protected var attachAlpha
+        set(value) {
+            taskViewAlpha.get(ALPHA_INDEX_ATTACH).value = value
+        }
+        get() = taskViewAlpha.get(ALPHA_INDEX_ATTACH).value
 
     protected var shouldShowScreenshot = false
         get() = !isRunningTask || field
@@ -1584,7 +1593,7 @@ constructor(
         }
         dismissScale = 1f
         translationZ = 0f
-        alpha = stableAlpha
+        attachAlpha = 1f
         setIconScaleAndDim(1f)
         setColorTint(0f, 0)
     }
@@ -1661,6 +1670,11 @@ constructor(
         const val FOCUS_TRANSITION_INDEX_SCALE_AND_DIM = 1
         const val FOCUS_TRANSITION_INDEX_COUNT = 2
 
+        private const val ALPHA_INDEX_STABLE = 0
+        private const val ALPHA_INDEX_ATTACH = 1
+
+        private const val NUM_ALPHA_CHANNELS = 2
+
         /** The maximum amount that a task view can be scrimmed, dimmed or tinted. */
         const val MAX_PAGE_SCRIM_ALPHA = 0.4f
         const val SCALE_ICON_DURATION: Long = 120