Merge "Record latest back gesture occur on which task." into main
diff --git a/core/java/android/window/BackNavigationInfo.java b/core/java/android/window/BackNavigationInfo.java
index 59639d0..6cefc4d 100644
--- a/core/java/android/window/BackNavigationInfo.java
+++ b/core/java/android/window/BackNavigationInfo.java
@@ -16,6 +16,8 @@
 
 package android.window;
 
+import static android.app.ActivityTaskManager.INVALID_TASK_ID;
+
 import android.annotation.AnimRes;
 import android.annotation.ColorInt;
 import android.annotation.IntDef;
@@ -118,6 +120,7 @@
     private final Rect mTouchableRegion;
 
     private final boolean mAppProgressGenerationAllowed;
+    private final int mFocusedTaskId;
 
     /**
      * Create a new {@link BackNavigationInfo} instance.
@@ -135,7 +138,8 @@
             @Nullable CustomAnimationInfo customAnimationInfo,
             int letterboxColor,
             @Nullable Rect touchableRegion,
-            boolean appProgressGenerationAllowed) {
+            boolean appProgressGenerationAllowed,
+            int focusedTaskId) {
         mType = type;
         mOnBackNavigationDone = onBackNavigationDone;
         mOnBackInvokedCallback = onBackInvokedCallback;
@@ -145,6 +149,7 @@
         mLetterboxColor = letterboxColor;
         mTouchableRegion = new Rect(touchableRegion);
         mAppProgressGenerationAllowed = appProgressGenerationAllowed;
+        mFocusedTaskId = focusedTaskId;
     }
 
     private BackNavigationInfo(@NonNull Parcel in) {
@@ -157,6 +162,7 @@
         mLetterboxColor = in.readInt();
         mTouchableRegion = in.readTypedObject(Rect.CREATOR);
         mAppProgressGenerationAllowed = in.readBoolean();
+        mFocusedTaskId = in.readInt();
     }
 
     /** @hide */
@@ -171,6 +177,7 @@
         dest.writeInt(mLetterboxColor);
         dest.writeTypedObject(mTouchableRegion, flags);
         dest.writeBoolean(mAppProgressGenerationAllowed);
+        dest.writeInt(mFocusedTaskId);
     }
 
     /**
@@ -238,6 +245,14 @@
     }
 
     /**
+     * @return The focused task id when back gesture start.
+     * @hide
+     */
+    public int getFocusedTaskId() {
+        return mFocusedTaskId;
+    }
+
+    /**
      * Callback to be called when the back preview is finished in order to notify the server that
      * it can clean up the resources created for the animation.
      * @hide
@@ -435,6 +450,7 @@
         private int mLetterboxColor = Color.TRANSPARENT;
         private Rect mTouchableRegion;
         private boolean mAppProgressGenerationAllowed;
+        private int mFocusedTaskId = INVALID_TASK_ID;
 
         /**
          * @see BackNavigationInfo#getType()
@@ -527,6 +543,14 @@
         }
 
         /**
+         * @param focusedTaskId The current focused taskId when back gesture start.
+         */
+        public Builder setFocusedTaskId(int focusedTaskId) {
+            mFocusedTaskId = focusedTaskId;
+            return this;
+        }
+
+        /**
          * Builds and returns an instance of {@link BackNavigationInfo}
          */
         public BackNavigationInfo build() {
@@ -537,7 +561,8 @@
                     mCustomAnimationInfo,
                     mLetterboxColor,
                     mTouchableRegion,
-                    mAppProgressGenerationAllowed);
+                    mAppProgressGenerationAllowed,
+                    mFocusedTaskId);
         }
     }
 }
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java b/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java
index 19b51f1..fafb69c 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java
@@ -164,6 +164,9 @@
      */
     private BackTouchTracker mQueuedTracker = new BackTouchTracker();
 
+    private final FocusTaskTrackerObserver mFocusTaskTrackerObserver =
+            new FocusTaskTrackerObserver();
+
     private final Runnable mAnimationTimeoutRunnable = () -> {
         ProtoLog.w(WM_SHELL_BACK_PREVIEW, "Animation didn't finish in %d ms. Resetting...",
                 MAX_ANIMATION_DURATION);
@@ -268,6 +271,7 @@
         mBackTransitionHandler = new BackTransitionHandler();
         mTransitions.addHandler(mBackTransitionHandler);
         mHandler = handler;
+        mTransitions.registerObserver(mFocusTaskTrackerObserver);
         updateTouchableArea();
     }
 
@@ -729,6 +733,13 @@
     }
 
     /**
+     * @return Latest task id which back gesture has occurred on it.
+     */
+    public int getLatestTriggerBackTask() {
+        return mFocusTaskTrackerObserver.mFocusedTaskId;
+    }
+
+    /**
      * Sets to true when the back gesture has passed the triggering threshold, false otherwise.
      */
     public void setTriggerBack(boolean triggerBack) {
@@ -792,6 +803,11 @@
         boolean triggerBack = activeTouchTracker.getTriggerBack();
         ProtoLog.d(WM_SHELL_BACK_PREVIEW, "onGestureFinished() mTriggerBack == %s", triggerBack);
 
+        if (triggerBack) {
+            mFocusTaskTrackerObserver.update(mBackNavigationInfo != null
+                            ? mBackNavigationInfo.getFocusedTaskId()
+                            : INVALID_TASK_ID);
+        }
         // Reset gesture states.
         mThresholdCrossed = false;
         mPointersPilfered = false;
@@ -1645,4 +1661,48 @@
     private static boolean canBeTransitionTarget(TransitionInfo.Change change) {
         return findComponentName(change) != null || findTaskId(change) != INVALID_TASK_ID;
     }
+
+    // Record the latest back gesture happen on which task.
+    static class FocusTaskTrackerObserver implements Transitions.TransitionObserver {
+        int mFocusedTaskId = INVALID_TASK_ID;
+        IBinder mMonitorBinder;
+
+        void update(int focusedTaskId) {
+            mFocusedTaskId = focusedTaskId;
+        }
+
+        @Override
+        public void onTransitionReady(@NonNull IBinder transition, @NonNull TransitionInfo info,
+                @NonNull SurfaceControl.Transaction startTransaction,
+                @NonNull SurfaceControl.Transaction finishTransaction) {
+            if (mFocusedTaskId == INVALID_TASK_ID) {
+                return;
+            }
+            for (int i = info.getChanges().size() - 1; i >= 0; --i) {
+                final TransitionInfo.Change c = info.getChanges().get(i);
+                if (c.getTaskInfo() != null && c.getTaskInfo().taskId == mFocusedTaskId) {
+                    mMonitorBinder = transition;
+                    break;
+                }
+            }
+            // Transition happen but the task isn't involved, reset.
+            if (mMonitorBinder == null) {
+                mFocusedTaskId = INVALID_TASK_ID;
+            }
+        }
+
+        @Override
+        public void onTransitionMerged(@NonNull IBinder merged, @NonNull IBinder playing) {
+            if (mMonitorBinder == merged) {
+                mMonitorBinder = playing;
+            }
+        }
+
+        @Override
+        public void onTransitionFinished(@NonNull IBinder transition, boolean aborted) {
+            if (mMonitorBinder == transition) {
+                mFocusedTaskId = INVALID_TASK_ID;
+            }
+        }
+    }
 }
diff --git a/services/core/java/com/android/server/wm/BackNavigationController.java b/services/core/java/com/android/server/wm/BackNavigationController.java
index 70f9ebb..ccd5996 100644
--- a/services/core/java/com/android/server/wm/BackNavigationController.java
+++ b/services/core/java/com/android/server/wm/BackNavigationController.java
@@ -201,6 +201,9 @@
             infoBuilder.setTouchableRegion(window.getFrame());
             infoBuilder.setAppProgressAllowed((window.getAttrs().privateFlags
                     & PRIVATE_FLAG_APP_PROGRESS_GENERATION_ALLOWED) != 0);
+            if (currentTask != null) {
+                infoBuilder.setFocusedTaskId(currentTask.mTaskId);
+            }
             mNavigationMonitor.startMonitor(window, navigationObserver);
 
             ProtoLog.d(WM_DEBUG_BACK_PREVIEW, "startBackNavigation currentTask=%s, "