From 25f82728105f9d9b4ddefbb341bcc202a23be701 Mon Sep 17 00:00:00 2001
From: Jerry Chang <chenghsiuchang@google.com>
Date: Wed, 13 Jan 2021 20:21:34 +0800
Subject: [PATCH] Reparent remaining tasks to matching launch root when display
 removed

When display removed, reparent remaining tasks to the top of matching
launch root instead of having special logic for reparenting task to
split root. And update focus to the new root task if the last reparented
task has been reparented to another root task.

Bug: 177190100
Test: Passed existing tests
Change-Id: I5c0f4c52a01221bb89001ebc0ca25319ae41b8dd
---
 .../android/server/wm/TaskDisplayArea.java    | 29 ++++++++++---------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/services/core/java/com/android/server/wm/TaskDisplayArea.java b/services/core/java/com/android/server/wm/TaskDisplayArea.java
index 832fc688d6eb4..db26e05e1925c 100644
--- a/services/core/java/com/android/server/wm/TaskDisplayArea.java
+++ b/services/core/java/com/android/server/wm/TaskDisplayArea.java
@@ -19,7 +19,6 @@ package com.android.server.wm;
 import static android.app.ActivityTaskManager.INVALID_TASK_ID;
 import static android.app.WindowConfiguration.ACTIVITY_TYPE_HOME;
 import static android.app.WindowConfiguration.ACTIVITY_TYPE_RECENTS;
-import static android.app.WindowConfiguration.ACTIVITY_TYPE_STANDARD;
 import static android.app.WindowConfiguration.ACTIVITY_TYPE_UNDEFINED;
 import static android.app.WindowConfiguration.WINDOWING_MODE_FREEFORM;
 import static android.app.WindowConfiguration.WINDOWING_MODE_FULLSCREEN;
@@ -1848,9 +1847,6 @@ final class TaskDisplayArea extends DisplayArea<WindowContainer> {
         // Keep the order from bottom to top.
         int numRootTasks = mChildren.size();
 
-        final boolean splitScreenActivated = toDisplayArea.isSplitScreenModeActivated();
-        final Task splitScreenRoot = splitScreenActivated ? toDisplayArea
-                .getTopRootTaskInWindowingMode(WINDOWING_MODE_SPLIT_SCREEN_SECONDARY) : null;
         for (int i = 0; i < numRootTasks; i++) {
             final WindowContainer child = mChildren.get(i);
             if (child.asTaskDisplayArea() != null) {
@@ -1866,10 +1862,12 @@ final class TaskDisplayArea extends DisplayArea<WindowContainer> {
                     || task.mCreatedByOrganizer) {
                 task.finishAllActivitiesImmediately();
             } else {
-                // Reparent the root task to the root task of secondary-split-screen or display
-                // area.
-                task.reparent(task.supportsSplitScreenWindowingMode() && splitScreenRoot != null
-                        ? splitScreenRoot : toDisplayArea, POSITION_TOP);
+                // Reparent task to corresponding launch root or display area.
+                final WindowContainer launchRoot = task.supportsSplitScreenWindowingMode()
+                        ? toDisplayArea.getLaunchRootTask(
+                                task.getWindowingMode(), task.getActivityType())
+                        : null;
+                task.reparent(launchRoot == null ? toDisplayArea : launchRoot, POSITION_TOP);
 
                 // Set the windowing mode to undefined by default to let the root task inherited the
                 // windowing mode.
@@ -1881,14 +1879,19 @@ final class TaskDisplayArea extends DisplayArea<WindowContainer> {
             i -= numRootTasks - mChildren.size();
             numRootTasks = mChildren.size();
         }
-        if (lastReparentedRootTask != null && splitScreenActivated) {
-            if (!lastReparentedRootTask.supportsSplitScreenWindowingMode()) {
+
+        if (lastReparentedRootTask != null) {
+            if (toDisplayArea.isSplitScreenModeActivated()
+                    && !lastReparentedRootTask.supportsSplitScreenWindowingMode()) {
+                // Dismiss split screen if the last reparented root task doesn't support split mode.
                 mAtmService.getTaskChangeNotificationController()
                         .notifyActivityDismissingDockedStack();
                 toDisplayArea.onSplitScreenModeDismissed(lastReparentedRootTask);
-            } else if (splitScreenRoot != null) {
-                // update focus
-                splitScreenRoot.moveToFront("display-removed");
+            } else if (!lastReparentedRootTask.isRootTask()) {
+                // Update focus when the last reparented root task is not a root task anymore.
+                // (For example, if it has been reparented to a split screen root task, move the
+                // focus to the split root task)
+                lastReparentedRootTask.getRootTask().moveToFront("display-removed");
             }
         }