From 980c089d2f72e3369efb88cd793f071e75a4b0b5 Mon Sep 17 00:00:00 2001
From: Sunny Goyal <sunnygoyal@google.com>
Date: Tue, 8 Dec 2020 19:19:56 -0800
Subject: [PATCH] [DO NOT MERGE] Keeping Launcher in overview UI if activity is
 restarting due to UI mode changes

Test: Verified Launcher behavior locally
Bug: 148988542
Change-Id: Id83e5e0892666af1420e8f8c711b83f1ea355188
(cherry picked from commit 6c0c61acd8e81be312e1edda5f9a3c85a0718746)
---
 src/com/android/launcher3/Launcher.java        | 18 +++++++++++++++++-
 .../statemanager/StatefulActivity.java         |  4 +++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index e1f2b325f3..ae89deda47 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -18,6 +18,7 @@ package com.android.launcher3;
 
 import static android.content.pm.ActivityInfo.CONFIG_ORIENTATION;
 import static android.content.pm.ActivityInfo.CONFIG_SCREEN_SIZE;
+import static android.content.pm.ActivityInfo.CONFIG_UI_MODE;
 import static android.view.accessibility.AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED;
 
 import static com.android.launcher3.AbstractFloatingView.TYPE_ALL;
@@ -1103,7 +1104,11 @@ public class Launcher extends StatefulActivity<LauncherState> implements Launche
         int stateOrdinal = savedState.getInt(RUNTIME_STATE, NORMAL.ordinal);
         LauncherState[] stateValues = LauncherState.values();
         LauncherState state = stateValues[stateOrdinal];
-        if (!state.shouldDisableRestore()) {
+
+        NonConfigInstance lastInstance = (NonConfigInstance) getLastNonConfigurationInstance();
+        boolean forceRestore = lastInstance != null
+                && (lastInstance.config.diff(mOldConfig) & CONFIG_UI_MODE) != 0;
+        if (forceRestore || !state.shouldDisableRestore()) {
             mStateManager.goToState(state, false /* animated */);
         }
 
@@ -1343,6 +1348,13 @@ public class Launcher extends StatefulActivity<LauncherState> implements Launche
         closeContextMenu();
     }
 
+    @Override
+    public Object onRetainNonConfigurationInstance() {
+        NonConfigInstance instance = new NonConfigInstance();
+        instance.config = new Configuration(mOldConfig);
+        return instance;
+    }
+
     public AllAppsTransitionController getAllAppsController() {
         return mAllAppsController;
     }
@@ -2745,4 +2757,8 @@ public class Launcher extends StatefulActivity<LauncherState> implements Launche
 
         void onLauncherResume();
     }
+
+    private static class NonConfigInstance {
+        public Configuration config;
+    }
 }
diff --git a/src/com/android/launcher3/statemanager/StatefulActivity.java b/src/com/android/launcher3/statemanager/StatefulActivity.java
index dbe5f42e31..601e117f1c 100644
--- a/src/com/android/launcher3/statemanager/StatefulActivity.java
+++ b/src/com/android/launcher3/statemanager/StatefulActivity.java
@@ -121,7 +121,9 @@ public abstract class StatefulActivity<STATE_TYPE extends BaseState<STATE_TYPE>>
         final int origDragLayerChildCount = dragLayer.getChildCount();
         super.onStop();
 
-        getStateManager().moveToRestState();
+        if (!isChangingConfigurations()) {
+            getStateManager().moveToRestState();
+        }
 
         // Workaround for b/78520668, explicitly trim memory once UI is hidden
         onTrimMemory(TRIM_MEMORY_UI_HIDDEN);