Merge "Cache and reuses LauncherAppWidgetHostView when launcher resumes" into tm-qpr-dev
diff --git a/src/com/android/launcher3/config/FeatureFlags.java b/src/com/android/launcher3/config/FeatureFlags.java
index 38b5c65..da5c4c2 100644
--- a/src/com/android/launcher3/config/FeatureFlags.java
+++ b/src/com/android/launcher3/config/FeatureFlags.java
@@ -277,6 +277,10 @@
             "ENABLE_DISMISS_PREDICTION_UNDO", false,
             "Show an 'Undo' snackbar when users dismiss a predicted hotseat item");
 
+    public static final BooleanFlag ENABLE_CACHED_WIDGET = getDebugFlag(
+            "ENABLE_CACHED_WIDGET", true,
+            "Show previously cached widgets as opposed to deferred widget where available");
+
     public static void initialize(Context context) {
         synchronized (sDebugFlags) {
             for (DebugFlag flag : sDebugFlags) {
diff --git a/src/com/android/launcher3/widget/LauncherAppWidgetHost.java b/src/com/android/launcher3/widget/LauncherAppWidgetHost.java
index fe83f3f..98a960c 100644
--- a/src/com/android/launcher3/widget/LauncherAppWidgetHost.java
+++ b/src/com/android/launcher3/widget/LauncherAppWidgetHost.java
@@ -28,6 +28,7 @@
 import android.os.Bundle;
 import android.os.Handler;
 import android.util.SparseArray;
+import android.widget.RemoteViews;
 import android.widget.Toast;
 
 import androidx.annotation.Nullable;
@@ -37,6 +38,7 @@
 import com.android.launcher3.LauncherAppState;
 import com.android.launcher3.R;
 import com.android.launcher3.Utilities;
+import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.model.WidgetsModel;
 import com.android.launcher3.model.data.ItemInfo;
 import com.android.launcher3.testing.TestLogging;
@@ -70,13 +72,14 @@
     private final ArrayList<ProviderChangedListener> mProviderChangeListeners = new ArrayList<>();
     private final SparseArray<LauncherAppWidgetHostView> mViews = new SparseArray<>();
     private final SparseArray<PendingAppWidgetHostView> mPendingViews = new SparseArray<>();
+    private final SparseArray<LauncherAppWidgetHostView> mDeferredViews = new SparseArray<>();
+    private final SparseArray<RemoteViews> mCachedRemoteViews = new SparseArray<>();
 
     private final Context mContext;
     private int mFlags = FLAG_STATE_IS_NORMAL;
 
     private IntConsumer mAppWidgetRemovedCallback = null;
 
-
     public LauncherAppWidgetHost(Context context) {
         this(context, null);
     }
@@ -95,6 +98,11 @@
         if (mPendingViews.get(appWidgetId) != null) {
             view = mPendingViews.get(appWidgetId);
             mPendingViews.remove(appWidgetId);
+        } else if (mDeferredViews.get(appWidgetId) != null) {
+            // In case the widget view is deferred, we will simply return the deferred view as
+            // opposed to instantiate a new instance of LauncherAppWidgetHostView since launcher
+            // already added the former to the workspace.
+            view = mDeferredViews.get(appWidgetId);
         } else {
             view = new LauncherAppWidgetHostView(context);
         }
@@ -120,12 +128,25 @@
             // widgets upon bind anyway. See issue 14255011 for more context.
         }
 
-        // We go in reverse order and inflate any deferred widget
+        // We go in reverse order and inflate any deferred or cached widget
         for (int i = mViews.size() - 1; i >= 0; i--) {
             LauncherAppWidgetHostView view = mViews.valueAt(i);
             if (view instanceof DeferredAppWidgetHostView) {
                 view.reInflate();
             }
+            if (FeatureFlags.ENABLE_CACHED_WIDGET.get()) {
+                final int appWidgetId = mViews.keyAt(i);
+                if (view == mDeferredViews.get(appWidgetId)) {
+                    // If the widget view was deferred, we'll need to call super.createView here
+                    // to make the binder call to system process to fetch cumulative updates to this
+                    // widget, as well as setting up this view for future updates.
+                    super.createView(view.mLauncher, appWidgetId, view.getAppWidgetInfo());
+                    // At this point #onCreateView should have been called, which in turn returned
+                    // the deferred view. There's no reason to keep the reference anymore, so we
+                    // removed it here.
+                    mDeferredViews.remove(appWidgetId);
+                }
+            }
         }
     }
 
@@ -221,10 +242,28 @@
             CustomWidgetManager.INSTANCE.get(context).onViewCreated(lahv);
             return lahv;
         } else if ((mFlags & FLAG_LISTENING) == 0) {
-            DeferredAppWidgetHostView view = new DeferredAppWidgetHostView(context);
-            view.setAppWidget(appWidgetId, appWidget);
-            mViews.put(appWidgetId, view);
-            return view;
+            // Since the launcher hasn't started listening to widget updates, we can't simply call
+            // super.createView here because the later will make a binder call to retrieve
+            // RemoteViews from system process.
+            // TODO: have launcher always listens to widget updates in background so that this
+            //  check can be removed altogether.
+            if (FeatureFlags.ENABLE_CACHED_WIDGET.get()
+                    && mCachedRemoteViews.get(appWidgetId) != null) {
+                // We've found RemoteViews from cache for this widget, so we will instantiate a
+                // widget host view and populate it with the cached RemoteViews.
+                final LauncherAppWidgetHostView view = new LauncherAppWidgetHostView(context);
+                view.setAppWidget(appWidgetId, appWidget);
+                view.updateAppWidget(mCachedRemoteViews.get(appWidgetId));
+                mDeferredViews.put(appWidgetId, view);
+                mViews.put(appWidgetId, view);
+                return view;
+            } else {
+                // When cache misses, a placeholder for the widget will be returned instead.
+                DeferredAppWidgetHostView view = new DeferredAppWidgetHostView(context);
+                view.setAppWidget(appWidgetId, appWidget);
+                mViews.put(appWidgetId, view);
+                return view;
+            }
         } else {
             try {
                 return super.createView(context, appWidgetId, appWidget);
@@ -281,6 +320,16 @@
     @Override
     public void clearViews() {
         super.clearViews();
+        if (FeatureFlags.ENABLE_CACHED_WIDGET.get()) {
+            // First, we clear any previously cached content from existing widgets
+            mCachedRemoteViews.clear();
+            // Then we proceed to cache the content from the widgets
+            for (int i = 0; i < mViews.size(); i++) {
+                final int appWidgetId = mViews.keyAt(i);
+                final LauncherAppWidgetHostView view = mViews.get(appWidgetId);
+                mCachedRemoteViews.put(appWidgetId, view.mLastRemoteViews);
+            }
+        }
         mViews.clear();
     }
 
diff --git a/src/com/android/launcher3/widget/LauncherAppWidgetHostView.java b/src/com/android/launcher3/widget/LauncherAppWidgetHostView.java
index 0865152..fc1e880 100644
--- a/src/com/android/launcher3/widget/LauncherAppWidgetHostView.java
+++ b/src/com/android/launcher3/widget/LauncherAppWidgetHostView.java
@@ -43,6 +43,7 @@
 import com.android.launcher3.Launcher;
 import com.android.launcher3.R;
 import com.android.launcher3.Utilities;
+import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.dragndrop.DragLayer;
 import com.android.launcher3.model.data.ItemInfo;
 import com.android.launcher3.model.data.LauncherAppWidgetInfo;
@@ -85,7 +86,7 @@
     private Runnable mAutoAdvanceRunnable;
 
     private long mDeferUpdatesUntilMillis = 0;
-    private RemoteViews mDeferredRemoteViews;
+    RemoteViews mLastRemoteViews;
     private boolean mHasDeferredColorChange = false;
     private @Nullable SparseIntArray mDeferredColorChange = null;
 
@@ -150,11 +151,18 @@
                     TRACE_METHOD_NAME + getAppWidgetInfo().provider, getAppWidgetId());
             mTrackingWidgetUpdate = false;
         }
-        if (isDeferringUpdates()) {
-            mDeferredRemoteViews = remoteViews;
-            return;
+        if (FeatureFlags.ENABLE_CACHED_WIDGET.get()) {
+            mLastRemoteViews = remoteViews;
+            if (isDeferringUpdates()) {
+                return;
+            }
+        } else {
+            if (isDeferringUpdates()) {
+                mLastRemoteViews = remoteViews;
+                return;
+            }
+            mLastRemoteViews = null;
         }
-        mDeferredRemoteViews = null;
 
         super.updateAppWidget(remoteViews);
 
@@ -218,8 +226,7 @@
         SparseIntArray deferredColors;
         boolean hasDeferredColors;
         mDeferUpdatesUntilMillis = 0;
-        remoteViews = mDeferredRemoteViews;
-        mDeferredRemoteViews = null;
+        remoteViews = mLastRemoteViews;
         deferredColors = mDeferredColorChange;
         hasDeferredColors = mHasDeferredColorChange;
         mDeferredColorChange = null;