Correct recycling to take setViewId into account.

Views shouldn't be recycled if the view id is changed as the identity
of the view is then altered.

Second pass: this has been further tested by adding/removing AppWidgets
on a test phone.

Bug: 181985606
Test: atest CtsWidgetTestCases:RemoteViewsTest
Test: atest CtsWidgetTestCases:RemoteViewsRecyclingTest
Test: atest CtsInputMethodTestCases:android.view.inputmethod.cts.InputConnectionBlockingMethodTest
Change-Id: I8924c02f7f0223458f556a07a3dfdc96b4ce612e

core/java/android/appwidget/AppWidgetHostView.java

@@ -520,9 +520,7 @@ public class AppWidgetHostView extends FrameLayout {
                 return;
             }
             int layoutId = rvToApply.getLayoutId();
-            // If our stale view has been prepared to match active, and the new
-            // layout matches, try recycling it
-            if (content == null && layoutId == mLayoutId) {
+            if (rvToApply.canRecycleView(mView)) {
                 try {
                     rvToApply.reapply(mContext, mView, mInteractionHandler, mCurrentSize,
                             mColorResources);

core/java/android/widget/RemoteViews.java

@@ -2196,7 +2196,7 @@ public class RemoteViews implements Parcelable, Filter {
                 int recycledViewIndex = findViewIndexToRecycle(target, rvToApply);
                 if (recycledViewIndex >= 0) {
                     View child = target.getChildAt(recycledViewIndex);
-                    if (getViewLayoutId(child) == rvToApply.getLayoutId()) {
+                    if (rvToApply.canRecycleView(child)) {
                         if (nextChild < recycledViewIndex) {
                             target.removeViews(nextChild, recycledViewIndex - nextChild);
                         }
@@ -2254,7 +2254,7 @@ public class RemoteViews implements Parcelable, Filter {
                     // application are placed before.
                     ViewTree recycled = target.mChildren.get(recycledViewIndex);
                     // We can only recycle the view if the layout id is the same.
-                    if (getViewLayoutId(recycled.mRoot) == rvToApply.getLayoutId()) {
+                    if (rvToApply.canRecycleView(recycled.mRoot)) {
                         if (recycledViewIndex > nextChild) {
                             target.removeChildren(nextChild, recycledViewIndex - nextChild);
                         }
@@ -3726,7 +3726,8 @@ public class RemoteViews implements Parcelable, Filter {
      *
      * The {@code stableId} will be used to identify a potential view to recycled when the remote
      * view is inflated. Views can be re-used if inserted in the same order, potentially with
-     * some views appearing / disappearing.
+     * some views appearing / disappearing. To be recycled the view must not change the layout
+     * used to inflate it or its view id (see {@link RemoteViews#setViewId}).
      *
      * Note: if a view is re-used, all the actions will be re-applied on it. However, its properties
      * are not reset, so what was applied in previous round will have an effect. As a view may be
@@ -5116,6 +5117,7 @@ public class RemoteViews implements Parcelable, Filter {
         View v = inflater.inflate(rv.getLayoutId(), parent, false);
         if (mViewId != View.NO_ID) {
             v.setId(mViewId);
+            v.setTagInternal(R.id.remote_views_override_id, mViewId);
         }
         v.setTagInternal(R.id.widget_frame, rv.getLayoutId());
         return v;
@@ -5335,6 +5337,24 @@ public class RemoteViews implements Parcelable, Filter {
         reapply(context, v, handler, size, colorResources, true);
     }
 
+    /** @hide */
+    public boolean canRecycleView(@Nullable View v) {
+        if (v == null) {
+            return false;
+        }
+        Integer previousLayoutId = (Integer) v.getTag(R.id.widget_frame);
+        if (previousLayoutId == null) {
+            return false;
+        }
+        Integer overrideIdTag = (Integer) v.getTag(R.id.remote_views_override_id);
+        int overrideId = overrideIdTag == null ? View.NO_ID : overrideIdTag;
+        // If mViewId is View.NO_ID, we only recycle if overrideId is also View.NO_ID.
+        // Otherwise, it might be that, on a previous iteration, the view's ID was set to
+        // something else, and it should now be reset to the ID defined in the XML layout file,
+        // whatever it is.
+        return previousLayoutId == getLayoutId() && mViewId == overrideId;
+    }
+
     // Note: topLevel should be true only for calls on the topLevel RemoteViews, internal calls
     // should set it to false.
     private void reapply(Context context, View v, InteractionHandler handler, SizeF size,
@@ -5347,7 +5367,7 @@ public class RemoteViews implements Parcelable, Filter {
         // (orientation or size), we throw an exception, since the layouts may be completely
         // unrelated.
         if (hasMultipleLayouts()) {
-            if ((Integer) v.getTag(R.id.widget_frame) != rvToApply.getLayoutId()) {
+            if (!rvToApply.canRecycleView(v)) {
                 throw new RuntimeException("Attempting to re-apply RemoteViews to a view that" +
                         " that does not share the same root layout id.");
             }

core/res/res/values/ids.xml

@@ -252,5 +252,8 @@
   <item type="id" name="remote_views_next_child" />
 
   <!-- View tag associating a view with its stable id for potential recycling. -->
-  <item type="id" name = "remote_views_stable_id" />
+  <item type="id" name="remote_views_stable_id" />
+
+  <!-- View tag associating a view with its overridden id, to ensure valid recycling only. -->
+  <item type="id" name="remote_views_override_id" />
 </resources>

core/res/res/values/symbols.xml

@@ -4321,8 +4321,11 @@
   <java-symbol type="bool" name="config_cecRcProfileSourceMediaContextSensitiveMenuNotHandled_allowed" />
   <java-symbol type="bool" name="config_cecRcProfileSourceMediaContextSensitiveMenuNotHandled_default" />
 
+  <!-- Ids for RemoteViews -->
   <java-symbol type="id" name="remote_views_next_child" />
   <java-symbol type="id" name="remote_views_stable_id" />
+  <java-symbol type="id" name="remote_views_override_id" />
+
   <!-- View and control prompt -->
   <java-symbol type="drawable" name="ic_accessibility_24dp" />
   <java-symbol type="string" name="view_and_control_notification_title" />