[Output Switcher] Fix recyclerview flickering

Bug: 219067810
Test: Verified on device
Change-Id: I7532a54a6b0fa945a4c87a9b8abb39f51d3a9aba

packages/SystemUI/src/com/android/systemui/media/dialog/MediaOutputAdapter.java

@@ -54,6 +54,7 @@ public class MediaOutputAdapter extends MediaOutputBaseAdapter {
             MediaOutputDialog mediaOutputDialog) {
         super(controller);
         mMediaOutputDialog = mediaOutputDialog;
+        setHasStableIds(true);
     }
 
     @Override
@@ -78,6 +79,20 @@ public class MediaOutputAdapter extends MediaOutputBaseAdapter {
         }
     }
 
+    @Override
+    public long getItemId(int position) {
+        final int size = mController.getMediaDevices().size();
+        if (position == size && mController.isZeroMode()) {
+            return -1;
+        } else if (position < size) {
+            return ((List<MediaDevice>) (mController.getMediaDevices()))
+                    .get(position).getId().hashCode();
+        } else if (DEBUG) {
+            Log.d(TAG, "Incorrect position for item id: " + position);
+        }
+        return position;
+    }
+
     @Override
     public int getItemCount() {
         if (mController.isZeroMode()) {