From 103188a89c2e143d93a22a8e55f5ead46ee4b7ad Mon Sep 17 00:00:00 2001
From: Luca Zuccarini <acul@google.com>
Date: Thu, 15 Jun 2023 13:15:55 +0000
Subject: Avoid refreshing the media output dialog UI while dismissing.

refresh() currently performs several binder calls on the UI thread.
During launch of the dialog this happens before the animation, so while
there is a slight delay there are no frame drops. However when closing
the dialog the call happens after the animation has already started,
causing it to stutter significantly.

The proper fix would be to rearchitect this dialog so that state can be
loaded ahead of time and in the background, so the UI can start off
pre-populated and updates can come in whenever available. This would be
a risky change at this point in the U release cycle, and I'm not
familiar with the code enough to write it confidently, so for now simply
avoiding the updates if the dialog is dismissing removes the jank,
though it is only a band-aid.

Bug: 287191450
Flag: N/A
Test: see videos in the bug
Change-Id: If25937c86499b947a2f0d9971783f153f8e1a743
---
 .../media/dialog/MediaOutputBaseDialog.java        | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/packages/SystemUI/src/com/android/systemui/media/dialog/MediaOutputBaseDialog.java b/packages/SystemUI/src/com/android/systemui/media/dialog/MediaOutputBaseDialog.java
index 0a5b4b3066a0..7712690de195 100644
--- a/packages/SystemUI/src/com/android/systemui/media/dialog/MediaOutputBaseDialog.java
+++ b/packages/SystemUI/src/com/android/systemui/media/dialog/MediaOutputBaseDialog.java
@@ -105,6 +105,7 @@ public abstract class MediaOutputBaseDialog extends SystemUIDialog implements
     private WallpaperColors mWallpaperColors;
     private boolean mShouldLaunchLeBroadcastDialog;
     private boolean mIsLeBroadcastCallbackRegistered;
+    private boolean mDismissing;
 
     MediaOutputBaseAdapter mAdapter;
 
@@ -265,13 +266,22 @@ public abstract class MediaOutputBaseDialog extends SystemUIDialog implements
         mDevicesRecyclerView.setHasFixedSize(false);
         // Init bottom buttons
         mDoneButton.setOnClickListener(v -> dismiss());
-        mStopButton.setOnClickListener(v -> {
-            mMediaOutputController.releaseSession();
-            dismiss();
-        });
+        mStopButton.setOnClickListener(v -> onStopButtonClick());
         mAppButton.setOnClickListener(mMediaOutputController::tryToLaunchMediaApplication);
         mMediaMetadataSectionLayout.setOnClickListener(
                 mMediaOutputController::tryToLaunchMediaApplication);
+
+        mDismissing = false;
+    }
+
+    @Override
+    public void dismiss() {
+        // TODO(287191450): remove this once expensive binder calls are removed from refresh().
+        // Due to these binder calls on the UI thread, calling refresh() during dismissal causes
+        // significant frame drops for the dismissal animation. Since the dialog is going away
+        // anyway, we use this state to turn refresh() into a no-op.
+        mDismissing = true;
+        super.dismiss();
     }
 
     @Override
@@ -299,7 +309,9 @@ public abstract class MediaOutputBaseDialog extends SystemUIDialog implements
     }
 
     void refresh(boolean deviceSetChanged) {
-        if (mMediaOutputController.isRefreshing()) {
+        // TODO(287191450): remove binder calls in this method from the UI thread.
+        // If the dialog is going away or is already refreshing, do nothing.
+        if (mDismissing || mMediaOutputController.isRefreshing()) {
             return;
         }
         mMediaOutputController.setRefreshing(true);
-- 
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