From 259bea1652dc44cff0f06d0d865707c12096d4de Mon Sep 17 00:00:00 2001
From: bachinger <bachinger@google.com>
Date: Mon, 1 Jul 2019 19:13:03 +0100
Subject: [PATCH] MediaSessionConnector: Document how to provide metadata
 asynchronously

Issue: #6047
PiperOrigin-RevId: 255992898
---
 .../exoplayer2/ext/mediasession/MediaSessionConnector.java | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/extensions/mediasession/src/main/java/com/google/android/exoplayer2/ext/mediasession/MediaSessionConnector.java b/extensions/mediasession/src/main/java/com/google/android/exoplayer2/ext/mediasession/MediaSessionConnector.java
index eaebf8b4e1..3136e3cca9 100644
--- a/extensions/mediasession/src/main/java/com/google/android/exoplayer2/ext/mediasession/MediaSessionConnector.java
+++ b/extensions/mediasession/src/main/java/com/google/android/exoplayer2/ext/mediasession/MediaSessionConnector.java
@@ -378,6 +378,13 @@ public final class MediaSessionConnector {
     /**
      * Gets the {@link MediaMetadataCompat} to be published to the session.
      *
+     * <p>An app may need to load metadata resources like artwork bitmaps asynchronously. In such a
+     * case the app should return a {@link MediaMetadataCompat} object that does not contain these
+     * resources as a placeholder. The app should start an asynchronous operation to download the
+     * bitmap and put it into a cache. Finally, the app should call {@link
+     * #invalidateMediaSessionMetadata()}. This causes this callback to be called again and the app
+     * can now return a {@link MediaMetadataCompat} object with all the resources included.
+     *
      * @param player The player connected to the media session.
      * @return The {@link MediaMetadataCompat} to be published to the session.
      */