From d570d5ca3caeafd3b3779cc4ce7a04f07dc0bef7 Mon Sep 17 00:00:00 2001
From: Sungsoo <sungsoo@google.com>
Date: Thu, 18 Aug 2016 13:17:58 +0900
Subject: [PATCH] MediaBrowser: Make ItemCallback can take a null media item

When the implementation of MediaBrowserService returns null,
ItemCallback.onError was called, but the JavaDoc is saying that
ItemCallback.onItemLoaded can be called with a null result.

This CL makes ItemCallback.onItemLoaded be able to take a null result,
and ItemCallback.onError be called when the implementation doesn't override
the onLoadItem method or when the returned object is not MediaItem.

Bug: 27808084
Change-Id: I97cfd83786f8f857dc9551e5b0a358962f98e4a2
---
 media/java/android/media/browse/MediaBrowser.java |  2 +-
 .../service/media/MediaBrowserService.java        | 15 ++++++++++-----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/media/java/android/media/browse/MediaBrowser.java b/media/java/android/media/browse/MediaBrowser.java
index 4f2d9fbc899f0..957c2d6eb09f0 100644
--- a/media/java/android/media/browse/MediaBrowser.java
+++ b/media/java/android/media/browse/MediaBrowser.java
@@ -441,7 +441,7 @@ public final class MediaBrowser {
                     return;
                 }
                 Parcelable item = resultData.getParcelable(MediaBrowserService.KEY_MEDIA_ITEM);
-                if (!(item instanceof MediaItem)) {
+                if (item != null && !(item instanceof MediaItem)) {
                     cb.onError(mediaId);
                     return;
                 }
diff --git a/media/java/android/service/media/MediaBrowserService.java b/media/java/android/service/media/MediaBrowserService.java
index a811ad0e5a1f9..a19e347b4507c 100644
--- a/media/java/android/service/media/MediaBrowserService.java
+++ b/media/java/android/service/media/MediaBrowserService.java
@@ -91,10 +91,12 @@ public abstract class MediaBrowserService extends Service {
     public static final String KEY_MEDIA_ITEM = "media_item";
 
     private static final int RESULT_FLAG_OPTION_NOT_HANDLED = 0x00000001;
+    private static final int RESULT_FLAG_ON_LOAD_ITEM_NOT_IMPLEMENTED = 0x00000002;
 
     /** @hide */
     @Retention(RetentionPolicy.SOURCE)
-    @IntDef(flag=true, value = { RESULT_FLAG_OPTION_NOT_HANDLED })
+    @IntDef(flag=true, value = { RESULT_FLAG_OPTION_NOT_HANDLED,
+            RESULT_FLAG_ON_LOAD_ITEM_NOT_IMPLEMENTED })
     private @interface ResultFlags { }
 
     private final ArrayMap<IBinder, ConnectionRecord> mConnections = new ArrayMap<>();
@@ -433,11 +435,9 @@ public abstract class MediaBrowserService extends Service {
      * been loaded.
      * </p><p>
      * When the given {@code itemId} is invalid, implementations must call
-     * {@link Result#sendResult result.sendResult} with {@code null}, which will
-     * invoke {@link MediaBrowser.ItemCallback#onError}.
+     * {@link Result#sendResult result.sendResult} with {@code null}.
      * </p><p>
-     * The default implementation calls {@link Result#sendResult result.sendResult}
-     * with {@code null}.
+     * The default implementation will invoke {@link MediaBrowser.ItemCallback#onError}.
      * </p>
      *
      * @param itemId The id for the specific
@@ -445,6 +445,7 @@ public abstract class MediaBrowserService extends Service {
      * @param result The Result to send the item to.
      */
     public void onLoadItem(String itemId, Result<MediaBrowser.MediaItem> result) {
+        result.setFlags(RESULT_FLAG_ON_LOAD_ITEM_NOT_IMPLEMENTED);
         result.sendResult(null);
     }
 
@@ -703,6 +704,10 @@ public abstract class MediaBrowserService extends Service {
                 new Result<MediaBrowser.MediaItem>(itemId) {
             @Override
             void onResultSent(MediaBrowser.MediaItem item, @ResultFlags int flag) {
+                if ((flag & RESULT_FLAG_ON_LOAD_ITEM_NOT_IMPLEMENTED) != 0) {
+                    receiver.send(-1, null);
+                    return;
+                }
                 Bundle bundle = new Bundle();
                 bundle.putParcelable(KEY_MEDIA_ITEM, item);
                 receiver.send(0, bundle);