commit 4dd3fb3e2c2b0d3dd7cb18f9e7e40a7b9dee8692
author Jean-Michel Trivi <jmtrivi@google.com> Tue Nov 20 17:06:51 2012 -0800
committer Jean-Michel Trivi <jmtrivi@google.com> Tue Nov 20 17:59:34 2012 -0800
tree 22df76b15a056eca93363e87cb72334696756df4
parent 02053d1cce52f11ef1bc3b562279940208f9c54e

Fix audio focus evaluation order for display update

Change 1f9196a8e5de9b004e61afabc70b18caf7cf9c7e introduced
 an issue when trying to ignore audio focus entries in the
 stack that don't use the music stream, or are for transient
 audio focus gain, for remote control display updates.
The bug was that the audio focus stack traversal was not
 starting from the top, as it should. It was using
 the iterator order, which, in the case of a stack, starts
 with the bottom-most entry.
The fix consists in traversing the stack from the top, i.e.
 from the last element of the vector used to hold the stack
 entries.

Bug 7311023

Change-Id: I0c1900dbf98599a621a420ab55531a3eee838fe5

media/java/android/media/AudioService.java

diff --git a/media/java/android/media/AudioService.java b/media/java/android/media/AudioService.java
index 22f699f..56abed4 100644
--- a/media/java/android/media/AudioService.java
+++ b/media/java/android/media/AudioService.java
@@ -5088,18 +5088,23 @@
         // top of the stack for the media button event receivers : simply using the top of the
         // stack would make the entry disappear from the RemoteControlDisplay in conditions such as
         // notifications playing during music playback.
-        // crawl the AudioFocus stack until an entry is found with the following characteristics:
+        // Crawl the AudioFocus stack from the top until an entry is found with the following
+        // characteristics:
         // - focus gain on STREAM_MUSIC stream
         // - non-transient focus gain on a stream other than music
         FocusStackEntry af = null;
-        Iterator<FocusStackEntry> stackIterator = mFocusStack.iterator();
-        while(stackIterator.hasNext()) {
-            FocusStackEntry fse = (FocusStackEntry)stackIterator.next();
-            if ((fse.mStreamType == AudioManager.STREAM_MUSIC)
-                    || (fse.mFocusChangeType == AudioManager.AUDIOFOCUS_GAIN)) {
-                af = fse;
-                break;
+        try {
+            for (int index = mFocusStack.size()-1; index >= 0; index--) {
+                FocusStackEntry fse = mFocusStack.elementAt(index);
+                if ((fse.mStreamType == AudioManager.STREAM_MUSIC)
+                        || (fse.mFocusChangeType == AudioManager.AUDIOFOCUS_GAIN)) {
+                    af = fse;
+                    break;
+                }
             }
+        } catch (ArrayIndexOutOfBoundsException e) {
+            Log.e(TAG, "Wrong index accessing audio focus stack when updating RCD: " + e);
+            af = null;
         }
         if (af == null) {
             clearRemoteControlDisplay_syncAfRcs();
@@ -5120,6 +5125,7 @@
             clearRemoteControlDisplay_syncAfRcs();
             return;
         }
+
         // refresh conditions were verified: update the remote controls
         // ok to call: synchronized mAudioFocusLock then on mRCStack, mRCStack is not empty
         updateRemoteControlDisplay_syncAfRcs(infoChangedFlags);