Gallery2: fix ConcurrentModificationException in MediaSet.java.

ConcurrentModificationException occured in mListeners' traversal operator
if another thread remove mListeners' item.

Add synchronized block to avoide ConcurrentModificationException.

Change-Id: I8816707a8340ffddf1900209b503029aa6683738
CRs-Fixed: 982803

1 files changed, 12 insertions, 4 deletions

diff --git a/src/com/android/gallery3d/data/MediaSet.java b/src/com/android/gallery3d/data/MediaSet.java
index b43874070..d0f0ec3c4 100644
--- a/src/com/android/gallery3d/data/MediaSet.java
+++ b/src/com/android/gallery3d/data/MediaSet.java
@@ -43,6 +43,8 @@ public abstract class MediaSet extends MediaObject {
     public static final int SYNC_RESULT_CANCELLED = 1;
     public static final int SYNC_RESULT_ERROR = 2;
 
+    private final Object mLock = new Object();
+
     /** Listener to be used with requestSync(SyncListener). */
     public static interface SyncListener {
         /**
@@ -180,17 +182,23 @@ public abstract class MediaSet extends MediaObject {
     // listener is automatically removed when there is no other reference to
     // the listener.
     public void addContentListener(ContentListener listener) {
-        mListeners.put(listener, null);
+        synchronized (mLock) {
+            mListeners.put(listener, null);
+        }
     }
 
     public void removeContentListener(ContentListener listener) {
-        mListeners.remove(listener);
+        synchronized (mLock) {
+            mListeners.remove(listener);
+        }
     }
 
     // This should be called by subclasses when the content is changed.
     public void notifyContentChanged() {
-        for (ContentListener listener : mListeners.keySet()) {
-            listener.onContentDirty();
+        synchronized (mLock) {
+            for (ContentListener listener : mListeners.keySet()) {
+                listener.onContentDirty();
+            }
         }
     }