1 files changed, 27 insertions, 0 deletions
diff --git a/extensions/baseAdapters/src/main/java/android/databinding/adapters/ListenerUtil.java b/extensions/baseAdapters/src/main/java/android/databinding/adapters/ListenerUtil.java
index 67ae1727..6869cdba 100644
--- a/extensions/baseAdapters/src/main/java/android/databinding/adapters/ListenerUtil.java
+++ b/extensions/baseAdapters/src/main/java/android/databinding/adapters/ListenerUtil.java
@@ -79,4 +79,31 @@ public class ListenerUtil {
         }
     }
 
+    /**
+     * Returns the previous value for a listener if one was stored previously with
+     * {@link #trackListener(View, Object, int)}
+     * @param view The View to check for a listener previously stored with
+     * {@link #trackListener(View, Object, int)}
+     * @param listenerResourceId A unique resource ID associated with the listener type.
+     * @return The previously tracked listener. This will be null if the View did not have
+     * a previously-tracked listener.
+     */
+    public static <T> T getListener(View view, int listenerResourceId) {
+        if (VERSION.SDK_INT >= VERSION_CODES.ICE_CREAM_SANDWICH) {
+            return (T) view.getTag(listenerResourceId);
+        } else {
+            synchronized (sListeners) {
+                WeakHashMap<View, WeakReference<?>> listeners = sListeners.get(listenerResourceId);
+                if (listeners == null) {
+                    return null;
+                }
+                final WeakReference<T> oldValue = (WeakReference<T>) listeners.get(view);
+                if (oldValue == null) {
+                    return null;
+                } else {
+                    return oldValue.get();
+                }
+            }
+        }
+    }
 }