@Override
  public synchronized void onFinalImageSet(
      String id, @Nullable INFO imageInfo, @Nullable Animatable animatable) {
    final int numberOfListeners = mListeners.size();
    for (int i = 0; i < numberOfListeners; ++i) {
      try {
        ControllerListener<? super INFO> listener = mListeners.get(i);
        if (listener != null) {
          listener.onFinalImageSet(id, imageInfo, animatable);
        }
      } catch (Exception exception) {
        // Don't punish the other listeners if we're given a bad one.
        onException("InternalListener exception in onFinalImageSet", exception);
      }
    }
  }
Listener that forwards controller events to multiple listeners.
drawee/src/main/java/com/facebook/drawee/controller/ForwardingControllerListener.java