GifFrameLoader.java 文件源码

@VisibleForTesting
void onFrameReady(DelayTarget delayTarget) {
  if (onEveryFrameListener != null) {
    onEveryFrameListener.onFrameReady();
  }
  isLoadPending = false;
  if (isCleared) {
    handler.obtainMessage(FrameLoaderCallback.MSG_CLEAR, delayTarget).sendToTarget();
    return;
  }
  // If we're not running, notifying here will recycle the frame that we might currently be
  // showing, which breaks things (see #2526). We also can't discard this frame because we've
  // already incremented the frame pointer and can't decode the same frame again. Instead we'll
  // just hang on to this next frame until start() or clear() are called.
  if (!isRunning) {
    pendingTarget = delayTarget;
    return;
  }

  if (delayTarget.getResource() != null) {
    recycleFirstFrame();
    DelayTarget previous = current;
    current = delayTarget;
    // The callbacks may unregister when onFrameReady is called, so iterate in reverse to avoid
    // concurrent modifications.
    for (int i = callbacks.size() - 1; i >= 0; i--) {
      FrameCallback cb = callbacks.get(i);
      cb.onFrameReady();
    }
    if (previous != null) {
      handler.obtainMessage(FrameLoaderCallback.MSG_CLEAR, previous).sendToTarget();
    }
  }

  loadNextFrame();
}