MultiCallback.java 文件源码

@Override
public void scheduleDrawable(@NonNull final Drawable who, @NonNull final Runnable what, final long when) {
    for (int i = 0; i < mCallbacks.size(); i++) {
        final CallbackWeakReference reference = mCallbacks.get(i);
        final Callback callback = reference.get();
        if (callback != null) {
            callback.scheduleDrawable(who, what, when);
        } else {
            // Always remove null references to reduce Set size
            mCallbacks.remove(reference);
        }
    }
}