java - 检查 smoothScrollToPosition 何时完成

Question

我想检查 smoothScrollToPosition 何时完成滚动回到 recyclerview 的第一项。我试过这样做，只有在 smoothScrollToPosition 仍在滚动时才有效:

recyclerView.getLayoutManager().smoothScrollToPosition(recyclerView,new RecyclerView.State(), 0);
if (!recyclerView.getLayoutManager().isSmoothScrolling()) {
    Log.d(TAG, "Scrolling has ended.");
} 

Answer 1

我使用 onScrollStateChanged(RecyclerView recyclerView, int newState) 方法来跟踪滚动状态。启动滚动的方法如下所示:

private void scrollToPosition(int position){
    recyclerView.removeOnScrollListener(onScrollListener);
    recyclerView.addOnScrollListener(onScrollListener);
    recyclerView.smoothScrollToPosition(position);
}

这是监听器:

RecyclerView.OnScrollListener onScrollListener = new RecyclerView.OnScrollListener() {
       @Override
       public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
           switch (newState) {
               case SCROLL_STATE_IDLE:
                   //we reached the target position
                   recyclerView.removeOnScrollListener(this);
                   break;
           }
       }
   };

因此，当 recyclerView 到达 SCROLL_STATE_IDLE 时，这意味着它已经完成滚动。不要忘记在此状态下移除监听器，因此它不会在下一次滚动时触发。