Question

如何获取回收者视图的项目的x / y。 mRecyclerView.getChildAt（1）使子项在位置1处可见。我希望将列表子项置于第一位置，以便在达到0,0时执行某些操作。

if(mRecyclerView.getChildAt(1).getTop() == 0){

//do some operation

}

我怎么能实现它？

Answer 1

有两种方法可以实现它：

创建您自己的LayoutManager（例如，会扩展LinearLayoutManager），将其附加到您的RecyclerView并在滚动时获得RecyclerView第一个子位置。< / p>

public class MyLinearLayoutManager extends LinearLayoutManager {

//Constructor stuff

@Override
public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
    if (getChildAt(1).getTop() == 0) {
        // do stuff...
    }
    return super.scrollVerticallyBy(dy, recycler, state);
}

@Override
public void onLayoutCompleted(RecyclerView.State state) {
    super.onLayoutCompleted(state);
    // check your stuff here too. It'll be called when new views appeared
}
}

将滚动侦听器附加到RecyclerView并获取其中的视图位置。

RecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            RecyclerView.ViewHolder holder = RecyclerView.findViewHolderForAdapterPosition(1);
            View view = holder.itemView;
            if (view.getTop() == 0){
                //...
            }
        }
    });

获取RecyclerView中“x”项的位置

1 个答案: