Detect click on RecyclerView outside of items

Question

I have a RecyclerView with 2 items that don't fill the whole screen. How can I detect that the user clicked on the empty part of the RecyclerView (meaning clicked directly on the RecyclerView and not one of its items)?

Answer 1

如评论中所述

mRecyclerView.addOnItemTouchListener(new RecyclerView.OnItemTouchListener() {

  @Override
  public boolean onInterceptTouchEvent(RecyclerView recyclerView, MotionEvent motionEvent) {
    if (motionEvent.getAction() != MotionEvent.ACTION_UP) {
        return false;
    }
    View child = recyclerView.findChildViewUnder(motionEvent.getX(), motionEvent.getY());
    if (child != null) {
      // tapped on child
      return false;
    } else {
      // Tap occured outside all child-views.
      // do something
      return true;
    }
  }

  @Override
  public void onTouchEvent(RecyclerView recyclerView, MotionEvent motionEvent) {
  }
});

Answer 2

您可以子类化RecyclerView并覆盖该dispatchTouchEvent()方法来完成此任务.使用该findChildViewUnder()方法,我们可以确定触摸事件是否发生在子视图之外,并使用an interface来通知侦听器是否存在.在以下示例中,OnNoChildClickListener interface提供了该功能.

public class TouchyRecyclerView extends RecyclerView
{
    // Depending on how you're creating this View,
    // you might need to specify additional constructors.
    public TouchyRecyclerView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
    }

    private OnNoChildClickListener listener;
    public interface OnNoChildClickListener
    {
        public void onNoChildClick();
    }

    public void setOnNoChildClickListener(OnNoChildClickListener listener)
    {
        this.listener = listener;
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event)
    {
        // The findChildViewUnder() method returns null if the touch event
        // occurs outside of a child View.
        // Change the MotionEvent action as needed. Here we use ACTION_DOWN
        // as a simple, naive indication of a click.
        if (event.getAction() == MotionEvent.ACTION_DOWN
            && findChildViewUnder(event.getX(), event.getY()) == null)
        {
            if (listener != null)
            {
                listener.onNoChildClick();
            }
        }
        return super.dispatchTouchEvent(event);
    }
}

注:这适用于RecyclerView从我的答案在这里有关GridView.