java我如何无法在Gridlayout中再次设置可见？

Question

我的Imageview在网格布局中，当我触摸imageview时，我有一个ontouchlisteners，我将其设置为不可见，当我将imageview放到屏幕上时，我有一个DragListener

Error(ConcurrentModificationException)

当我放下图像视图时，ImageviewI Touch再次设置为可见

我怎样才能做到这一点

这是我的密码

   @Override
public boolean onDrag(View v, DragEvent event) {
    int dragEvent = event.getAction();
    final View views = (View)event.getLocalState();
    switch (dragEvent) {
  case DragEvent.ACTION_DRAG_ENTERED:
            break;

  case DragEvent.ACTION_DRAG_EXITED:
            break;

   case DragEvent.ACTION_DROP:
            views.setVisibility(View.VISIBLE);
            break;

        case DragEvent.ACTION_DRAG_ENDED:
            views.setVisibility(View.VISIBLE);

            break;
    }
    return true;
}

@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
    if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
        ClipData data = ClipData.newPlainText("", "");
        View.DragShadowBuilder myshadowBuilder = new View.DragShadowBuilder(view);
        view.startDrag(data, myshadowBuilder, view, 0);
        view.setVisibility(View.INVISIBLE);
        return true;
    } else {
        return false;
    }
}