popupwindow focus problem solution

1. Problem: if PopupWindow is created, listView should be displayed in it. In this case, itemClick of listView must be focused to achieve PopupWindow.
2. Resolution: PopupWindow gets focus: window.setFocusable(true);
window.setBackgroundDrawable(new BitmapDrawable());
3. Note: if it still can't be realized, the above two sentences of code change the order ~~~