Activity启动的时候弹出popupwindow

1.做延迟

2.在onwindowFocusChanged方法中弹出

@Override
public void onWindowFocusChanged(boolean hasFocus) {
    super.onWindowFocusChanged(hasFocus);
    popupWindow.showAtLocation(popupView, Gravity.CENTER, 0, 0);
    backgroundAlpha(0.2f);
}