android从actionbar位置下方向滑出窗口PopupWindow

gif不是那么清晰，凑合着看哈O(∩_∩)O

                                         

 //以下是如何实现自定义弹出窗口，mView就是你想要展现的视图
        View mView = LayoutInflater.from(this).inflate(R.layout.click_booth_floating, null);
        WindowManager wm = this.getWindowManager();
        int width = wm.getDefaultDisplay().getWidth();
        //设置窗口的宽度
        mView.setMinimumWidth(width);
      /* 下面是对PopupWindow四个参数的详细介绍
       * @param contentView the popup's content
       * @param width the popup's width
       * @param height the popup's height
       * @param focusable true if the popup can be focused, false otherwise
       */
        PopupWindow popupWindow = new PopupWindow(mView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT , true);
        //获取AppBarLayout
        AppBarLayout appBar = (AppBarLayout) findViewById(R.id.map_activity_app_bar_layout);
        //点击popupwindow之外的地方，popupwindow消失
        popupWindow.setOutsideTouchable(true); 
        //由于Android 版本差异性,在不需要背景的情况下设置背景为透明
        popupWindow.setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.map_page_background)));
        //从appbar位置向下滑出PopupWindow
        popupWindow.showAsDropDown(appBar);