(七十三) PopupWindow的使用

    /**
     * 创建一个PopupWindow
     */
    private void createPopupWindow() {
        LayoutInflater layoutInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View view = layoutInflater.inflate(R.layout.popup_window_layout, null);
        popupWindow = new PopupWindow(view, LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT);
        // 产生activity背景变暗效果
        WindowManager.LayoutParams lp = getWindow().getAttributes();
        lp.alpha = 0.4f;
        getWindow().setAttributes(lp);
        popupWindow.setFocusable(true);// PopUpWindow可以看作一个类似于模态对话框的东西，如果设置是false只是一个浮现在当前界面上的view而已，不影响当前界面的任何操作
        popupWindow.setOutsideTouchable(true); // 点击popWin以处的区域，自动关闭
        ColorDrawable cd = new ColorDrawable(0x000000);
        popupWindow.setBackgroundDrawable(cd); // 如果不设置PopupWindow的背景，点击外部区域无法dismiss弹框，不能触发OnDismissListener
        popupWindow.setAnimationStyle(R.style.PopupWindowAnimation);
        popupWindow.showAsDropDown(titleBarView, titleBarView.getWidth()
                - popupWindow.getWidth(), 0);// 设置好参数之后再show
        popupWindow.update(); // 刷新状态
        // 监听PopupWindow被dismiss的时候，恢复activity透明度
        popupWindow.setOnDismissListener(new OnDismissListener() {
            @Override
            public void onDismiss() {
                WindowManager.LayoutParams lp = getWindow().getAttributes();
                lp.alpha = 1f;
                getWindow().setAttributes(lp);
            }
        });
    }