PopupWindow 弹出时背景变暗

下面的PopupWindow  的高是相对于屏幕高设计，宽是获取的某一个控件的宽设置，位置位于某控件的上方，红色部分是设置弹出时屏幕变暗的。

 　　　　 //设置contentView
         View contentView = LayoutInflater.from(this).inflate(R.layout.popwindow_submit, null);
         photoPopWindow = new PopupWindow(contentView, WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.MATCH_PARENT, true);
         photoPopWindow.setContentView(contentView);
         //获取屏幕宽高度
         DisplayMetrics dm = this.getResources().getDisplayMetrics();
         int screenWidth = dm.widthPixels;
         int screenHeight = dm.heightPixels;
         //根据屏幕宽高度设置popwindow大小
         photoPopWindow.setWidth((int)(upload.getWidth()));
         photoPopWindow.setHeight((int)(screenHeight * 0.13));

         //设置各个控件的点击响应
         rl_takePhoto = contentView.findViewById(R.id.rl_takePhoto);
         rl_choicePhoto = contentView.findViewById(R.id.rl_choicePhoto);
         rl_takePhoto.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
                 keep.setBackgroundColor(getResources().getColor(R.color.white));
                 upload.setBackgroundColor(getResources().getColor(R.color.color_success));
                 paste.setBackgroundColor(getResources().getColor(R.color.white));
                 submit();
                 //上传数据
                 photoPopWindow.dismiss();
             }
         });
         rl_choicePhoto.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
                 submitPhoto();
                 //上传图片
                 photoPopWindow.dismiss();
             }
         });
         int[] location = new int[];
         //在控件上方显示
         int[] location1 = new int[];
         upload.getLocationOnScreen(location);
         //photoPopWindow.showAtLocation(upload,Gravity.NO_GRAVITY, location1[0],location1[1]-photoPopWindow.getHeight());
         photoPopWindow.showAtLocation(upload,Gravity.NO_GRAVITY, location1[]+upload.getWidth(),screenHeight-photoPopWindow.getHeight()-upload.getHeight());

         // 设置背景颜色变暗
         WindowManager.LayoutParams lp = this.getWindow().getAttributes();
         lp.alpha = 0.7f;
         this.getWindow().setAttributes(lp);
         photoPopWindow.setOnDismissListener(new PopupWindow.OnDismissListener() {

             @Override
             public void onDismiss() {
                 WindowManager.LayoutParams lp = getWindow().getAttributes();
                 lp.alpha = 1f;
                 getWindow().setAttributes(lp);
             }
         });