android开发 PopupWindow 设置充满屏幕

View qrcode_view = this.getLayoutInflater().inflate(R.layout.taskdetail_qrcode,null);

                final PopupWindow qrcodePop = new PopupWindow(qrcode_view,getWindowManager().getDefaultDisplay().getWidth(),getWindowManager().getDefaultDisplay().getHeight());
                //qrcodePop.showAsDropDown(v);
                qrcodePop.showAtLocation(v,Gravity.CENTER,Gravity.FILL_HORIZONTAL,Gravity.FILL_VERTICAL);
                ImageView qrcode = (ImageView)qrcode_view.findViewById(R.id.qrcode_image);
                int qr_width = BitmapUtil.Dp2Px(this,200);
                qrcode.setImageBitmap(QRCodeUtil.createImage(globalVal.BASE_URL+"/"+taskInfo.task_id,qr_width,qr_width));
                qrcode_view.findViewById(R.id.close_qrcode).setOnClickListener(
                        new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                qrcodePop.dismiss();
                            }
                        }
                );

注意获取屏幕的高度和宽度：

宽度：getWindowManager().getDefaultDisplay().getWidth();

高度：getWindowManager().getDefaultDisplay().getHeight();