android PopupWindow 点击外面消失

最近工作需求需要用到PopupWindow ,MainActivity.java代码如下：

package com.example.administrator.popuwindow;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.PopupWindow;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity{

    private TextView textView;
    private   PopupWindow popupWindow;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
         textView = (TextView)findViewById(R.id.tv);
        textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                 popupWindow = new PopupWindow(LayoutInflater.from(MainActivity.this).inflate(R.layout.pop_list, null), ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT, true);
                popupWindow.showAtLocation(textView, Gravity.CENTER,0,0);
            }
        });
    }

  
}
pop_list.xml 如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="160dp"
    android:layout_height="160dp"
    android:orientation="vertical"
    android:background="#ffffff"
    android:gravity="center"
    tools:context="com.example.administrator.popuwindow.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="16dp"
        android:text="回复"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="16dp"
        android:text="删除"/>
</LinearLayout>

效果如图：

可是有个问题，只有按返回键才popuwindown才会消失，点击屏幕没有反应，在网上搜出的答案说是在

showAtLocation调用之前，加上以下两句，

popupWindow.setOutsideTouchable(true);
popupWindow.setBackgroundDrawable(new BitmapDrawable());
发现然并卵，百思不得其解，经过反复思考，发现这一段代码写得有问题：

popupWindow = new PopupWindow(LayoutInflater.from(MainActivity.this).inflate(R.layout.pop_list, null), ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT, true);
改成如下：

popupWindow = new PopupWindow(LayoutInflater.from(MainActivity.this).inflate(R.layout.pop_list, null), ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, true);
原因很简单，因为前者这样写得话，popupWindow 把整个window都遮挡了，所以popupWindow.setOutsideTouchable(true)并没有起到作用，所以失效