PopupWindow阻塞式對話框

package com.zdsoft.popupwindow1130;

import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.PopupWindow;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private Button bt_show, bt_login, bt_exit;
    private EditText et_user, et_password;
    private View myView;

    private PopupWindow popupWindow;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        initListener();

    }

    private void initView() {
        bt_show = (Button) findViewById(R.id.bt_show);
        //將佈局文件轉換爲View
        myView = LayoutInflater.from(MainActivity.this).inflate(R.layout.popupwindow_view, null);
        //獲取自定義佈局中的控件
        et_user = (EditText) myView.findViewById(R.id.et_user);
        et_password = (EditText) myView.findViewById(R.id.et_password);
        bt_login = (Button) myView.findViewById(R.id.bt_login);
        bt_exit = (Button) myView.findViewById(R.id.bt_exit);
    }

    private void initListener() {
        bt_login.setOnClickListener(this);
        bt_exit.setOnClickListener(this);
        bt_show.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.bt_login:
                Toast.makeText(MainActivity.this, et_user.getText().toString(), Toast.LENGTH_SHORT).show();
                popupWindow.dismiss();
                break;
            case R.id.bt_exit:
                //關閉彈出窗口
                popupWindow.dismiss();
                break;
            case R.id.bt_show:
                //實例化PopupWindow
                popupWindow = new PopupWindow(myView, 600, 400);
                //設置可以聚焦
                popupWindow.setFocusable(true);
                //設置背景顏色
                popupWindow.setBackgroundDrawable(ContextCompat.getDrawable(MainActivity.this, R.color.colorAccent));
                //顯示彈出窗口
                popupWindow.showAtLocation(myView, Gravity.CENTER, 0, 0);
                break;
            default:
                break;
        }

    }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.zdsoft.popupwindow1130.MainActivity">

    <Button
        android:id="@+id/bt_show"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="登錄按鈕" />
</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="10dp"
    android:gravity="center">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="賬號"/>
        <EditText
            android:id="@+id/et_user"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:hint="請輸入賬號"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingTop="20dp"
        android:paddingBottom="10dp">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="密碼"/>
        <EditText
            android:id="@+id/et_password"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_height="wrap_content"
            android:hint="請輸入密碼"
            android:inputType="textPassword"/>
    </LinearLayout>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
        <Button
            android:id="@+id/bt_login"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="登錄"
            android:layout_marginRight="60dp"/>
        <Button
            android:id="@+id/bt_exit"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="取消"/>
    </LinearLayout>

</LinearLayout>