<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_horizontal"
    android:background="@mipmap/dialog_bg">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="真的要退出吗?"
        android:textSize="34sp"
        android:textColor="#e61414"
        android:textStyle="bold"
        android:layout_marginTop="265dp"/>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_margin="25dp">

        <ImageView
            android:id="@+id/yes_btn"
            android:layout_width="120dp"
            android:layout_height="50dp"
            android:src="@mipmap/yes_btn"
            />

        <ImageView
            android:id="@+id/no_btn"
            android:layout_width="120dp"
            android:layout_height="50dp"
            android:src="@mipmap/no_btn"
         />

    </LinearLayout>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="mydialog" parent="android:style/Theme.Dialog">
        <item name="android:windowNoTitle">true</item>
        <item name="android:windowBackground">@android:color/transparent</item>
    </style>
</resources>

package com.example.dialog;

import android.app.Dialog;
import android.content.Context;
import android.view.View;

import androidx.annotation.NonNull;

//1.设计自定义对话框样式-->dialog_layout.xml
//2.设计style(去标题栏，去背景)
//3.将第一步的布局应用到当前自定义对话框
//4.实例化对话框(参数1:环境上下文 参数2:第二步创建的style R.style.mydialog),并展示show 
public class Mydialog extends Dialog {

    public Mydialog(@NonNull Context context, int themeResId) {
        super(context, themeResId);
        setContentView(R.layout.dialog_layout);

        findViewById(R.id.yes_btn).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                System.exit(0);
            }
        });

        findViewById(R.id.no_btn).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dismiss(); //对话框消失
            }
        });
    }

}

package com.example.dialog;

import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

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

    public void showNormalDialog(){
        AlertDialog dialog = new AlertDialog.Builder(this).create();
        dialog.setTitle("提示");
        dialog.setMessage("您确定要退出程序吗？");
        dialog.setButton(DialogInterface.BUTTON_POSITIVE, "确定", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {

            }
        });
        dialog.show();
    }


    public void myClick(View view) {
        switch (view.getId()) {
            case R.id.normal_dialog_btn:
                //1.实例化一个Buidler
                //AlertDialog的构造方法时protected
                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                //2.设置对话框样式
                builder.setTitle("提示");
                builder.setMessage("您确定退出程序吗?");
                builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        finish();
                    }
                });
                //展示 
                builder.setNegativeButton("取消", null);
                builder.show();
//                AlertDialog dialog = builder.create();
//                dialog.show();
                break;

            case R.id.diy_dialog_btn:
                Mydialog md = new Mydialog(this, R.style.mydialog);
                md.show();
                break;
        }
    }
}