Android点击按钮退出程序并提醒

效果展示：

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

            Button exitButton;

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

                exitButton = (Button)findViewById(R.id.exit);
                exitButton.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this)
                                .setTitle("退出程序")
                                .setMessage("是否退出程序")
                                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialogInterface, int i) {
                                        finish();
                                    }
                                })
                                .setNegativeButton("取消", new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialogInterface, int i) {
                                        return;
                                    }
                                }).create();
                        alertDialog.show();
                    }
                });
            }
        }

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/exit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="退出"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>