Android AlertDialog 알림 대화상자 보여주기

package com.example.sampledialog;

import android.content.DialogInterface;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import org.w3c.dom.Text;

import butterknife.BindView;
import butterknife.ButterKnife;

public class MainActivity extends AppCompatActivity {
    @BindView(R.id.button)
    Button button;
    @BindView(R.id.textView)
    TextView textView;

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

        button.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view){
                showMessage();
            }
        });
    }
    public void showMessage(){
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("안내");
        builder.setMessage("종료할꼬얌?");
        builder.setIcon(android.R.drawable.ic_dialog_alert);
        builder.setPositiveButton("예", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                String message="예 버튼이 눌렸습니다. ";
                textView.setText(message);
            }
        });
        builder.setNeutralButton("취소", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                String message="취소 버튼이 눌렸습니다. ";
                textView.setText(message);
            }
        });
        builder.setNegativeButton("아니요", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                String message="아니요 버튼이 눌렸습니다. ";
                textView.setText(message);
            }
        });
        AlertDialog dialog=builder.create();
        dialog.show();
    }
}

Activity

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="띄우기"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:layout_marginBottom="8dp"
        android:text="버튼을 누르면 대화상자가 뜹니다."
        android:textSize="25sp"
        app:layout_constraintBottom_toTopOf="@+id/button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

xml

혼자 하다 심심해서 귀여운말투썻는데 혹시나 이글 보시는 분들은 역겹게해서 죄송 ㅎㅎ;