앱만들기.22(뒤로가기 두번눌러 앱종료)

package com.example.backbuttonexample;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {


    private long backBtnTime = 0;



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


    @Override
    public void onBackPressed() {
        long curTime = System.currentTimeMillis();
        long gapTime = curTime - backBtnTime;
        //이 시간내에 누르게 되면 앱이 꺼짐
        if(0 <=gapTime && 2000>=gapTime){
            super.onBackPressed();
        }
        else{
            backBtnTime = curTime;
            Toast.makeText(this,"한번 더 누르면 종료됩니다요",Toast.LENGTH_SHORT).show();

        }

    }
}