안드로이드) 뒤로가기 2번 누르면 종료되게 하기

 

 

public class MainActivity extends AppCompatActivity {
    final Context context = this;
    private BackKeyClickHandler backKeyClickHandler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        backKeyClickHandler = new BackKeyClickHandler(this);
    }

    @Override
    public void onBackPressed() {
        backKeyClickHandler.onBackPressed();
    }

    public class BackKeyClickHandler {
        private long backKeyClickTime = 0;
        private Activity activity;
        public BackKeyClickHandler(Activity activity) { this.activity = activity; }
        public void onBackPressed() {
            if (System.currentTimeMillis() > backKeyClickTime + 2000) {
                backKeyClickTime = System.currentTimeMillis();
                showToast(); return;
            }
            if (System.currentTimeMillis() <= backKeyClickTime + 2000) activity.finish();
        }
        public void showToast() {
            Toast.makeText(activity, "뒤로 가기 버튼을 한 번 더 누르면 종료됩니다.", Toast.LENGTH_SHORT).show();
        }
    }
}