안드로이드 취소버튼 두번눌러 종료하기

 public class MainActivity extends Activity {
   
      private final long FINSH_INTERVAL_TIME    = 2000;
      private long  backPressedTime        = 0;
   
      @Override 
      protected void onCreate( Bundle savedInstanceState ) {
          super.onCreate( savedInstanceState );
          setContentView( R.layout.activity_main ); 
      } 
   
      @Override 
      public void onBackPressed() {
          long tempTime        = System.currentTimeMillis();
          long intervalTime    = tempTime - backPressedTime;
   
          if ( 0 <= intervalTime && FINSH_INTERVAL_TIME >= intervalTime ) {
              super.onBackPressed(); 
          } 
          else { 
              backPressedTime = tempTime; 
              Toast.makeText(getApplicationContext(),"'뒤로'버튼을한번더누르시면종료됩니다.",Toast.LENGTH_SHORT).show(); 
          } 
      } 
  }