Question

我想构建一个5秒钟的计时器，在1秒钟的间隔内计数到0，然后重置为5秒的初始值。计时器需要不断运行。看完这个帖子后， Android - loop part of the code every 5 seconds

我使用了CountDownTimer类并在onFinish（）方法中调用了start（）方法，这样当计时器结束时，它会重置为5.它会在连续循环上运行，但是我注意到在第一个循环之后，它要么倒计时4-3-2-1-0或5-3-2-1-0。有人可以向我解释为什么会这样吗？

private long START_TIME_IN_MILLIS = 5000;
//set up our variables
private CountDownTimer timer;
private TextView textView;
private Button starttimer;
private long mTimeLeftInMillis = START_TIME_IN_MILLIS;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);
    textView = findViewById(R.id.text_view_countdown);
    starttimer = findViewById(R.id.button_start_pause);
    //set onclik listener when touch imput button
    starttimer.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            beginTime();
        }
    });
}

//creating my own method
private void beginTime() {

    timer = new CountDownTimer(mTimeLeftInMillis, 1000) {

        @Override
        public void onTick(long millisUntilFinished) {
            mTimeLeftInMillis = millisUntilFinished;
            updateCountDownText();
        }

        @Override
        public void onFinish() {
            start();
        }

    }.start();
}

private void updateCountDownText(){
    int minutes= (int) (mTimeLeftInMillis / 1000)/ 60;
    int seconds= (int) (mTimeLeftInMillis / 1000) % 60;

    String timeLeftFormatted = String.format(Locale.getDefault(),"%02d:%02d", minutes, seconds);
    textView.setText(timeLeftFormatted);
}

}

Answer 1

试试这个

 @Override
        public void onFinish() {
          mTimeLeftInMillis = START_TIME_IN_MILLIS;
   }

为什么定时器循环在调用onFinish（）方法时没有初始化为初始值？

1 个答案: