只需通过传递秒和textview对象调用下面的函数

public void reverseTimer(int Seconds,final TextView tv){

    new CountDownTimer(Seconds* 1000+1000, 1000) {

        public void onTick(long millisUntilFinished) {
            int seconds = (int) (millisUntilFinished / 1000);
            int minutes = seconds / 60;
            seconds = seconds % 60;
            tv.setText("TIME : " + String.format("%02d", minutes)
                    + ":" + String.format("%02d", seconds));
        }

        public void onFinish() {
            tv.setText("Completed");
        }
    }.start();
}

试试这个方法:

private void startTimer() {
    startTimer = new CountDownTimer(30000, 1000) {

        public void onTick(long millisUntilFinished) {

            long sec = (TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished) -
 TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished)));

            Log.e(TAG, "onTick: "+sec );
            tv_timer.setText(String.format("( %02d SEC )", sec));
            if(sec == 1)
            {

                new Handler().postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        tv_timer.setText("( 00 SEC )");
                    }
                }, 1000);
            }


        }

        public void onFinish() {
            tv_timer.setText("Timer finish");
        }
    }.start();
}

如CountDownTimer的文档所示:

new CountDownTimer(30000, 1000) { onTick(long milliseconds untilfinished) { mTextField。setText("seconds remaining: " + msuntilfinished / 1000); //逻辑来设置EditText可以在这里 ｝ onFinish() { mTextField.setText(“完成了!”); ｝ } .start ();

public class Scan extends AppCompatActivity {
int minute;
long min;
TextView tv_timer;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_scan2);
    tv_timer=findViewById(R.id.tv_timer);
    minute=Integer.parseInt("Your time in string form like 10");
    min= minute*60*1000;
    counter(min);
}
private void counter(long min) {
    CountDownTimer timer = new CountDownTimer(min, 1000) {
        public void onTick(long millisUntilFinished) {
            int seconds = (int) (millisUntilFinished / 1000) % 60;
            int minutes = (int) ((millisUntilFinished / (1000 * 60)) % 60);
            int hours = (int) ((millisUntilFinished / (1000 * 60 * 60)) % 24);
            tv_timer.setText(String.format("%d:%d:%d", hours, minutes, seconds));
        }
        public void onFinish() {
            Toast.makeText(getApplicationContext(), "Your time has been completed",
                    Toast.LENGTH_LONG).show();
        }
    };
    timer.start();
}

}

我用kotlin流实现了一个很酷的定时器方法，所以你可以在ViewModel中实现它

    var countDownInit = 30
    fun countDownTimer() = flow<Int> {
    var time = countDownInit
    emit(time)
    while (true){
        time--
        delay(1000L)
        countDownInit = time
        emit(time)
    }
}

然后在你的activity或fragment中像这样调用这个函数

lifecycleScope.launch {
        lifecycle.repeatOnLifecycle(Lifecycle.State.STARTED){
                 viewModel.countDownTimer().collect{time->
                      //and update UI 
                     //and for the finish section you can just use this
                     this.cancel()          
                 }
        }
}

现在在应用程序生命周期的暂停阶段会出现崩溃，你总是有最新的时间

下面是我在Kotlin中使用的解决方案

private fun startTimer()
{
    Log.d(TAG, ":startTimer: timeString = '$timeString'")

    object : CountDownTimer(TASK_SWITCH_TIMER, 250)
    {
        override fun onTick(millisUntilFinished: Long)
        {
            val secondsUntilFinished : Long = 
            Math.ceil(millisUntilFinished.toDouble()/1000).toLong()
            val timeString = "${TimeUnit.SECONDS.toMinutes(secondsUntilFinished)}:" +
                    "%02d".format(TimeUnit.SECONDS.toSeconds(secondsUntilFinished))
            Log.d(TAG, ":startTimer::CountDownTimer:millisUntilFinished = $ttlseconds")
            Log.d(TAG, ":startTimer::CountDownTimer:millisUntilFinished = $millisUntilFinished")
        }

        @SuppressLint("SetTextI18n")
        override fun onFinish()
        {
            timerTxtVw.text = "0:00"
            gameStartEndVisibility(true)
        }
    }.start()
}