enter code here
Thread th=new Thread(new Runnable() {
        @Override
        public void run() {
            try { for(int i=0;i<5;i++) {
                b1.setText(""+i);
                Thread.sleep(5000);
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
       pp();
       
                        }
                    }
                });
            }} catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    });
    th.start();

如果你已经有了时间。

public class Timer {
    private float lastFrameChanged;
    private float frameDuration;
    private Runnable r;

    public Timer(float frameDuration, Runnable r) {
        this.frameDuration = frameDuration;
        this.lastFrameChanged = 0;
        this.r = r;
    }

    public void update(float dt) {
        lastFrameChanged += dt;

        if (lastFrameChanged > frameDuration) {
            lastFrameChanged = 0;
            r.run();
        }
    }
}

他是更简单的解决方案，工作在我的应用程序。

  public class MyActivity extends Acitivity {

    TextView myTextView;
    boolean someCondition=true;

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

            myTextView = (TextView) findViewById(R.id.refreshing_field);

            //starting our task which update textview every 1000 ms
            new RefreshTask().execute();



        }

    //class which updates our textview every second

    class RefreshTask extends AsyncTask {

            @Override
            protected void onProgressUpdate(Object... values) {
                super.onProgressUpdate(values);
                String text = String.valueOf(System.currentTimeMillis());
                myTextView.setText(text);

            }

            @Override
            protected Object doInBackground(Object... params) {
                while(someCondition) {
                    try {
                        //sleep for 1s in background...
                        Thread.sleep(1000);
                        //and update textview in ui thread
                        publishProgress();
                    } catch (InterruptedException e) {
                        e.printStackTrace(); 

                };
                return null;
            }
        }
    }

你也可以使用动画器:

int secondsToRun = 999;

ValueAnimator timer = ValueAnimator.ofInt(secondsToRun);
timer.setDuration(secondsToRun * 1000).setInterpolator(new LinearInterpolator());
timer.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()
    {
        @Override
        public void onAnimationUpdate(ValueAnimator animation)
        {
            int elapsedSeconds = (int) animation.getAnimatedValue();
            int minutes = elapsedSeconds / 60;
            int seconds = elapsedSeconds % 60;

            textView.setText(String.format("%d:%02d", minutes, seconds));
        }
    });
timer.start();

对于想要在kotlin中这样做的人:

val timer = fixedRateTimer(period = 1000L) {
            val currentTime: Date = Calendar.getInstance().time
            runOnUiThread {
                tvFOO.text = currentTime.toString()
            }
        }

为了停止计时器，你可以使用这个:

timer.cancel()

这个函数有许多其他选项，请尝试一下

这是一个定时器的简单代码:

Timer timer = new Timer();
TimerTask t = new TimerTask() {       
    @Override
    public void run() {

        System.out.println("1");
    }
};
timer.scheduleAtFixedRate(t,1000,1000);