Can I run a stopwatch in an Andriod notification?

[Darkmisc]

TL;DR Summary

I've tried to run a stopwatch in a notification by constantly updating the text, but it only seems to tick over every second or so. The stopwatch is supposed to tick over every hundredth of a second. It will stop updating after about 20s and program will end.

Hi everyone

I'm making a stopwatch app and I'd like the timer to continue showing on the lock screen. I've used a notification for this, but it's not working properly. The lock screen stopwatch only updates every second or so, whereas in the app, the stopwatch ticks over every hundredth of a second. The lock screen only updates for about 20s before it freezes. The app stops working at this point. There is no logcat message when this happens.

Also, the lock screen timer shows a time of 4847:38:68 when it should be 00:38:68. I've used the same code for the lock screen timer as the in app timer. I don't know why the in app timer starts from 00:00:00, whereas the lock screen timer starts from 4847:00:00.

Does anyone know what I've done wrong? Should I be using something other than a notification?

Thanks

EDIT: I've deleted Thread.sleep(2000) part of the code and the lock screen timer still updates only every second or so.

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.SystemClock;
import android.util.Log;


import androidx.annotation.Nullable;
import androidx.core.app.NotificationCompat;


public class MyForegroundService extends Service {

    long MillisecondTime, StartTime, TimeBuff, UpdateTime = 0L ;
    Handler handler;
    String time;
    int Seconds, Minutes, MilliSeconds ;
    final String CHANNELID = "Foreground Service ID";
    NotificationChannel channel = new NotificationChannel(
            CHANNELID,
            CHANNELID,
            NotificationManager.IMPORTANCE_LOW
    );

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        new Thread(
                new Runnable() {
                    @Override
                    public void run() {
                        while (true) {
                            Log.e("Service", "Service is running...");
                            try {
                                Thread.sleep(2000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }
        ).start();

        handler = new Handler() ;

        handler.postDelayed(runnable, 0);

    }



    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    public Runnable runnable = new Runnable() {

        public void run() {

            MillisecondTime = SystemClock.uptimeMillis() - StartTime;
            UpdateTime = TimeBuff + MillisecondTime;
            Seconds = (int) (UpdateTime / 1000);
            Minutes = Seconds / 60;
            Seconds = Seconds % 60;
            MilliSeconds = (int) (UpdateTime % 1000);
            time = Minutes + ":"
                    + String.format("%02d", Seconds) + ":"
                    + String.format("%02d", MilliSeconds/10);
            NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(MyForegroundService.this, CHANNELID);
            mBuilder.setContentTitle("asfad Point");
            mBuilder.setSmallIcon(R.drawable.ic_launcher_foreground);
            mBuilder.setContentText(time);
          
            NotificationManager mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            mNotificationManager.notify(1, mBuilder.build());



            handler.postDelayed(this, 0);
        }

    };



}

 

[Greg Bernhardt]

Perhaps Android has some built in contraint not allow a notification update more than once a second?

 

[Wrichik Basu]

The only way to update the time in the notification is to re-create and re-post the notification. And the rate limit is 60 Hz.

https://stackoverflow.com/a/57120044/8387076