What is the proper way to stop a service running as foreground

to start and stop a foreground service from an activity use :

//start
    Intent startIntent = new Intent(MainActivity.this, ForegroundService.class);
    startIntent.setAction(Constants.ACTION.STARTFOREGROUND_ACTION);
    startService(startIntent);
//stop
    Intent stopIntent = new Intent(MainActivity.this, ForegroundService.class);
    stopIntent.setAction(Constants.ACTION.STOPFOREGROUND_ACTION);
    startService(stopIntent);

in your foreground service - use (at least) this code:

@Override
 public int onStartCommand(Intent intent, int flags, int startId) {
    if (intent.getAction().equals(Constants.ACTION.STARTFOREGROUND_ACTION)) {
        Log.i(LOG_TAG, "Received Start Foreground Intent ");
        // your start service code
    }
    else if (intent.getAction().equals( Constants.ACTION.STOPFOREGROUND_ACTION)) {
        Log.i(LOG_TAG, "Received Stop Foreground Intent");
    //your end servce code
        stopForeground(true);
        stopSelfResult(startId);
    }
    return START_STICKY;
}

From your activity call startService(intent) and pass it some data that will represent a key to stop the service.

From your service call stopForeground(true) and then stopSelf() right after it.

As stated here: https://developer.android.com/guide/components/services#Stopping

A started service must manage its own lifecycle. That is, the system doesn't stop or destroy the service unless it must recover system memory and the service continues to run after onStartCommand() returns. The service must stop itself by calling stopSelf(), or another component can stop it by calling stopService().

Once requested to stop with stopSelf() or stopService(), the system destroys the service as soon as possible.

So you can call stopService() from the activity that you used to call startService(). I have done that right here:

start_button.setOnClickListener {
            applicationContext.startForegroundService(Intent(this, ServiceTest::class.java))
        }
stop_button.setOnClickListener {
            applicationContext.stopService(Intent(this, ServiceTest::class.java))
        }

I created two buttons to start and stop the service and it works.