App doesn't respond when I run while loop in onStartCommand() in my service

Question

This is my code:

 @Override
public void onCreate() {
    super.onCreate();
    //Log.i("TAG", "ovdje smo");
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    Log.i("alo", "bre");
     telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
     cellLocation = (GsmCellLocation) telephonyManager.getCellLocation();
    oldCellID = cellLocation.getCid();

    while( true ){
        Log.i("jesmo li tu",""+oldCellID);
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
        Toast.makeText(this, "Kupimo cell ID OLD" + oldCellID, Toast.LENGTH_SHORT).show();
        telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
        cellLocation = (GsmCellLocation) telephonyManager.getCellLocation();
        newCellID = cellLocation.getCid();

        if(oldCellID != newCellID){
            //TODO uzmi lokaciju + spremi u bazu
            Log.i("usli u petlju", "DA"+newCellID + oldCellID);
            Toast.makeText(this, "Stari id ->" + oldCellID + " noviCellID -> " + newCellID, Toast.LENGTH_SHORT).show();
            oldCellID = newCellID;
            telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
            cellLocation = (GsmCellLocation) telephonyManager.getCellLocation();
            newCellID = cellLocation.getCid();
        }


    }

It looks good in Log, but app doesn't response. It looks like this: App doesn't respond I'm new at android, Can I use something else, listener ?? I want to track when my CellID change value and then get current location.

score 6 · Accepted Answer · answered May 26 '17 at 11:37

onStartCommand runs on UI Thread, That's why your app doesn't respond. Either you can start a Thread from onStartCommand and execute the actual task. Otherwise you can go for IntentService

Refer https://developer.android.com/reference/android/app/Service.html https://developer.android.com/reference/android/app/IntentService.html

Denny · Answer 2 · 2017-05-26T11:43:36.490

1

You have a while (true) with a Thread.sleep(3000); so it's freezing your app because it keeps looping and waiting on the main UI thread.

You should use an AlarmManager to do things periodically.

Here is a good start: Alarm Manager Example

Using loops like while (true) is generally bad practice. Only situation I can think of at the moment is using it when programming in embedded systems.

edited May 26 '17 at 11:43

answered May 26 '17 at 11:38

Denny

1,766
3
17
37

score 0 · Answer 3 · answered May 26 '17 at 12:49

Make use of intent service to run the while block in onHandleIntent() to avoid ANR(application not responding). As of now your code is blocking UI.

Note : In Android O, starting a service while application is in background will throw IllegalStateException. You have to use Firebase Job dispatcher instead of Service

App doesn't respond when I run while loop in onStartCommand() in my service

3 Answers3