mMap.addPolyline throws illegalstateexception

Question

I have a service that listens to location changes and sends message to UI thread together with Polylineoptions, it goes like this:

    //some code here
    Bundle bundle = new Bundle();
    bundle.putParcelable("polylineOptions", mPolylineOptions);
    Message msg = Message.obtain(null, LOCATION_UPDATE);
    msg.setData(bundle);
    mMainHandler.dispatchMessage(msg);
    //some more code

mPolylineOptions contains new location together with all previous locations. in the main thread i have handleMessage method that should update my map. it gos like this:

    private class MainHandler extends Handler {

     private MainHandler (Looper looper){
         super(looper);
     }
     @Override
     public void handleMessage (Message msg){
        switch (msg.what){
        case TrackingService.LOCATION_UPDATE:
            if (D){Log.d(TAG, "Location update received");};
            myPolylineOptions = (PolylineOptions) msg.getData().getParcelable("polylineOptions");
            new Color();
            myPolyline = mMap.addPolyline(myPolylineOptions
                    .color(Color.argb(128, 255, 0, 0))
                    .geodesic(true));
            break;
        }
     }
 }

i can see that handler receives the message, but I get "illegalstateexception: Not On The Main Thread" when i call

    myPolyline = mMap.addPolyline(myPolylineOptions
                .color(Color.argb(128, 255, 0, 0))
                .geodesic(true));

Anybody has ideas how to solve this? Thanks!

EDIT:

I bound to service and pass to it my UI Handler like this:

    private ServiceConnection mConnection = new ServiceConnection() {
    // Called when the connection with the service is established
    public void onServiceConnected(ComponentName className, IBinder service) {
        if (D) {Log.d(TAG, "main - onServiceConnected started");};
        // Because we have bound to an explicit
        // service that is running in our own process, we can
        // cast its IBinder to a concrete class and directly access it.
        LocalBinder binder = (LocalBinder) service;
        mService = binder.getService();
        mBound = true;
        while (mService.getThreadHandler() == null){
            try {
                Thread.sleep(100);
                if(D) {Log.d(TAG, "Thread Handler is not ready");};
            } catch (Exception e){}
        }
        mThreadHandler = mService.getThreadHandler();
        mService.setHandler(new MainHandler(Looper.getMainLooper()));

    }

Code for a thread. this thread runs in a service:

I know, this thread class is very "dirty" inelegant and unprofessional....

    private class ThreadHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what){
            case MAIN_HANDLER:
                if(D) {Log.d(TAG, "main hadler received");};
                break;
            }
            super.handleMessage(msg);
        }
    }

    public LocationThread (Context context){
        mContext = context;
        keepOn = true;
    }

    public void cancel() {
        keepOn = false;
        if (D){Log.d(TAG, "thread was canceled");}; 
    }

    public void run(){
        try {
            Looper.prepare();
        } catch (Exception e) {}
        // create handler for communication
        mThreadHandler = new ThreadHandler();
        // setup location updates
        Location mLocation;
        Location lastLocation = null;
        PolylineOptions mPolylineOptions = new PolylineOptions();
        mLocationRequest = LocationRequest.create();
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY); // Use high accuracy 
        mLocationRequest.setInterval(UPDATE_INTERVAL); // Set the update interval to 5 seconds 
        mLocationRequest.setFastestInterval(FASTEST_INTERVAL); // Set the fastest update interval to 1 second
        mLocationClient = new LocationClient(mContext, this, this);
        mLocationClient.connect();

        while (keepOn){
            try {
                Thread.sleep(10000);
            } catch (Exception e){}
            if (mConnected){
                if (D) {Log.d(TAG, "thread is running");};
                mLocation = mLocationClient.getLastLocation();
                if (lastLocation == null) {
                    LatLng mLatLng = new LatLng(mLocation.getLatitude(), mLocation.getLongitude());
                    mPolylineOptions.add(mLatLng);
                    lastLocation = mLocation;
                }
                // Report to the UI that the location was updated
                float distance = mLocation.distanceTo(lastLocation);
                if (distance > 1){
                    LatLng mLatLng = new LatLng(mLocation.getLatitude(), mLocation.getLongitude());
                    mPolylineOptions.add(mLatLng);
                    new Color();
                    lastLocation = mLocation;
                }

                if (hasBindedActivity){
                    Bundle bundle = new Bundle();
                    bundle.putParcelable("polylineOptions", mPolylineOptions);
                    Message msg = Message.obtain(null, LOCATION_UPDATE);
                    msg.setData(bundle);
                    mMainHandler.dispatchMessage(msg);
                }
            }

        }

        Looper.loop();
    }

The whole getThreadHandler thing seems unnecessary to me based on this code. I think you can first of all use the constructor without parameters for your MainHandler (no need to give it the looper). Then just create a new handler by calling `mMainHandler = new MainHandler();` from within the onServiceConnected (which runs on UI thread). — J.Nieminen, Oct 28 '13 at 21:21
Hmm.. I tried to create mMainHandler without any looper provided before posting this question. still same result. — PauliusM, Oct 28 '13 at 21:35
Can you add the whole code? Now I can, for example, only see `mThreadHandler` being initialised, but the constructor for the `mMainHandler` is not shown. — J.Nieminen, Oct 28 '13 at 21:38

J.Nieminen · Answer 1 · 2013-10-28T21:27:39.890

0

For me it looks like your mMainHandler is constructed outside the GUI thread. Make sure that you call mMainHandler = new MainHandler(); from within the GUI thread because Handler callbacks are executed in the thread where the Handler was created.

Edit: As Robin said, as long as you are just planning to update the UI based on some background activity, you should use for example an AsyncTask instead of a service. Simply create a private class extending AsyncTask within your Activity, do the background stuff in doInBackground and then update the GUI in onPostExecute, which runs again in the GUI thread. See http://developer.android.com/reference/android/os/AsyncTask.html for more info.

edited Oct 28 '13 at 21:27

answered Oct 28 '13 at 21:10

J.Nieminen

566
5
12

I create Handler and pass it to my service on onServiceConnected method. is that OK? – PauliusM Oct 28 '13 at 21:22
Thanks for a suggestion about asyncTask, but I REALLY need service this time. Any ideas why my implementation is not working? Am I creating Handler in a right way? – PauliusM Oct 28 '13 at 21:31
Okay, but why exactly do you need a service for this? In any case, here's another question that might help: http://stackoverflow.com/questions/14695537/android-update-activity-ui-from-service – J.Nieminen Oct 28 '13 at 21:34
Service should listen for location updates even after app is killed. I know, maybe its not good idea because of the power consumption and maybe there are other ways to do that without service, but i feel like i am close to finish, all i need is to update my UI after receiving location updates. – PauliusM Oct 28 '13 at 21:40
But there's no need to update a GUI if the app is no longer visible. So I would try to decouple the logic: use a service for receiving location updates and store that info somewhere (e.g. a database). Then in your GUI code have, for example, an `AsyncTask` that checks if there's new info available and updates the GUI accordingly. – J.Nieminen Oct 28 '13 at 21:43
This suggestion is really attractive, and i am sure this will be my next step. Thanks for that. until then, i still want to make working demo without DataBase. Ofcourse, GUI will only get updates when its alive :) – PauliusM Oct 28 '13 at 21:51
For a quick demo you can also use for example the `SharedPreferences` if you don't want to set up a database right away. I'm often storing a lot of different stuff (such as location info) into the prefs by using [Google Gson](https://code.google.com/p/google-gson/) and storing the created json as a string. – J.Nieminen Oct 28 '13 at 21:55
I know, there are a lot of thing to discus and change. My thread is not good, i should request for LocationUpdates and so on, but please stay on topic :) I need to send message to Main thread and update my map with new polyline. – PauliusM Oct 28 '13 at 21:59
Well, I'm otherwise out of ideas (and need to go now). But if you didn't yet, check the link from the third comment about using broadcasts for the communication. Might be a way to go. Otherwise I actually think that you might be faster off doing a simple SharedPreferences-based data sharing instead of hitting the wall with the handlers. Sometimes rewriting a lot is faster than finding a really annoying bug. :) Good luck! – J.Nieminen Oct 28 '13 at 22:08

score 0 · Answer 2 · edited May 23 '17 at 12:10

0

You can not change the UI from without the main thread. If you really want to do it from without use an AsyncTask

Maybe this will help.

edited May 23 '17 at 12:10

Community

1
1

answered Oct 28 '13 at 21:15

Robin Dijkhof

18,665
11
65
116

well, I think that I already implemented something similar to that on your link. And somehow it's not working. I have done this before, but not sure why it's not working this time. – PauliusM Oct 28 '13 at 21:29

score 0 · Accepted Answer · answered Oct 30 '13 at 06:41

Apparently comand mMainHandler.dispatchMessage(msg); executes Handlers handleMessage method on the wrong thread (worker thread). Documantation says that "dispatchMessage(Message msg) Handle system messages here." I have to use sendMessage(Message msg) that "Pushes a message onto the end of the message queue after all pending messages before the current time."

mMap.addPolyline throws illegalstateexception

3 Answers3