ConcurrentModificationException in MapActivity

Question

this is my first question here, so if anything's wrong, do tell.

Now, I have a public class MainMap extends MapActivity which uses a MyLocationListener for the user's location and a HelloItemizedOverlay. I'm getting certain POI's from an XML-file which I want to add markers (pretty basic Overlays).

User presses a button, AsyncTask starts:

private class GetPOITask extends AsyncTask<String, Void, Void> {

 protected Void doInBackground(String... params) {
    clearMapOverlay();
    if(!isBusyAddingOverlays)
    {
       connect(params[0]);
    }
    return null;
 }

 protected void onPreExecute() {
  clearMapOverlay();
 }
}

Clearing out the MapOverlay (this.mv is a MapView):

public void clearMapOverlay()
 {
  this.mv.getOverlays().remove(placesItemizedOverlay);
  this.mv.postInvalidate();
  this.mv.getOverlays().add(myLoc);
 }

This is the method that my connect-method calls when I have enough information to add a marker:

private void addOverlayToList(int id, GeoPoint point, String title, String description)
{
 //Log.e("Debug", "Adding overlay");
 placesItemizedOverlay.addOverlay(new POIOverlay(id, point, title, description));
 this.mv.getOverlays().add(placesItemizedOverlay);
}

That should be all the relevant code.

The problem is that when I add the POI's and zoom the map (or move it), I get a ConcurrentModificationException.

I've searched through this site, reading similar threads (this one for example) but I can't really find what I'm doing wrong.

Knowing myself, it's probably something obvious.

Thanks in advance,

iarwain

score 0 · Answer 1 · answered Feb 12 '11 at 23:05

This could come from the fact that addOverlayToList() is called from connect() which is called in a different Thread (doInBackground()). Only the thread wich initiated the UI can touch its views.

Move the add overlay calls into onPostExecute() (which you should override) of GetPOITask.

ConcurrentModificationException in MapActivity

1 Answers1