CODEWITHSUNDEEP
androidandroid-asynctask
Ok-Alex
Ok-Alex

Reputation: 558

Can't stop/restart AsyncTask

Please help. I can restart the AsyncTask. App crashes every time, when second call to updatePoi().

Here is my code:

  1. I'm checking status of task and set cancel(true).

    public void updatePoi() {
    //new RefreshMapTask().execute();
    if (refreshMapTask.getStatus() == AsyncTask.Status.RUNNING || 
        refreshMapTask.getStatus() == AsyncTask.Status.PENDING) {
            refreshMapTask.cancel(true);
        }
        refreshMapTask.execute();
    }
}

  2. Here is my AsyncTask. in doInBackground I wrote a break.

    private class RefreshMapTask extends AsyncTask<Void, Void, Void> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        getMapView().getOverlays().clear();
        myPoiOverlay.clear();
        exitOverlay.clear();
    }


    @Override
    protected Void doInBackground(Void... voids) {
        Application app = (Application)getApplication();
        Log.d(TAG, "exits count = " + app.getExits().size());

        GeoPoint pointToNavigate = null;

        for (Exit exit : app.getExits()) {

            for (Poi poi : exit.getPoi()) {
                if (isCancelled()){
                    break;
                }
                //some code here
            }
        }

        //small code here
        return null;
    }

    @Override
    protected void onPostExecute(Void aVoid) {
        getMapView().invalidate();
    }
}

EDIT: added solution from comments into the question

 public void updatePoi() { 
//new RefreshMapTask().execute(); 
if (refreshMapTask.getStatus() == AsyncTask.Status.RUNNING || 
    refreshMapTask.getStatus() == AsyncTask.Status.PENDING){ 
    refreshMapTask.cancel(true);
    refreshMapTask = new RefreshMapTask();
} else { 
    refreshMapTask = new RefreshMapTask(); 
} 
refreshMapTask.execute(); 
}

Upvotes: 1

Views: 5031

Answers (3)

Jong
Jong

Reputation: 9125

You can't restart a task. Each task object may only be executed once:

The task can be executed only once (an exception will be thrown if a second execution is attempted.)

So create a new object each time you execute it, don't use the same object.

Upvotes: 2

Shakti
Shakti

Reputation: 1581

An AsyncTask instance can only be called once. To make a second call, you need to create a new instance.

Upvotes: 7

Kanaiya Katarmal
Kanaiya Katarmal

Reputation: 6118

try

return null;

final code

@Override
protected Void doInBackground(Void... voids) {
    Application app = (Application)getApplication();
    Log.d(TAG, "exits count = " + app.getExits().size());

    GeoPoint pointToNavigate = null;

    for (Exit exit : app.getExits()) {

        for (Poi poi : exit.getPoi()) {
            if (isCancelled()){
                return null;
            }
            //some code here
        }
    }

    //small code here
    return null;
}

Upvotes: 0

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