Nullpointerexception detected with AsyncTask

Question

I am developing an app that downloads an XML file, parses it and then displays the information on the screen. I get a NullPointerException Exception error in the following code:

here is the code:

private class DownloadXmlTask extends AsyncTask<String, Void, List<vehicleInfo>> {
    @Override
    protected List<vehicleInfo> doInBackground(String... url) {
        try {
            return getvehicles.processBusTime();
        } catch (IOException e) {
           return null;
        } catch (XmlPullParserException e) {
            return null;
        }
    }

    @Override
    protected void onPostExecute(List<vehicleInfo> result) {


            for (int record = 0; record < result.size(); record++) {

            double latitude = result.get(record).latitude;
            double longitude = result.get(record).longitude;

                mMap.addMarker(new MarkerOptions().position(new LatLng(latitude,     longitude)).title("Marker"));

        }

    }
}

it is returns a NullPointerException at the line: for (int record = 0; record < result.size(); record++) {

what could be the issue?

thanks.

any of the 2 exceptions caught. you'd know if you logged them. — njzk2, Jan 08 '15 at 20:54

score 0 · Answer 1 · answered Jan 08 '15 at 20:55

0

result is null. Are you sure that getvehicles.processBusTime() is returning a list?

answered Jan 08 '15 at 20:55

weiyin

6,819
4
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You are right. I think it is returning null. – Helix Jan 08 '15 at 21:06
Some jerk voted you down for being nice and answering a duplicate post with a correct answer! I'm voting you back up. – Jacob Brewer Jan 19 '15 at 22:32

score -1 · Answer 2 · answered Jan 08 '15 at 20:56

-1

I would bet money that result is null.

if null is an acceptable value try something like:

 for (int record = 0; result != null && record < result.size(); record++)

answered Jan 08 '15 at 20:56

Jacob Brewer

2,574
1
22
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I think getvehicles.processBusTime() is returning a null list object. – Helix Jan 08 '15 at 21:03

Nullpointerexception detected with AsyncTask

2 Answers2