android.os.NetworkOnMainThreadException

Question

I am trying to set a url to my notification's setLargeIcon but while doing this I got the android.os.NetWorkOnMainThreadException error , I saw some posts that mention using AsyncTask, but I do not know how to implement that into my code.

@Override
public void onReceive(final Context context, Intent intent) {
    Log.d(TAG, " START");
    try {
        if (intent == null)
        {
            Log.d(TAG, "Receiver intent null");
        }
        else
        {
                Log.d(TAG,intent.toString());
                String action = intent.getAction();
                Log.d(TAG, "got action " + action );
                String channel = intent.getExtras().getString("com.parse.Channel");
                JSONObject json = new JSONObject(intent.getExtras().getString("com.parse.Data"));

                Log.d(TAG, "got action " + action + " on channel " + channel + " with:");
                Iterator itr = json.keys();
                while (itr.hasNext()) {
                    String key = (String) itr.next();

                    Log.d(TAG, "..."+key+ "=>" +json.getString(key));
                    if (key.equals("customdata"))
                    {
                        Log.d(TAG,"1.0");
                        msg=json.getString(key);    
                        Log.d(TAG,msg.toString());
                    }
                    Log.d(TAG,"1.1");
                    if(key.equals("image_url"))
                    {
                        msg1=json.getString(key);       
                        Log.d("msg1",msg1.toString());
                    }
                }

                Bitmap bitmap = getBitmapFromURL(msg1);


    }           
    } catch (JSONException e) {
        Log.d(TAG, "JSONException: " + e.getMessage());
    }        
}
public Bitmap getBitmapFromURL(String strURL) {
    try {
        URL url = new URL(strURL);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setDoInput(true);
        connection.connect();
        InputStream input = connection.getInputStream();
        Bitmap myBitmap = BitmapFactory.decodeStream(input);
        return myBitmap;
    } catch (IOException e) {
        e.printStackTrace();
        return null;
    }
}

onReceive() method gets execute in main thread and you are loading image in onReceive (). Move your image load logic to Async task — Subham, Nov 10 '14 at 04:14
So in onReceive(), I do this "new RetrieveTask().execute(msg1); "? cause I need to pass the msg1 that contains the url to be converted — Derek Toh, Nov 10 '14 at 04:20
possible duplicate of [android.os.NetworkOnMainThreadException](http://stackoverflow.com/questions/6343166/android-os-networkonmainthreadexception) — Haresh Chhelana, Nov 10 '14 at 04:35
@DerekToh "new RetrieveTask().execute(msg1); this will be a correct approach — Subham, Nov 10 '14 at 05:04

score 2 · Answer 1 · answered Nov 10 '14 at 04:28

you can use AsyncTask as:

class LoadBitmaps extends AsyncTask<String, Void, Void> {


    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();
        // do something  // show some progress of loading images
    }

    @Override
    protected Void doInBackground(String... str) {

        try {
            URL url = new URL(str[0]);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setDoInput(true);
            connection.connect();
            InputStream input = connection.getInputStream();
            Bitmap myBitmap = BitmapFactory.decodeStream(input);

        } catch (IOException e) {
            e.printStackTrace();

        }
        return null;
    }


    @Override
    protected void onPostExecute(Void v) {
        // do something
    }


}

score 0 · Answer 2 · edited May 23 '17 at 12:19

This exception occurred because you getting the data from network in the main thread. Move it to AsyncTask's onBackground or a Thread so the process of getting data will be on background thread. Example (using a Thread) :

Thread thread = new Thread(new Runnable(){
    @Override
    public void run() {
        try {
            getBitmapFromURL(url);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
});

thread.start();

Take a look here if you are not sure whether to use Thread or AsyncTask :

Asynctask vs Thread in android

android.os.NetworkOnMainThreadException

2 Answers2