Android : Caused by: android.os.NetworkOnMainThreadException [duplicate]

Question

String response = getResultForRequest(url);

Where 'url' is JSON formatted which return bunch of data using http GET method.

public static String getResultForRequest(String urlString)
        throws IOException {
    URL url = new URL(urlString);
    HttpURLConnection urlConnection = (HttpURLConnection) url
            .openConnection();
    urlConnection.setRequestMethod("GET");
    urlConnection.setDoInput(true);
    urlConnection.setDoOutput(true);
    urlConnection.connect();

    InputStream is = urlConnection.getInputStream();
    if (is == null)
        return null;
    StringBuffer sb = new StringBuffer();
    BufferedReader br = new BufferedReader(new InputStreamReader(is));
    String line = null;
    try {
        while ((line = br.readLine()) != null)
            sb.append(line);
    } finally {
        br.close();
        is.close();
    }

    return sb.toString();
}

I can not fetch JSON formatted data from 'url' which i have passed in getResultForRequest(url) method.I got an error in urlConnection.connect();. Internet Permission is also given in AndroidManifest.xml file.

Here is my Log.

10-09 13:27:35.264: E/AndroidRuntime(9984): FATAL EXCEPTION: main
10-09 13:27:35.264: E/AndroidRuntime(9984): java.lang.RuntimeException: Unable to start activity ComponentInfo{}: android.os.NetworkOnMainThreadException
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.app.ActivityThread.access$600(ActivityThread.java:140)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.os.Looper.loop(Looper.java:137)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.app.ActivityThread.main(ActivityThread.java:4898)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at java.lang.reflect.Method.invokeNative(Native Method)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at java.lang.reflect.Method.invoke(Method.java:511)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at dalvik.system.NativeStart.main(Native Method)
10-09 13:27:35.264: E/AndroidRuntime(9984): Caused by: android.os.NetworkOnMainThreadException
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1118)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at java.net.InetAddress.getAllByName(InetAddress.java:214)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:315)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpsURLConnectionImpl$HttpsEngine.makeSslConnection(HttpsURLConnectionImpl.java:461)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpsURLConnectionImpl$HttpsEngine.connect(HttpsURLConnectionImpl.java:433)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:289)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:239)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:80)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at libcore.net.http.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:165)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at com.csoft.foursquare.FoursquareService.getResultForRequest(Service.java:564)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at com.csoft.foursquare.FoursquareService.getUserDetails(Service.java:376)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at com.csoft.checkin.CheckinHistoryActivity.onCreate(HistoryActivity.java:52)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.app.Activity.performCreate(Activity.java:5206)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
10-09 13:27:35.264: E/AndroidRuntime(9984):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064)
10-09 13:27:35.264: E/AndroidRuntime(9984):     ... 11 more

Thanks in Advance.

Grape

Please close this question, it has been asked and answered a zillion times – Galitea

To download JSON you can use "Volley" which will do the work for you kpbird.com/2013/05/volley-easy-fast-networking-for-android.html – Roseboro

Answer 1

Add this in your onCreate():

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);

Use the above as a temporary solution. Otherwise use thread or asynctask.

Orientalism

Please, avoid the code above.. at docs you will see: "it's heavily discouraged" about the StrictMode... seems that you are doing some network request on the main thread, you just need to move the request or the respose.getEntity to an AsyncTask, this is the right solution to your problem.. – Mckamey

I said that already in the answer. Only to use the given code as temporary solution, otherwise to use thread/asynctask. – Orientalism

Thanks you save my time. – Cramp

Answer 2

You're attempting to make a network connection on the main (UI) thread. This is not allowed in Android since it will halt the entire UI until you get a response from the server.

Try using AsyncTask, or performing the connection on a separate thread.

Hope this helps.

Arapaima