How to fix NetworkonMainThreadException in Android?

zzlalani picture zzlalani · Nov 2, 2013 · Viewed 34.5k times · Source

I'm creating an project for assignment, I'm new to Android, and I wanted to access json from very common url http://api.androidhive.info/contacts/,

Problem: I'm trying to read the url and fetch and parse the json returned by this url,

I've already added following line into my AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET"/>

Preferences: and my android preferences are

<uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />
  1. Api level 18
  2. Android 4.3

and this is how I'm trying to read the url

static InputStream is = null;

DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);

HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();

The Error Message

11-02 05:23:47.843: E/AndroidRuntime(2207): FATAL EXCEPTION: main
11-02 05:23:47.843: E/AndroidRuntime(2207): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.me.countrypedia/com.me.countrypedia.MainActivity}: android.os.NetworkOnMainThreadException
11-02 05:23:47.843: E/AndroidRuntime(2207):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
11-02 05:23:47.843: E/AndroidRuntime(2207):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
11-02 05:23:47.843: E/AndroidRuntime(2207):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
11-02 05:23:47.843: E/AndroidRuntime(2207):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)

Also I'm following this tutorial for ListView Example http://www.androidhive.info/2011/11/android-xml-parsing-tutorial/

Answer

Philipp Jahoda picture Philipp Jahoda · Nov 2, 2013

Your Exception actually tells you exactly what you are doing wrong. You are not using another thread to perform NetworkOperations. Instead, you perform the network operation on your UI-Thread, which cannot (does not) work on Android.

Your code that connects to the url should be executed for example inside an AsyncTasks doInBackground() method, off the UI-Thread.

Take a look at this question on how to use the AsyncTask: How to use AsyncTask