android.os.NetworkOnMainThreadException with android 4.2 [duplicate]

Answer 1

This is the correct way:

public class JSONParser extends AsyncTask <String, Void, String>{

    static InputStream is = null;

static JSONObject jObj = null;
static String json = "";

// constructor
public JSONParser() {

}
@Override
protected String doInBackground(String... params) {


    // Making HTTP request
    try {
        // defaultHttpClient
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpGet httpPost = new HttpGet(url);

            HttpResponse getResponse = httpClient.execute(httpPost);
           final int statusCode = getResponse.getStatusLine().getStatusCode();

           if (statusCode != HttpStatus.SC_OK) { 
              Log.w(getClass().getSimpleName(), 
                  "Error " + statusCode + " for URL " + url); 
              return null;
           }

           HttpEntity getResponseEntity = getResponse.getEntity();

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

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        Log.d("IO", e.getMessage().toString());
        e.printStackTrace();

    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;


}
protected void onPostExecute(String page)
{   
    //onPostExecute
}   
}

To call it (from main):

mJSONParser = new JSONParser();
mJSONParser.execute();

Answer 2

Use StrictMode Something like this:-

   if (android.os.Build.VERSION.SDK_INT > 9) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();

        StrictMode.setThreadPolicy(policy); 
        }

Answer 3

Please make sure that you don't do any network access on UI Thread, instead do it in Async Task

The reason why your application crashes on Android versions 3.0 and above, but works fine on Android 2.x is because since HoneyComb are much stricter about abuse against the UI Thread. For example, when an Android device running HoneyComb or above detects a network access on the UI thread, a NetworkOnMainThreadException will be thrown.

See this

Answer 4

Write below code into your MainActivity file after setContentView(R.layout.activity_main);

if (android.os.Build.VERSION.SDK_INT > 9) {
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
    StrictMode.setThreadPolicy(policy);
}

And below import statement into your java file.

import android.os.StrictMode;

Answer 5

android.os.NetworkOnMainThreadException occurs when you try to access network on your main thread (You main activity execution). To avoid this, you must create a separate thread or AsyncTask or Runnable implementation to execute your JSON data loading. Since HoneyComb you can not further execute the network task on main thread. Here is the implementation using AsyncTask for a network task execution