Error StrictMode$AndroidBlockGuardPolicy.onNetwork
AndroidJsonAndroid Problem Overview
I created android application and use JSON
get data from server but I got the error show below:
android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
how can I fix this problem
Thank you
Android Solutions
Solution 1 - Android
you have to insert 2 lines "StrictMode" on MainActivity Class, example's below:
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
try {
// JSON here
} catch (JSONException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
setContentView(R.layout.activity_main);
Intent intent=new Intent(this,HomeActivity.class);
startActivity(intent);
}
}
Aey.Sakon
Edit: This answer "solves" the "problem", but it does not really explain it, which is the important part.
Modifying StrictMode is NOT a fix. As well as this exception is not really an error in program logic. It is and error in program paradigm and the exception tells you, that
you should not be performing http calls on your main thread as it leads to UI freezing. As some other answers suggests, you should hand off the http call to AsyncTask class.
https://developer.android.com/reference/android/os/AsyncTask
Changing the StrictMode really just tells the app - do not remind me of me writing bad code. It can work for debugging or in some cases where you know what you are doing but generally it is not the way to go.
Solution 2 - Android
Better to use AsyncTask
as mentioned here, an Alternative for just getting rid of the Exception
is use :
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
or this :
Thread thread = new Thread(new Runnable(){
@Override
public void run() {
try {
//Your code goes here
} catch (Exception e) {
Log.e(TAG, e.getMessage());
}
}
});
thread.start();
in your Activity where Exception
occurs.
Solution 3 - Android
Just add two lines after on create method
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);