Android NetworkOnMainThreadException when calling Url.OpenStream

Question

I get this exception when running my code on emulator (Android 4.0.3 / API 15). While opening a stream it will throw an exception. Error-message is null.

try {
    String adress        = "xxx";
    URL url              = new URL(adress);
    InputSource source   = new InputSource(url.openStream());

} catch (Exception e) {
    (new TextView).setText("Error: "+e.getMessage());
}

URL is still working with the emulator (in browser).

I have cleaned the project.

Also Internet connection is allowed:

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

Exception : android.os.NetworkOnMainThreadException

Answer 1

Please never run a networking operation on the main (UI) thread .

Main thread is used to:

• interact with user.
• render UI components.

any long operation on it may risk your app to be closed with ANR message.

Take a look at the following :

• Keeping your application Responsive
• NetworkOnMainThreadException

you can easily use an AsyncTask or a Thread to perform your network operations.

Here is a great tutorial about threads and background work in android: Link