How to call setMobileDataEnabled()

Question

i am new to android but i know few thinks but this one is hard for me:

First i want to check if i am connected to the internet: works. then i want to check if the mobile data/wifi i enabled: works. and then i want to turn on the mobile network (if its disabled) to check if i have a (good?) connection to the internet: dont work

I used the code from https://stackoverflow.com/a/8962211/1879409 but i dont know how i can call this methode? I also want to do this in an seperate class file (.java file) and call this function from my main activity.

Can someone give me an example how i can do this??

Thanks for all answers xD

EDIT

Now it looks like this in my Settings.java:

    import java.lang.reflect.Field;
import java.lang.reflect.Method;

import android.content.Context;
import android.net.ConnectivityManager;
import android.util.Log;

public class SettingsHelper {

    static void setMobileDataEnabled(Context context, boolean enabled) {
        try {

            final ConnectivityManager conman = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            final Class conmanClass = Class.forName(conman.getClass().getName());
            final Field iConnectivityManagerField = conmanClass.getDeclaredField("mService");
            iConnectivityManagerField.setAccessible(true);
            final Object iConnectivityManager = iConnectivityManagerField.get(conman);
            final Class iConnectivityManagerClass = Class.forName(iConnectivityManager.getClass().getName());
            final Method setMobileDataEnabledMethod = iConnectivityManagerClass.getDeclaredMethod("setMobileDataEnabled", Boolean.TYPE);
            setMobileDataEnabledMethod.setAccessible(true);

            setMobileDataEnabledMethod.invoke(iConnectivityManager, enabled);
            Log.i("setMobileDataEnabled()","OK");
        } 

        catch (Exception e) 
        {
            e.printStackTrace();
            Log.i("setMobileDataEnabled()","FAIL");
        }         
    }
}

If i call Settings.setMobileDataEnabled(context, true); from my MainActivity i get:

    02-01 14:51:19.680: W/System.err(23318): java.lang.NullPointerException
02-01 14:51:19.700: W/System.err(23318):    at at.htlmbprojekt.wksimonsfeld.iceapp.SettingsHelper.setMobileDataEnabled(SettingsHelper.java:15)
02-01 14:51:19.700: W/System.err(23318):    at at.htlmbprojekt.wksimonsfeld.iceapp.MainActivity.checkIfStorageAvailable(MainActivity.java:83)
02-01 14:51:19.700: W/System.err(23318):    at at.htlmbprojekt.wksimonsfeld.iceapp.MainActivity.access$4(MainActivity.java:81)
02-01 14:51:19.700: W/System.err(23318):    at at.htlmbprojekt.wksimonsfeld.iceapp.MainActivity$2.onClick(MainActivity.java:76)
02-01 14:51:19.700: W/System.err(23318):    at android.view.View.performClick(View.java:4211)
02-01 14:51:19.700: W/System.err(23318):    at android.view.View$PerformClick.run(View.java:17267)
02-01 14:51:19.700: W/System.err(23318):    at android.os.Handler.handleCallback(Handler.java:615)
02-01 14:51:19.700: W/System.err(23318):    at android.os.Handler.dispatchMessage(Handler.java:92)
02-01 14:51:19.700: W/System.err(23318):    at android.os.Looper.loop(Looper.java:137)
02-01 14:51:19.700: W/System.err(23318):    at android.app.ActivityThread.main(ActivityThread.java:4898)
02-01 14:51:19.700: W/System.err(23318):    at java.lang.reflect.Method.invokeNative(Native Method)
02-01 14:51:19.700: W/System.err(23318):    at java.lang.reflect.Method.invoke(Method.java:511)
02-01 14:51:19.700: W/System.err(23318):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
02-01 14:51:19.700: W/System.err(23318):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
02-01 14:51:19.700: W/System.err(23318):    at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:103)
02-01 14:51:19.700: W/System.err(23318):    at dalvik.system.NativeStart.main(Native Method)

Maybe because the context is null? If yes what should i do with he context? If anyone can solve my problem pls send me the WHOLE code and not only some snippets i am a beginner and i dont know what i should do with these snippets xD

Answer 1

First of all, in order to make your code easily readable you can use 'generic' exceptional handler but why using generic exceptional handler isn't a good idea instead of specific exceptions is a different topic about which you can read here: http://www.javaworld.com/javaworld/jw-10-2003/jw-1003-generics.html

Anyway now regarding your actual question, try the code given below, i didn't make change except formatted it to make it more readable and the reason why you are getting NULL exception because you are trying to use an object outside the scope it was instantiated in.

private void setMobileDataEnabled(Context context, boolean enabled) {
    try {

        final ConnectivityManager conman = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        final Class conmanClass = Class.forName(conman.getClass().getName());
        final Field iConnectivityManagerField = conmanClass.getDeclaredField("mService");
        iConnectivityManagerField.setAccessible(true);
        final Object iConnectivityManager = iConnectivityManagerField.get(conman);
        final Class iConnectivityManagerClass = Class.forName(iConnectivityManager.getClass().getName());
        final Method setMobileDataEnabledMethod = iConnectivityManagerClass.getDeclaredMethod("setMobileDataEnabled", Boolean.TYPE);
        setMobileDataEnabledMethod.setAccessible(true);

        setMobileDataEnabledMethod.invoke(iConnectivityManager, enabled);

    } catch (Exception e) {
        e.printStackTrace();
    }         
}

Answer 2

Please check your manifest and make sure permission "CHANGE_NETWORK_STATE" has been added.

Answer 3

If you want to create a class to use your code, do the following:

Create a new class, in the same package of the MainActivity.

Give it any name, for example: MyNetwork.

Write the following:

public class MyNetwork {

    setMobileDataEnabled(Context context, boolean enabled){

        ConnectivityManager conman = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);

        Method setMobileDataEnabledMethod = ConnectivityManager.class.getDeclaredMethod("setMobileDataEnabled", boolean.class);

        setMobileDataEnabledMethod.setAccessible(true);
        setMobileDataEnabledMethod.invoke(conman, enabled);

        }

}

Now just call it from anywhere:

MyNetwork mn;

mn.setMobileDataEnabled(getBaseContext(), true) //or false to disable your data.

You can create any methods inside your class, to call it, just call as:

mn.yourMethod()

Check if you have declared the right permissions in your Manifest.xml.