Check for Active internet connection Android

Question

I am trying to write a part in my app that will differentiate between an Active Wifi connection and an actual connection to the internet. Finding out if there is an active Wifi connection is pretty simple using the connection manager however every time I try to test if I can connect to a website when the Wifi is connected but there is no internet connection I end up in an infinite loop.
I have tried to ping google however this ends up the same way:

Process p1 = java.lang.Runtime.getRuntime().exec("ping -c 1 www.google.com");
int returnVal = 5;
try {
    returnVal = p1.waitFor();
} catch (InterruptedException e) {
    e.printStackTrace();
}
boolean reachable = (returnVal==0);
return reachable;

I also tried this code:

if (InetAddress.getByName("www.xy.com").isReachable(timeout))
{    }
else
{    }

but I could not get isReachable to work.

Answer 1

Here is some modern code that uses an AsynTask to get around an issue where android crashes when you try and connect on the main thread and introduces an alert with a rinse and repeat option for the user.

class TestInternet extends AsyncTask<Void, Void, Boolean> {
    @Override
    protected Boolean doInBackground(Void... params) {
        try {
            URL url = new URL("http://www.google.com");
            HttpURLConnection urlc = (HttpURLConnection) url.openConnection();
            urlc.setConnectTimeout(3000);
            urlc.connect();
            if (urlc.getResponseCode() == 200) {
                return true;
            }
        } catch (MalformedURLException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
            return false;
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return false;
        }
        return false;
    }

    @Override
    protected void onPostExecute(Boolean result) {
        if (!result) { // code if not connected
            AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
            builder.setMessage("An internet connection is required.");
            builder.setCancelable(false);

            builder.setPositiveButton(
                    "TRY AGAIN",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {
                            dialog.cancel();
                            new TestInternet().execute();
                        }
                    });


            AlertDialog alert11 = builder.create();
            alert11.show();
        } else { // code if connected
            doMyStuff();
        }
    }
}

...

new TestInternet().execute();