NetworkHelper.java

private static boolean hasNetwork(Context context) {
  ConnectivityManager connectivityManager = (ConnectivityManager)
    context.getSystemService(Context.CONNECTIVITY_SERVICE);
  NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
  return activeNetworkInfo != null;
}

public static boolean canAccessInternet(Context context) {
  if (hasNetwork(context)) {
    try {
      HttpURLConnection conn = (HttpURLConnection)
              (new URL("http://clients3.google.com/generate_204").openConnection());
      conn.setRequestProperty("User-Agent", "Android");
      conn.setRequestProperty("Connection", "close");
      conn.setConnectTimeout(1500);
      conn.connect();
      return (conn.getResponseCode() == 204 && conn.getContentLength() == 0);
    } catch (IOException e) {
      Log.e(TAG, "Error while checking internet access", e);
    }
  } else {
    Log.d(TAG, "Network not available");
  }
  return false;
}