You could use a BroadcastReceiver:
private class ConnectionMonitor extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (!action.equals(ConnectivityManager.CONNECTIVITY_ACTION))
return;
boolean noConnectivity = intent.getBooleanExtra(
ConnectivityManager.EXTRA_NO_CONNECTIVITY, false);
NetworkInfo aNetworkInfo = (NetworkInfo) intent
.getParcelableExtra(ConnectivityManager.EXTRA_NETWORK_INFO);
if (!noConnectivity) {
if ((aNetworkInfo.getType() == ConnectivityManager.TYPE_MOBILE)
|| (aNetworkInfo.getType() == ConnectivityManager.TYPE_WIFI)) {
// start your service stuff here
}
} else {
if ((aNetworkInfo.getType() == ConnectivityManager.TYPE_MOBILE)
|| (aNetworkInfo.getType() == ConnectivityManager.TYPE_WIFI)) {
// stop your service stuff here
}
}
}
}
Then, you instantiate somewhere in your code:
ConnectionMonitor connectionMonitor = new ConnectionMonitor();
registerReceiver(connectionMonitor, intentFilter);
Note: this code comes from Detect 3G or Wifi Network restoration