Executing in Background

If you want to call the telephony methods in background, you can do in the following ways.

1. Using only Telephony.instance

If you want to continue using Telephony.insatnce in the background, you will need to make sure that once the app comes back to the front, it again calls Telephony.insatnce.

backgrounMessageHandler(SmsMessage message) async {
    // Handle background message
    Telephony.insatnce.sendSms(to: "123456789", message: "Message from background")
}

void main() {
  runApp(MyApp());
}

class _MyAppState extends State<MyApp> {
  String _message;
  // This will not work as the instance will be replaced by
  // the one in background.
  final telephony = Telephony.instance;

   @override
  void initState() {
    super.initState();
    // You should make sure call to instance is made every time 
    // app comes to foreground
    final inbox = Telephony.insatnce.getInboxSms()
  }

2. Use backgroundInstance

If you cannot make sure that the call to instance would be made every time app comes to foreground, or if you would prefer to maintain a separate background instance, you can use Telephony.backgroundInstance in the background execution context.

backgrounMessageHandler(SmsMessage message) async {
    // Handle background message
    Telephony.backgroundInstance.sendSms(to: "123456789", message: "Message from background")
}

void main() {
  runApp(MyApp());
}

class _MyAppState extends State<MyApp> {
  String _message;
  final telephony = Telephony.instance;

   @override
  void initState() {
    super.initState();
    final inbox = telephony.getInboxSms()
  }