Update UI from callback in flutter

I am making telecall app on flutter. Out going Phone calls will be made here. After complete phone call have to submit customer feedback by API. Sumit button will be activate after disconnect the phone call.
I am using flutter_phone_direct_caller for phone and phone_state_background for Phone Call State.

class MyCallPage extends StatefulWidget {
const MyCallPage({super.key});
@override
State<MyCallPage> createState() => _MyCallPageState();
}
class _MyCallPageState extends State<MyCallPage> with WidgetsBindingObserver {
TextEditingController controller = TextEditingController();
bool hasPermission = false;
@override
void initState() {
WidgetsBinding.instance.addObserver(this);
_hasPermission();
controller.text = '';
super.initState();
}
@override
void dispose() {
WidgetsBinding.instance.removeObserver(this);
controller.dispose();
super.dispose();
}
Future<void> _hasPermission() async {
final permission = await PhoneStateBackground.checkPermission();
if (mounted) {
setState(() => hasPermission = permission);
}
}
Future<void> _requestPermission() async {
await PhoneStateBackground.requestPermissions();
_init();
}
Future<void> _stop() async {
await PhoneStateBackground.stopPhoneStateBackground();
}
Future<void> _init() async {
if (hasPermission != true) {
await _hasPermission();
await PhoneStateBackground.initialize(
phoneStateBackgroundCallbackHandler);
_callPhone();
} else {
await PhoneStateBackground.initialize(
phoneStateBackgroundCallbackHandler);
_callPhone();
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Detected Phone Call'),
),
body: SafeArea(
child: Center(
child: Column(
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Padding(
padding: const EdgeInsets.only(
left: 16.0, right: 16.0, top: 8.0, bottom: 8.0),
child: TextField(
controller: controller,
textAlign: TextAlign.center,
),
),
const SizedBox(height: 15.0),
// ---- call button ----
SizedBox(
width: 150,
child: ElevatedButton(
onPressed: () {
_init();
},
child: const Text('Call'))),
const SizedBox(height: 15.0),
// ---- api button ----
ElevatedButton(
onPressed: () {
// ----- here goes api logic ----
},
child: const Text('Submit'))
],
),
),
),
);
}
_callPhone() async {
if (controller.text.trim().isNotEmpty) {
await FlutterPhoneDirectCaller.callNumber(controller.text.trim());
} else {
_stop();
}
}
}class MyCallPage extends StatefulWidget {
const MyCallPage({super.key});
@override
State<MyCallPage> createState() => _MyCallPageState();
}
class _MyCallPageState extends State<MyCallPage> with WidgetsBindingObserver {
TextEditingController controller = TextEditingController();
bool hasPermission = false;
@override
void initState() {
WidgetsBinding.instance.addObserver(this);
_hasPermission();
controller.text = '';
super.initState();
}
@override
void dispose() {
WidgetsBinding.instance.removeObserver(this);
controller.dispose();
super.dispose();
}
Future<void> _hasPermission() async {
final permission = await PhoneStateBackground.checkPermission();
if (mounted) {
setState(() => hasPermission = permission);
}
}
Future<void> _requestPermission() async {
await PhoneStateBackground.requestPermissions();
_init();
}
Future<void> _stop() async {
await PhoneStateBackground.stopPhoneStateBackground();
}
Future<void> _init() async {
if (hasPermission != true) {
await _hasPermission();
await PhoneStateBackground.initialize(
phoneStateBackgroundCallbackHandler);
_callPhone();
} else {
await PhoneStateBackground.initialize(
phoneStateBackgroundCallbackHandler);
_callPhone();
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Detected Phone Call'),
),
body: SafeArea(
child: Center(
child: Column(
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Padding(
padding: const EdgeInsets.only(
left: 16.0, right: 16.0, top: 8.0, bottom: 8.0),
child: TextField(
controller: controller,
textAlign: TextAlign.center,
),
),
const SizedBox(height: 15.0),
// ---- call button ----
SizedBox(
width: 150,
child: ElevatedButton(
onPressed: () {
_init();
},
child: const Text('Call'))),
const SizedBox(height: 15.0),
// ---- api button ----
ElevatedButton(
onPressed: () {
// ----- here goes api logic ----
},
child: const Text('Submit'))
],
),
),
),
);
}
_callPhone() async {
if (controller.text.trim().isNotEmpty) {
await FlutterPhoneDirectCaller.callNumber(controller.text.trim());
} else {
_stop();
}
}
}

call back function is

// Be sure to annotate @pragma('vm:entry-point') your callback function to avoid issues in
// release mode on Flutter >= 3.3.0
@pragma('vm:entry-point')
// Defines a callback that will handle all background incoming events
Future phoneStateBackgroundCallbackHandler(
PhoneStateBackgroundEvent event,
String number,
int duration,
) async {
switch (event) {
case PhoneStateBackgroundEvent.incomingstart:
log('Incoming call start, number: $number, duration: $duration s');
break;
case PhoneStateBackgroundEvent.incomingmissed:
log('Incoming call missed, number: $number, duration: $duration s');
break;
case PhoneStateBackgroundEvent.incomingreceived:
log('Incoming call received, number: $number, duration: $duration s');
break;
case PhoneStateBackgroundEvent.incomingend:
log('Incoming call ended, number: $number, duration $duration s');
break;
case PhoneStateBackgroundEvent.outgoingstart:
log('Outgoing call start, number: $number, duration: $duration s');
break;
case PhoneStateBackgroundEvent.outgoingend:
log('Outgoing call ended, number: $number, duration: $duration s');
break;
}
}

Now I can not enable or disable submit button. try with riverpod, provider also not working here. please help me.

Use Isolated Server and use a listener on it. Register the Isolated Server from init and remove it from dispose. Use call back from your defined function.