How to use any state management for my bluetooth app? - flutter

Question

I am trying to use a connected bluetooth device on other pages, but I'm unable to do that. I tried to use the provider, but that did not work, parameter passing did not work either.
After testing, I am using the following
I made a class ReactiveProvider
class ReactiveProvider(){
Stream<ConnectionStateUpdate> get currentConnectionStream {
return flutterReactiveBle.connectToAdvertisingDevice(
id: _foundBleUARTDevices[index].id,
prescanDuration: const Duration(seconds: 1),
withServices: [_uartUuid, _uartRx, _uartTx],
);
}
}
and setup in start
void main() {
runApp(
MultiProvider(providers: [
StreamProvider<ConnectionStateUpdate>(
create: (context) => ReactiveProvider().currentConnectionStream,
initialData: const ConnectionStateUpdate(
deviceId: "",
connectionState: DeviceConnectionState.disconnected,
failure: null),
)
], child: const MainApp()),
);
}
and in StatefullWidget
final _currentConnectionStream = Provider.of<ConnectionStateUpdate>(context);
I got the errors
The instance member 'context' can't be accessed in an initializer.
Try replacing the reference to the instance member with a different expression
and
The method 'listen' isn't defined for the type 'ConnectionStateUpdate'.
Try correcting the name to the name of an existing method, or defining a method named 'listen'.
In following function
_connection = _currentConnectionStream.listen((event) {});
I want to access the following parameters on another page using any state management
final flutterReactiveBle = FlutterReactiveBle();
List<DiscoveredDevice> _foundBleUARTDevices = [];
late StreamSubscription<DiscoveredDevice> _scanStream;
late Stream<ConnectionStateUpdate> _currentConnectionStream;
late StreamSubscription<ConnectionStateUpdate> _connection;
late QualifiedCharacteristic _txCharacteristic;
//late QualifiedCharacteristic _rxCharacteristic;
late Stream<List<int>> _receivedDataStream;
These are other functions I am using
void onNewReceivedData(List<int> data) {
_numberOfMessagesReceived += 1;
_receivedData
.add("$_numberOfMessagesReceived: ${String.fromCharCodes(data)}");
if (_receivedData.length > 10) {
_receivedData.removeAt(0);
}
}
void _disconnect() async {
await _connection.cancel();
_connected = false;
}
void _stopScan() async {
await _scanStream.cancel();
_scanning = false;
}
void _startScan() async {
_foundBleUARTDevices = [];
_scanning = true;
_scanStream = flutterReactiveBle
.scanForDevices(withServices: [_uartUuid]).listen((device) {
if (_foundBleUARTDevices.every((element) => element.id != device.id)) {
_foundBleUARTDevices.add(device);
}
}, onError: (Object error) {
_logTexts = "${_logTexts}ERROR while scanning:$error \n";
}, onDone: () async {
await _scanStream.cancel();
_scanning = false;
});
}
void onConnectDevice(index) {
_currentConnectionStream = flutterReactiveBle.connectToAdvertisingDevice(
id: _foundBleUARTDevices[index].id,
prescanDuration: const Duration(seconds: 1),
withServices: [_uartUuid, _uartRx, _uartTx],
);
_logTexts = "";
_connection = _currentConnectionStream.listen((event) {
var id = event.deviceId.toString();
switch (event.connectionState) {
case DeviceConnectionState.connecting:
{
_logTexts = "${_logTexts}Connecting to $id\n";
break;
}
case DeviceConnectionState.connected:
{
_connected = true;
_logTexts = "${_logTexts}Connected to $id\n";
_numberOfMessagesReceived = 0;
_receivedData = [];
_txCharacteristic = QualifiedCharacteristic(
serviceId: _uartUuid,
characteristicId: _uartTx,
deviceId: event.deviceId);
_receivedDataStream =
flutterReactiveBle.subscribeToCharacteristic(_txCharacteristic);
_receivedDataStream.listen((data) {
onNewReceivedData(data);
}, onError: (dynamic error) {
_logTexts = "${_logTexts}Error:$error$id\n";
});
break;
}
case DeviceConnectionState.disconnecting:
{
_connected = false;
_logTexts = "${_logTexts}Disconnecting from $id\n";
break;
}
case DeviceConnectionState.disconnected:
{
_logTexts = "${_logTexts}Disconnected from $id\n";
break;
}
}
});
}
Another question I have, is how I can use or keep connected using on void onConnectDevice(index) function, because as per the provider you don't need to pass the parameters.