flutter_bluetooth/example/lib/main.dart

import 'dart:typed_data';

import 'package:flutter/material.dart';
import 'dart:async';

import 'package:flutter/services.dart';
import 'package:flutter_bluetooth/flutter_bluetooth.dart';

void main() => runApp(MyApp());

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  Stream<List<BluetoothDevice>>  _deviceStream;

  @override
  void initState() {
    super.initState();
    _deviceStream = FlutterBluetooth.instance.startScan(filterClasses: [1664 ,7936]);
  }


  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Plugin example app'),
        ),
        body: StreamBuilder<List<BluetoothDevice>>(builder: (context, result){
          return ListView.builder(
            itemCount: result.data.length,
            itemBuilder: (context, index){
              return ListTile(
                  title: Text(result.data[index].name ?? ''),
                  onTap: () async {
                    var socket = await result.data[index].createSocket('00001101-0000-1000-8000-00805F9B34FB');
                    await socket.write(Uint8List.fromList([...'\x1BB'.codeUnits, 5, 9]));
                    await socket.close();
                  },
              );
            },
          );
        }, stream: _deviceStream,),
      ),
    );
  }
}