bluetooth_print_plus 2.4.0

bluetooth_print_plus is a flutter plugin for bluetooth thermal printer, support Android & iOS, supports tspl/tsc、cpcl、esc pos.

example/lib/main.dart

import 'dart:io';

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

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

import 'function_page.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  const HomePage({super.key});

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> with WidgetsBindingObserver {
  final _bluetoothPrintPlus = BluetoothPrintPlus.instance;
  BluetoothDevice? _device;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) => initBluetooth());
  }

  Future<void> initBluetooth() async {
    /// listen isScanning
    _bluetoothPrintPlus.isScanning.listen((event) {
      print('********** isScanning: $event **********');
      if (mounted) {
        setState(() {});
      }
    });

    /// listen blue state
    _bluetoothPrintPlus.blueState.listen((event) {
      print('********** blueState change: $event **********');
      if (mounted) {
        setState(() {});
      }
    });

    /// listen connect state
    _bluetoothPrintPlus.connectState.listen((event) {
      print('********** connectState change: $event **********');
      switch (event) {
        case ConnectState.connected:
          setState(() {
            if (_device == null) return;
            Navigator.push(
                context,
                MaterialPageRoute(
                    builder: (context) => FunctionPage(_device!)));
          });
          break;
        case ConnectState.disconnected:
          setState(() {
            _device = null;
          });
          break;
      }
    });

    /// listen received data
    _bluetoothPrintPlus.receivedData.listen((data) {
      print('********** received data: $data **********');

      /// do something...
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('BluetoothPrintPlus'),
      ),
      body: SafeArea(
        child: _bluetoothPrintPlus.isBlueOn
            ? Column(
                children: [
                  Expanded(
                      child: StreamBuilder<List<BluetoothDevice>>(
                    stream: _bluetoothPrintPlus.scanResults,
                    initialData: const [],
                    builder: (c, snapshot) => ListView(
                      children: snapshot.data!
                          .map((device) => Container(
                                padding: EdgeInsets.only(
                                    left: 10, right: 10, bottom: 5),
                                child: Row(
                                  mainAxisAlignment:
                                      MainAxisAlignment.spaceBetween,
                                  children: [
                                    Expanded(
                                        child: Column(
                                      crossAxisAlignment:
                                          CrossAxisAlignment.start,
                                      children: [
                                        Text(device.name),
                                        Text(
                                          device.address,
                                          overflow: TextOverflow.ellipsis,
                                          style: TextStyle(
                                              fontSize: 12, color: Colors.grey),
                                        ),
                                        Divider(),
                                      ],
                                    )),
                                    SizedBox(
                                      width: 10,
                                    ),
                                    OutlinedButton(
                                      onPressed: () async {
                                        _device = device;
                                        await _bluetoothPrintPlus
                                            .connect(device);
                                      },
                                      child: const Text("connect"),
                                    )
                                  ],
                                ),
                              ))
                          .toList(),
                    ),
                  )),
                ],
              )
            : Center(
                child: Text(
                  "Bluetooth is turned off\nPlease turn on Bluetooth...",
                  style: TextStyle(
                      fontWeight: FontWeight.w700,
                      fontSize: 16,
                      color: Colors.red),
                  textAlign: TextAlign.center,
                ),
              ),
      ),
      floatingActionButton:
          _bluetoothPrintPlus.isBlueOn ? buildScanButton(context) : null,
    );
  }

  Widget buildScanButton(BuildContext context) {
    if (_bluetoothPrintPlus.isScanningNow) {
      return FloatingActionButton(
        onPressed: onStopPressed,
        backgroundColor: Colors.red,
        child: Icon(Icons.stop),
      );
    } else {
      return FloatingActionButton(
          onPressed: onScanPressed,
          backgroundColor: Colors.green,
          child: Text("SCAN"));
    }
  }

  Future onScanPressed() async {
    try {
      await _bluetoothPrintPlus.startScan(timeout: Duration(seconds: 10));
    } catch (e) {
      print("onScanPressed error: $e");
    }
  }

  Future onStopPressed() async {
    try {
      _bluetoothPrintPlus.stopScan();
    } catch (e) {
      print("onStopPressed error: $e");
    }
  }
}