flutter 蓝牙打印

Flutter提供了bluetooth_serial插件来进行蓝牙打印，以下是一些简单的示例代码：

1. 导入bluetooth_serial插件

import 'package:flutter_bluetooth_serial/flutter_bluetooth_serial.dart';

2. 初始化蓝牙连接

BluetoothConnection connection;
BluetoothDevice selectedDevice;
bool get isConnected => connection != null && connection.isConnected;
bool get isDisconnecting => _isDisconnecting;

Future<void> _connect() async {
  if (selectedDevice == null) {
    throw Exception("No device selected");
  }

  BluetoothConnection.toAddress(selectedDevice.address).then((_connection) {
    print('Connected to the device');
    connection = _connection;
    setState(() {
      _connected = true;
    });

    connection.input.listen((data) {
      print('Data incoming: ${ascii.decode(data)}');
    }).onDone(() {
      // 连接已关闭
      print('Disconnected by remote request');
      setState(() {
        _connected = false;
        connection = null;
      });
    });
  }).catchError((error) {
    print('Cannot connect, exception occurred');
    print(error);
  });
}

3. 发送打印指令

void _sendDataToBluetooth(String data) async {
  connection.output.add(utf8.encode(data + "\r\n"));
  await connection.output.allSent;
  print("Data sent $data");
}

4. 关闭连接

void _disconnect() async {
  _isDisconnecting = true;
  await connection.close();
  setState(() {
    _connected = false;
    connection = null;
  });
  _isDisconnecting = false;
}

以上是一个简单的蓝牙打印示例代码，你可以根据自己的需求进行修改和扩展。