flutter_gb_pos_print 是一个用于 Flutter 的票据打印插件，它允许你通过蓝牙连接 POS 打印机并打印小票。这个插件通常用于餐饮、零售等需要打印小票的场景。

1. 添加依赖

首先，你需要在 pubspec.yaml 文件中添加 flutter_gb_pos_print 插件的依赖：

dependencies:
  flutter:
    sdk: flutter
  flutter_gb_pos_print: ^0.0.1  # 请检查最新版本

然后运行 flutter pub get 来获取依赖。

2. 初始化插件

在你的 Flutter 应用中，首先需要初始化插件并扫描可用设备：

import 'package:flutter_gb_pos_print/flutter_gb_pos_print.dart';

void initPrinter() async {
  // 初始化插件
  await FlutterGbPosPrint.init();

  // 扫描可用设备
  List<BluetoothDevice> devices = await FlutterGbPosPrint.scanDevices();
  
  // 打印设备列表
  devices.forEach((device) {
    print('Device: ${device.name}, Address: ${device.address}');
  });
}

3. 连接打印机

选择一个设备并连接：

void connectToPrinter(BluetoothDevice device) async {
  bool isConnected = await FlutterGbPosPrint.connect(device.address);
  
  if (isConnected) {
    print('Connected to ${device.name}');
  } else {
    print('Failed to connect to ${device.name}');
  }
}

4. 打印小票

连接成功后，你可以调用 print 方法来打印小票。通常你需要传递一个包含打印内容的字符串：

void printReceipt() async {
  String receipt = """
  === 餐厅小票 ===
  订单号: 123456
  时间: 2023-10-01 12:00
  -----------------
  商品        数量    价格
  汉堡        1       10.00
  薯条        1       5.00
  -----------------
  总计:       15.00
  === 谢谢惠顾 ===
  """;

  bool isPrinted = await FlutterGbPosPrint.print(receipt);
  
  if (isPrinted) {
    print('Receipt printed successfully');
  } else {
    print('Failed to print receipt');
  }
}

5. 断开连接

打印完成后，你可以断开与打印机的连接：

void disconnectPrinter() async {
  await FlutterGbPosPrint.disconnect();
  print('Disconnected from printer');
}

6. 完整示例

以下是一个完整的示例，展示了如何初始化插件、扫描设备、连接打印机并打印小票：

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

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

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: PrinterScreen(),
    );
  }
}

class PrinterScreen extends StatefulWidget {
  [@override](/user/override)
  _PrinterScreenState createState() => _PrinterScreenState();
}

class _PrinterScreenState extends State<PrinterScreen> {
  List<BluetoothDevice> devices = [];
  BluetoothDevice? selectedDevice;

  [@override](/user/override)
  void initState() {
    super.initState();
    initPrinter();
  }

  void initPrinter() async {
    await FlutterGbPosPrint.init();
    devices = await FlutterGbPosPrint.scanDevices();
    setState(() {});
  }

  void connectToPrinter(BluetoothDevice device) async {
    bool isConnected = await FlutterGbPosPrint.connect(device.address);
    if (isConnected) {
      setState(() {
        selectedDevice = device;
      });
      print('Connected to ${device.name}');
    } else {
      print('Failed to connect to ${device.name}');
    }
  }

  void printReceipt() async {
    String receipt = """
    === 餐厅小票 ===
    订单号: 123456
    时间: 2023-10-01 12:00
    -----------------
    商品        数量    价格
    汉堡        1       10.00
    薯条        1       5.00
    -----------------
    总计:       15.00
    === 谢谢惠顾 ===
    """;

    bool isPrinted = await FlutterGbPosPrint.print(receipt);
    if (isPrinted) {
      print('Receipt printed successfully');
    } else {
      print('Failed to print receipt');
    }
  }

  void disconnectPrinter() async {
    await FlutterGbPosPrint.disconnect();
    setState(() {
      selectedDevice = null;
    });
    print('Disconnected from printer');
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('POS Printer'),
      ),
      body: Column(
        children: [
          Expanded(
            child: ListView.builder(
              itemCount: devices.length,
              itemBuilder: (context, index) {
                return ListTile(
                  title: Text(devices[index].name),
                  subtitle: Text(devices[index].address),
                  onTap: () => connectToPrinter(devices[index]),
                );
              },
            ),
          ),
          if (selectedDevice != null)
            Column(
              children: [
                Text('Connected to: ${selectedDevice!.name}'),
                ElevatedButton(
                  onPressed: printReceipt,
                  child: Text('Print Receipt'),
                ),
                ElevatedButton(
                  onPressed: disconnectPrinter,
                  child: Text('Disconnect'),
                ),
              ],
            ),
        ],
      ),
    );
  }
}