Flutter蓝牙通信插件flutter_blue_plus_ohos的使用

flutter_blue_plus_ohos 是一个用于在 Flutter 应用中实现蓝牙通信的插件，特别针对 OpenHarmony (OHOS) 平台进行了优化。它基于 flutter_blue_plus 插件，并提供了对 OHOS 平台的额外支持。以下是如何使用 flutter_blue_plus_ohos 插件进行蓝牙通信的基本步骤。

1. 添加依赖

首先，在 pubspec.yaml 文件中添加 flutter_blue_plus_ohos 插件的依赖：

dependencies:
  flutter:
    sdk: flutter
  flutter_blue_plus_ohos: ^1.0.0 # 请根据实际版本号进行替换

然后运行 flutter pub get 来获取依赖。

2. 初始化插件

在你的 Dart 代码中，首先需要初始化 flutter_blue_plus_ohos 插件。

import 'package:flutter_blue_plus_ohos/flutter_blue_plus_ohos.dart';

class BluetoothManager {
  final FlutterBluePlusOhos flutterBlue = FlutterBluePlusOhos.instance;

  Future<void> initBluetooth() async {
    // 检查蓝牙是否可用
    bool isAvailable = await flutterBlue.isAvailable;
    if (!isAvailable) {
      print("Bluetooth is not available on this device.");
      return;
    }

    // 检查蓝牙是否开启
    bool isOn = await flutterBlue.isOn;
    if (!isOn) {
      print("Bluetooth is not on.");
      return;
    }

    print("Bluetooth is ready to use.");
  }
}

3. 扫描设备

你可以使用 flutterBlue.startScan 方法来扫描附近的蓝牙设备。

Future<void> scanDevices() async {
  // 开始扫描
  flutterBlue.startScan(timeout: Duration(seconds: 4));

  // 监听扫描结果
  flutterBlue.scanResults.listen((results) {
    for (ScanResult result in results) {
      print("Found device: ${result.device.name} (${result.device.id})");
    }
  });

  // 停止扫描
  await Future.delayed(Duration(seconds: 4));
  flutterBlue.stopScan();
}

4. 连接设备

扫描到设备后，你可以使用 device.connect 方法来连接设备。

Future<void> connectToDevice(BluetoothDevice device) async {
  // 连接设备
  await device.connect();

  // 监听连接状态
  device.state.listen((state) {
    if (state == BluetoothDeviceState.connected) {
      print("Device connected");
    } else if (state == BluetoothDeviceState.disconnected) {
      print("Device disconnected");
    }
  });
}

5. 发现服务与特征

连接成功后，你可以发现设备提供的服务和特征。

Future<void> discoverServices(BluetoothDevice device) async {
  List<BluetoothService> services = await device.discoverServices();

  for (BluetoothService service in services) {
    print("Service: ${service.uuid}");

    for (BluetoothCharacteristic characteristic in service.characteristics) {
      print("Characteristic: ${characteristic.uuid}");
    }
  }
}

6. 读取和写入特征

你可以使用 characteristic.read 和 characteristic.write 方法来读取和写入特征值。

Future<void> readCharacteristic(BluetoothCharacteristic characteristic) async {
  List<int> value = await characteristic.read();
  print("Characteristic value: $value");
}

Future<void> writeCharacteristic(BluetoothCharacteristic characteristic, List<int> value) async {
  await characteristic.write(value);
  print("Characteristic value written");
}

7. 断开连接

使用 device.disconnect 方法来断开设备连接。

Future<void> disconnectDevice(BluetoothDevice device) async {
  await device.disconnect();
  print("Device disconnected");
}

8. 处理权限

在 OHOS 平台上，使用蓝牙可能需要特定的权限。确保在 AndroidManifest.xml 文件中添加必要的权限：

<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

9. 处理错误

在实际使用中，可能会遇到各种错误，如连接失败、权限问题等。确保在代码中添加适当的错误处理逻辑。

try {
  await connectToDevice(device);
} catch (e) {
  print("Failed to connect to device: $e");
}

10. 完整示例

以下是一个完整的示例，展示了如何使用 flutter_blue_plus_ohos 插件进行蓝牙通信：

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

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

class _BluetoothAppState extends State<BluetoothApp> {
  final FlutterBluePlusOhos flutterBlue = FlutterBluePlusOhos.instance;
  List<BluetoothDevice> devices = [];

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

  Future<void> initBluetooth() async {
    bool isAvailable = await flutterBlue.isAvailable;
    if (!isAvailable) {
      print("Bluetooth is not available on this device.");
      return;
    }

    bool isOn = await flutterBlue.isOn;
    if (!isOn) {
      print("Bluetooth is not on.");
      return;
    }

    print("Bluetooth is ready to use.");
  }

  Future<void> scanDevices() async {
    flutterBlue.startScan(timeout: Duration(seconds: 4));

    flutterBlue.scanResults.listen((results) {
      setState(() {
        devices = results.map((result) => result.device).toList();
      });
    });

    await Future.delayed(Duration(seconds: 4));
    flutterBlue.stopScan();
  }

  Future<void> connectToDevice(BluetoothDevice device) async {
    await device.connect();
    print("Device connected");

    List<BluetoothService> services = await device.discoverServices();
    for (BluetoothService service in services) {
      print("Service: ${service.uuid}");
      for (BluetoothCharacteristic characteristic in service.characteristics) {
        print("Characteristic: ${characteristic.uuid}");
      }
    }
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Bluetooth App"),
      ),
      body: ListView.builder(
        itemCount: devices.length,
        itemBuilder: (context, index) {
          return ListTile(
            title: Text(devices[index].name ?? "Unknown Device"),
            subtitle: Text(devices[index].id.toString()),
            onTap: () => connectToDevice(devices[index]),
          );
        },
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: scanDevices,
        child: Icon(Icons.search),
      ),
    );
  }
}

void main() => runApp(MaterialApp(
  home: BluetoothApp(),
));