Flutter低功耗蓝牙通信插件bluetooth_low_energy_android的使用

当然，以下是一个使用 bluetooth_low_energy_android 插件在 Flutter 中进行低功耗蓝牙通信的示例代码。这个示例将展示如何扫描设备、连接到设备、发现服务和特征值，以及读写特征值。

首先，确保你已经在 pubspec.yaml 文件中添加了 bluetooth_low_energy_android 依赖：

dependencies:
  flutter:
    sdk: flutter
  bluetooth_low_energy_android: ^x.y.z  # 请替换为最新版本号

然后，运行 flutter pub get 来获取依赖。

接下来是示例代码：

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

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

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

class _MyAppState extends State<MyApp> {
  BluetoothLowEnergyManager? _bluetoothManager;
  List<BluetoothDevice> _devices = [];
  BluetoothDevice? _connectedDevice;
  BluetoothService? _service;
  BluetoothCharacteristic? _characteristic;

  @override
  void initState() {
    super.initState();
    initBluetooth();
  }

  Future<void> initBluetooth() async {
    _bluetoothManager = BluetoothLowEnergyManager.instance;

    // 请求权限
    if (!await _bluetoothManager!.isLocationPermissionGranted()) {
      await _bluetoothManager!.requestLocationPermission();
    }

    // 检查蓝牙是否开启
    if (!await _bluetoothManager!.isBluetoothEnabled()) {
      await _bluetoothManager!.enableBluetooth();
    }

    // 开始扫描设备
    _bluetoothManager!.scanForDevices().listen((List<BluetoothDevice> devices) {
      setState(() {
        _devices = devices;
      });
    });
  }

  Future<void> connectToDevice(BluetoothDevice device) async {
    _connectedDevice = device;
    await _bluetoothManager!.connectToDevice(device.address);
    discoverServices();
  }

  Future<void> discoverServices() async {
    if (_connectedDevice == null) return;

    List<BluetoothService> services = await _bluetoothManager!.discoverServices(_connectedDevice!.address);
    setState(() {
      _service = services.firstWhere((service) => service.uuid == "your-service-uuid", orElse: () => null);
    });

    if (_service != null) {
      discoverCharacteristics();
    }
  }

  Future<void> discoverCharacteristics() async {
    if (_service == null) return;

    List<BluetoothCharacteristic> characteristics = await _bluetoothManager!.discoverCharacteristics(_service!.uuid);
    setState(() {
      _characteristic = characteristics.firstWhere((characteristic) => characteristic.uuid == "your-characteristic-uuid", orElse: () => null);
    });
  }

  Future<void> readCharacteristic() async {
    if (_characteristic == null) return;

    List<int> value = await _bluetoothManager!.readCharacteristic(_characteristic!.uuid);
    print("Characteristic value: ${String.fromCharCodes(value)}");
  }

  Future<void> writeCharacteristic(String data) async {
    if (_characteristic == null) return;

    List<int> value = data.codeUnits;
    await _bluetoothManager!.writeCharacteristic(_characteristic!.uuid, value);
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Bluetooth Low Energy Example'),
        ),
        body: Column(
          children: [
            Expanded(
              child: ListView.builder(
                itemCount: _devices.length,
                itemBuilder: (context, index) {
                  return ListTile(
                    title: Text(_devices[index].name ?? "Unknown Device"),
                    onTap: () => connectToDevice(_devices[index]),
                  );
                },
              ),
            ),
            ElevatedButton(
              onPressed: _connectedDevice != null ? readCharacteristic : null,
              child: Text('Read Characteristic'),
            ),
            ElevatedButton(
              onPressed: () {
                writeCharacteristic("Hello BLE");
              },
              child: Text('Write Characteristic'),
            ),
          ],
        ),
      ),
    );
  }
}

注意事项：

1. UUID：在 discoverServices 和 discoverCharacteristics 方法中，你需要替换 "your-service-uuid" 和 "your-characteristic-uuid" 为实际的服务和特征值的 UUID。
2. 权限：确保在 AndroidManifest.xml 中添加了必要的蓝牙权限。
3. 错误处理：示例代码省略了错误处理逻辑，实际使用中应添加适当的错误处理。
4. 依赖版本：确保使用最新版本的 bluetooth_low_energy_android 插件，并根据其文档进行调整。

这个示例展示了基本的蓝牙低功耗通信流程，包括扫描设备、连接设备、发现服务和特征值，以及读写特征值。根据实际需求，你可以进一步扩展和修改这个示例。