Flutter 插件esense_flutter的使用_eSense Flutter插件支持在Android和iOS平台上使用eSense耳戴式计算平台

eSense Flutter插件支持在Android和iOS平台上使用eSense耳戴式计算平台。本文将详细介绍如何安装、配置以及使用这个插件。

安装 (Flutter)

首先，在pubspec.yaml文件中添加esense_flutter作为依赖项：

dependencies:
  esense_flutter: ^latest_version

运行以下命令来获取包：

flutter pub get

Android 配置

由于插件使用蓝牙从eSense耳塞获取数据，因此需要启用访问蓝牙的权限。在AndroidManifest.xml文件中添加以下权限：

<uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" android:maxSdkVersion="30" />
<uses-permission android:name="android.permission.BLUETOOTH_SCAN" android:usesPermissionFlags="neverForLocation" />
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT"/>

还需要确保在应用中获得使用蓝牙的权限。可以参考示例应用了解如何使用permission_handler进行权限处理。

设置android/app/build.gradle文件中的编译和最低SDK版本分别为28和23。

iOS 配置

要求iOS 10或更高版本。确保在ios/Runner目录下的Info.plist文件中添加以下权限：

<key>NSBluetoothAlwaysUsageDescription</key>
<string>Uses bluetooth to connect to the eSense device</string>
<key>UIBackgroundModes</key>
  <array>
    <string>bluetooth-central</string>
    <string>bluetooth-peripheral</string>
    <string>audio</string>
    <string>external-accessory</string>
    <string>fetch</string>
  </array>

同时，确保Podfile中平台设置为10.0：

platform :ios, '10.0'

使用方法

设置并连接到eSense设备

所有与eSense设备的操作都是通过ESenseManager完成的。创建ESenseManager时，指定设备名称（通常形式为eSense-xxxx）：

import 'package:esense_flutter/esense.dart';

// 创建一个ESenseManager实例
ESenseManager eSenseManager = ESenseManager('eSense-0332');

// 先监听连接事件再尝试连接
eSenseManager.connectionEvents.listen((event) {
  print('CONNECTION event: $event');
});

// 尝试连接到eSense设备
bool connecting = await eSenseManager.connect();

监听传感器事件

可以通过ESenseManager.sensorEvents流访问SensorEvent事件。采样率可以在不监听时设置：

StreamSubscription subscription = eSenseManager.sensorEvents.listen((event) {
  print('SENSOR event: $event');
});

读取eSense设备事件

读取eSense设备属性是异步操作。需要两步：监听ESenseManager.eSenseEvents流，并调用读取操作：

// 设置事件监听器
eSenseManager.eSenseEvents.listen((event) {
  print('ESENSE event: $event');
});

// 调用读取操作
eSenseManager.getDeviceName();

修改eSense设备配置

可以使用ESenseManager的方法更改eSense设备的配置，例如更改设备名称、广告和连接间隔等。注意，setSensorConfig()方法目前尚未实现。

示例Demo

以下是完整的示例代码，展示了如何使用esense_flutter插件：

import 'dart:io';
import 'package:flutter/material.dart';
import 'dart:async';
import 'package:esense_flutter/esense.dart';
import 'package:permission_handler/permission_handler.dart';

void main() => runApp(const MyApp());

class MyApp extends StatefulWidget {
  const MyApp({Key? key}) : super(key: key);

  [@override](/user/override)
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String _deviceName = 'Unknown';
  double _voltage = -1;
  String _deviceStatus = '';
  bool sampling = false;
  String _event = '';
  String _button = 'not pressed';
  bool connected = false;

  static const String eSenseDeviceName = 'eSense-0332';
  ESenseManager eSenseManager = ESenseManager(eSenseDeviceName);

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

  Future<void> _askForPermissions() async {
    if (!(await Permission.bluetoothScan.request().isGranted &&
        await Permission.bluetoothConnect.request().isGranted)) {
      print('WARNING - no permission to use Bluetooth granted.');
    }
    if (Platform.isAndroid) {
      if (!(await Permission.locationWhenInUse.request().isGranted)) {
        print('WARNING - no permission to access location granted.');
      }
    }
  }

  Future<void> _listenToESense() async {
    await _askForPermissions();

    eSenseManager.connectionEvents.listen((event) {
      print('CONNECTION event: $event');

      if (event.type == ConnectionType.connected) _listenToESenseEvents();

      setState(() {
        connected = false;
        switch (event.type) {
          case ConnectionType.connected:
            _deviceStatus = 'connected';
            connected = true;
            break;
          case ConnectionType.unknown:
            _deviceStatus = 'unknown';
            break;
          case ConnectionType.disconnected:
            _deviceStatus = 'disconnected';
            sampling = false;
            break;
          case ConnectionType.device_found:
            _deviceStatus = 'device_found';
            break;
          case ConnectionType.device_not_found:
            _deviceStatus = 'device_not_found';
            break;
        }
      });
    });
  }

  Future<void> _connectToESense() async {
    if (!connected) {
      print('Trying to connect to eSense device...');
      connected = await eSenseManager.connect();

      setState(() {
        _deviceStatus = connected ? 'connecting...' : 'connection failed';
      });
    }
  }

  void _listenToESenseEvents() async {
    eSenseManager.eSenseEvents.listen((event) {
      print('ESENSE event: $event');

      setState(() {
        switch (event.runtimeType) {
          case DeviceNameRead:
            _deviceName = (event as DeviceNameRead).deviceName ?? 'Unknown';
            break;
          case BatteryRead:
            _voltage = (event as BatteryRead).voltage ?? -1;
            break;
          case ButtonEventChanged:
            _button = (event as ButtonEventChanged).pressed ? 'pressed' : 'not pressed';
            break;
        }
      });
    });

    _getESenseProperties();
  }

  void _getESenseProperties() async {
    Timer.periodic(Duration(seconds: 10), (timer) async =>
        (connected) ? await eSenseManager.getBatteryVoltage() : null);

    Timer(Duration(seconds: 2), () async => await eSenseManager.getDeviceName());
    Timer(Duration(seconds: 3), () async => await eSenseManager.getAccelerometerOffset());
    Timer(Duration(seconds: 4), () async => await eSenseManager.getAdvertisementAndConnectionInterval());
    Timer(Duration(seconds: 5), () async => await eSenseManager.getSensorConfig());
  }

  StreamSubscription? subscription;
  void _startListenToSensorEvents() async {
    subscription = eSenseManager.sensorEvents.listen((event) {
      print('SENSOR event: $event');
      setState(() {
        _event = event.toString();
      });
    });
    setState(() {
      sampling = true;
    });
  }

  void _pauseListenToSensorEvents() async {
    subscription?.cancel();
    setState(() {
      sampling = false;
    });
  }

  [@override](/user/override)
  void dispose() {
    _pauseListenToSensorEvents();
    eSenseManager.disconnect();
    super.dispose();
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: const Text('eSense Demo App')),
        body: Align(
          alignment: Alignment.topLeft,
          child: ListView(
            children: [
              Text('eSense Device Status: \t$_deviceStatus'),
              Text('eSense Device Name: \t$_deviceName'),
              Text('eSense Battery Level: \t$_voltage'),
              Text('eSense Button Event: \t$_button'),
              Text(_event),
              Container(
                height: 80,
                width: 200,
                decoration: BoxDecoration(borderRadius: BorderRadius.circular(10)),
                child: TextButton.icon(
                  onPressed: _connectToESense,
                  icon: const Icon(Icons.login),
                  label: const Text('CONNECT....', style: TextStyle(fontSize: 35)),
                ),
              ),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: (!eSenseManager.connected) ? null : (!sampling) ? _startListenToSensorEvents : _pauseListenToSensorEvents,
          tooltip: 'Listen to eSense sensors',
          child: (!sampling) ? const Icon(Icons.play_arrow) : const Icon(Icons.pause),
        ),
      ),
    );
  }
}