Android Kotlin实现每分钟向REST API发送传感器与心率数据

一、解决屏幕熄灭后传感器数据停止的问题 #

Android屏幕熄灭后会进入低功耗模式，后台服务易被系统限制，需做以下调整：

• 使用前台服务（Foreground Service）：前台服务会在通知栏保留持续通知，系统不会轻易终止它。在服务启动时调用startForeground()：

// 先创建通知渠道（Android 8.0+必填）
private fun createNotificationChannel() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        val channel = NotificationChannel(CHANNEL_ID, "数据采集通道", NotificationManager.IMPORTANCE_LOW)
        val manager = getSystemService(NotificationManager::class.java)
        manager.createNotificationChannel(channel)
    }
}

// 在服务onCreate/onStartCommand中启动前台服务
override fun onCreate() {
    super.onCreate()
    createNotificationChannel()
    val notification = NotificationCompat.Builder(this, CHANNEL_ID)
        .setContentTitle("数据采集服务")
        .setContentText("正在采集运动与心率数据")
        .setSmallIcon(R.drawable.ic_notification)
        .build()
    startForeground(NOTIFICATION_ID, notification)
}

• 申请唤醒锁（Wake Lock）：保证屏幕熄灭后CPU仍能运行，记得在不需要时释放避免耗电：

private lateinit var wakeLock: PowerManager.WakeLock

override fun onCreate() {
    super.onCreate()
    val powerManager = getSystemService(POWER_SERVICE) as PowerManager
    wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "MyApp::DataLock")
    wakeLock.acquire(60*1000L /* 可设置超时时间，按需调整 */)
}

override fun onDestroy() {
    super.onDestroy()
    if (wakeLock.isHeld) wakeLock.release()
}

同时在Manifest中添加权限：<uses-permission android:name="android.permission.WAKE_LOCK" />

• Android 12+需额外申请POST_NOTIFICATIONS权限，否则前台服务无法启动。

二、将MeasureClient整合到服务中 #

直接在服务内初始化MeasureClient并管理其生命周期，同步两类数据后定时上报：

1. 服务内初始化MeasureClient：

private lateinit var measureClient: MeasureClient
private var latestHeartRate: Int? = null

override fun onCreate() {
    super.onCreate()
    measureClient = MeasureClient(this)
    // 请求健康数据权限并启动监听
    measureClient.requestPermissions { granted ->
        if (granted) startHeartRateListen()
    }
}

private fun startHeartRateListen() {
    measureClient.registerHeartRateCallback { rate ->
        latestHeartRate = rate
    }
}

2. 同步加速度与心率数据，定时上报：
   在服务中维护最新的加速度数据，用定时器每分钟触发一次API请求：

private var latestAccelData: FloatArray? = null
private val uploadHandler = Handler(Looper.getMainLooper())
private val uploadTask = object : Runnable {
    override fun run() {
        // 两类数据都存在时才上报
        latestAccelData?.let { accel ->
            latestHeartRate?.let { rate ->
                sendCombinedDataToApi(accel, rate)
            }
        }
        uploadHandler.postDelayed(this, 60 * 1000)
    }
}

override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
    uploadHandler.post(uploadTask)
    // 初始化加速度传感器监听
    initAccelerometer()
    return START_STICKY
}

private fun initAccelerometer() {
    val sensorManager = getSystemService(SENSOR_SERVICE) as SensorManager
    val accelSensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER)
    sensorManager.registerListener(this, accelSensor, SensorManager.SENSOR_DELAY_NORMAL)
}

// 实现SensorEventListener的onSensorChanged更新加速度数据
override fun onSensorChanged(event: SensorEvent?) {
    event?.takeIf { it.sensor.type == Sensor.TYPE_ACCELEROMETER }?.let {
        latestAccelData = it.values.clone()
    }
}

3. 销毁服务时清理资源：

override fun onDestroy() {
    super.onDestroy()
    uploadHandler.removeCallbacks(uploadTask)
    val sensorManager = getSystemService(SENSOR_SERVICE) as SensorManager
    sensorManager.unregisterListener(this)
    measureClient.unregisterHeartRateCallback()
}

三、额外注意事项 #

• 确保已申请传感器权限（Android 10+需android.permission.ACTIVITY_RECOGNITION）和对应健康数据权限。
• 前台服务+唤醒锁会增加耗电，建议提供用户开关控制后台采集，或在长时间无操作时自动停止服务。
• 网络不稳定时可将数据缓存到本地（如Room数据库），待网络恢复后批量上传。

内容的提问来源于stack exchange，提问作者Gnagno