屏幕关闭后如何运行位置跟踪服务？

Question

屏幕关闭时无法更新位置。

屏幕关闭后如何运行位置跟踪服务？

开启服务

val serviceClass = ControlLocationService::class.java
val intent = Intent(activity, serviceClass)
activity?.startService(intent)

在onLocationChanged方法中，我尝试Log. e（），但在屏幕关闭时不在logcat中显示纬度和经度

class ControlLocationService : Service() {

    lateinit var locationRequest: LocationRequest
    lateinit var fusedLocationProviderClient: FusedLocationProviderClient
    private lateinit var locationCallback:LocationCallback

    override fun onBind(intent: Intent): IBinder? {
        throw UnsupportedOperationException("Not yet implemented")
    }

    @SuppressLint("InvalidWakeLockTag")
    override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int {
        //service is started
        updateLocation()
        return START_STICKY
    }

    @SuppressLint("MissingPermission")
    private fun updateLocation() {
        locationCallback = object : LocationCallback() {
            override fun onLocationResult(locationResult: LocationResult?) {
                onLocationChanged(locationResult!!.lastLocation)
            }
        }
        buildLocationRequest()
        fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this)
        fusedLocationProviderClient.requestLocationUpdates(locationRequest, locationCallback, Looper.myLooper())
    }

    private fun onLocationChanged(location: Location) {
        Log.e("...", location.latitude.toString()+location.longitude.toString())
    }

    private fun buildLocationRequest() {
        locationRequest = LocationRequest()
        locationRequest.priority = LocationRequest.PRIORITY_HIGH_ACCURACY
        locationRequest.interval = 3000
        locationRequest.fastestInterval = 1000
        //locationRequest.smallestDisplacement = 1f
    }


}

屏幕关闭时帮我介绍一下服务管理。谢谢你。

Answer 1

你需要一个wakelock，我还会让你的服务成为前台。这将使android不太可能杀死你的应用程序或服务。实际上，根据后台位置限制，它并没有说你需要一个wakelock——只有前台服务。通过让你的应用程序在后台持续工作，你会让它很快耗尽你的用户电池——这很糟糕。考虑使用被动位置更新，这些可能会在一小时内发生——这可能不是你想要的。

您可能还想了解“打瞌睡”模式，该模式使所有未列入白名单的应用程序在屏幕关闭模式下忽略唤醒锁。

要添加唤醒锁：

val mgr = service.getSystemService(Context.POWER_SERVICE) as PowerManager
val wakeLock = mgr.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "myAppName:MyWakeLock")
wakeLock.acquire()

在onDestroy中：

wakeLock.release()

使用下面的代码将通知添加到通知栏并使服务成为前台。您应该在您的onStartCommand中添加addServiceNotify（this）。

fun addServiceNotification(service: Service) {
    val mgr = NotificationManagerCompat.from(service)
    val title = "Caption"
    val text = "Location"

    if (Build.VERSION.SDK_INT >= 26) {
        val notificationManager = service.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
        if (notificationManager != null) {
            var mChannel: NotificationChannel? = notificationManager.getNotificationChannel(NOTIFICATION_CHANNEL_ID)
            if (mChannel == null) {
                mChannel = NotificationChannel(NOTIFICATION_CHANNEL_ID, "myAppName", NotificationManager.IMPORTANCE_LOW)
                notificationManager.createNotificationChannel(mChannel)
            }
        }

        val notification = NotificationCompat.Builder(service, NOTIFICATION_CHANNEL_ID)
                .setSmallIcon(R.drawable.app_icon)
                .setTicker(title)
                .setWhen(System.currentTimeMillis())
                .setContentTitle(title)
                .setContentText(text)
                .setOnlyAlertOnce(true)
                .setOngoing(true)
                .build()

        service.startForeground(LOCATION_NOTIFICATION_ID, notification)
        mgr.cancel(LOCATION_NOTIFICATION_ID)
        mgr.notify(LOCATION_NOTIFICATION_ID, notification)
    }
}

// remove notification for location service
fun removeServiceNotification(service: Service) {
  val notificationManager = service.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
  notificationManager?.cancel(LOCATION_NOTIFICATION_ID)
}

companion object {
    val LOCATION_NOTIFICATION_ID = 1001
    val NOTIFICATION_CHANNEL_ID = "myAppName"
}