如何实现安卓防杀后台位置服务：随位置变化自动重启

核心思路 #

要满足「应用被杀后仍能触发、位置变化超100米才工作、低功耗」的需求，不能单纯依赖前台服务，必须结合系统级调度组件+低功耗状态感知+按需位置更新的组合方案，推荐用 WorkManager + Activity Transition API + Fused Location Provider 的被动更新模式，这是目前安卓平台最可靠的后台任务调度方案。

步骤1：用Activity Transition API实现低功耗状态感知 #

Transition API由系统层面监听设备活动状态，无需应用持续运行，能在设备从静止转为移动时触发后续任务，完美适配「静止停、移动启」的低功耗需求。

代码实现 #

1. 注册状态监听的Worker

class TransitionDetectionWorker(context: Context, params: WorkerParameters) : Worker(context, params) {
    private val activityRecognitionClient = ActivityRecognition.getClient(context)

    override fun doWork(): Result {
        // 监听从静止进入步行/乘车状态的变化
        val transitions = listOf(
            ActivityTransition.Builder()
                .setActivityType(DetectedActivity.STILL)
                .setActivityTransition(ActivityTransition.ACTIVITY_TRANSITION_EXIT)
                .build(),
            ActivityTransition.Builder()
                .setActivityType(DetectedActivity.ON_FOOT)
                .setActivityTransition(ActivityTransition.ACTIVITY_TRANSITION_ENTER)
                .build(),
            ActivityTransition.Builder()
                .setActivityType(DetectedActivity.IN_VEHICLE)
                .setActivityTransition(ActivityTransition.ACTIVITY_TRANSITION_ENTER)
                .build()
        )

        val request = ActivityTransitionRequest(transitions)
        val pendingIntent = PendingIntent.getBroadcast(
            context,
            0,
            Intent(context, TransitionReceiver::class.java),
            PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
        )

        activityRecognitionClient.requestActivityTransitionUpdates(request, pendingIntent)
            .addOnFailureListener {
                // 处理注册失败逻辑，比如重试
            }
        return Result.success()
    }
}

2. 接收状态变化的Broadcast Receiver

class TransitionReceiver : BroadcastReceiver() {
    override fun onReceive(context: Context?, intent: Intent?) {
        if (ActivityTransitionResult.hasResult(intent)) {
            val result = ActivityTransitionResult.extractResult(intent)
            result?.transitionEvents?.forEach { event ->
                // 检测到设备开始移动，触发位置追踪任务
                if ((event.activityType == DetectedActivity.ON_FOOT || event.activityType == DetectedActivity.IN_VEHICLE) &&
                    event.transitionType == ActivityTransition.ACTIVITY_TRANSITION_ENTER
                ) {
                    val workRequest = OneTimeWorkRequestBuilder<LocationTrackingWorker>()
                        .build()
                    WorkManager.getInstance(context!!).enqueue(workRequest)
                }
            }
        }
    }
}

步骤2：用WorkManager实现可靠的位置追踪调度 #

WorkManager是系统级任务调度器，即使应用被杀，也能保证任务被系统唤醒执行，同时可以按需启停位置更新，控制功耗。

位置追踪Worker实现 #

class LocationTrackingWorker(context: Context, params: WorkerParameters) : CoroutineWorker(context, params) {
    private lateinit var fusedLocationClient: FusedLocationProviderClient
    private var lastLocation: Location? = null
    private val locationCallback = object : LocationCallback() {
        override fun onLocationResult(locationResult: LocationResult?) {
            locationResult ?: return
            val currentLocation = locationResult.lastLocation ?: return
            
            lastLocation?.let {
                // 计算位置变化是否超过100米
                if (it.distanceTo(currentLocation) > 100) {
                    // 这里处理位置更新逻辑，比如上传服务器
                    handleLocationUpdate(currentLocation)
                }
            } ?: run {
                // 首次获取位置，记录基准点
                lastLocation = currentLocation
            }

            // 检查设备是否回到静止状态，若静止则停止追踪
            checkIfStill()
        }
    }

    override suspend fun doWork(): Result {
        fusedLocationClient = LocationServices.getFusedLocationProviderClient(applicationContext)
        val locationRequest = LocationRequest.create().apply {
            priority = LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY // 低功耗模式，避免持续唤醒GPS
            interval = 60000 // 1分钟更新一次，可按需调整
            fastestInterval = 30000
        }

        return try {
            fusedLocationClient.requestLocationUpdates(locationRequest, locationCallback, Looper.getMainLooper())
            Result.success()
        } catch (e: Exception) {
            Result.retry()
        }
    }

    private suspend fun checkIfStill() {
        val client = ActivityRecognition.getClient(applicationContext)
        val pendingIntent = PendingIntent.getBroadcast(
            applicationContext,
            1,
            Intent(applicationContext, StillCheckReceiver::class.java),
            PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
        )
        // 请求单次活动状态检测
        client.requestActivityUpdates(5000, pendingIntent)
    }

    private fun handleLocationUpdate(location: Location) {
        // 自定义位置处理逻辑
    }
}

静止状态检测Receiver

class StillCheckReceiver : BroadcastReceiver() {
    override fun onReceive(context: Context?, intent: Intent?) {
        if (ActivityRecognitionResult.hasResult(intent)) {
            val result = ActivityRecognitionResult.extractResult(intent)
            val mostProbableActivity = result.mostProbableActivity
            // 检测到静止，停止位置更新
            if (mostProbableActivity.type == DetectedActivity.STILL && mostProbableActivity.confidence >= 70) {
                val fusedClient = LocationServices.getFusedLocationProviderClient(context!!)
                fusedClient.removeLocationUpdates(PendingIntent.getBroadcast(
                    context,
                    1,
                    Intent(context, StillCheckReceiver::class.java),
                    PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
                ))
            }
        }
    }
}

步骤3：基础配置与初始化 #

1. Manifest注册组件 #

<receiver
    android:name=".TransitionReceiver"
    android:exported="false" />
<receiver
    android:name=".StillCheckReceiver"
    android:exported="false" />

<service
    android:name=".LocationService"
    android:foregroundServiceType="location" />

2. 应用启动时初始化监听任务 #

在启动页或Application类的onCreate中添加：

// 注册周期性的状态监听任务，确保应用重启后能重新监听
val transitionWorkRequest = PeriodicWorkRequestBuilder<TransitionDetectionWorker>(1, TimeUnit.DAYS)
    .build()
WorkManager.getInstance(this).enqueueUniquePeriodicWork(
    "TransitionDetection",
    ExistingPeriodicWorkPolicy.REPLACE,
    transitionWorkRequest
)

关键注意事项 #

• 权限要求：必须动态申请 ACCESS_FINE_LOCATION、ACCESS_BACKGROUND_LOCATION（Android10+）、ACTIVITY_RECOGNITION 权限，否则所有监听都会失效。
• 功耗优化：始终使用PRIORITY_BALANCED_POWER_ACCURACY，避免高精准度模式；静止时立即停止位置更新，不要持续监听；尽量减少前台服务的使用，仅在部分严格限制后台的厂商ROM中作为补充（显示低优先级通知）。
• 厂商适配：国产ROM（小米、华为、OPPO等）存在后台杀进程限制，必须引导用户将应用加入「后台白名单」或「自启动列表」，否则即使按上述方案实现，也可能被系统强制终止。

内容的提问来源于stack exchange，提问作者Siddy Hacks