运行中前台服务因权限撤销触发SecurityException问题处理

崩溃的核心原因是API 34+ 对前台服务（FGS）的权限校验逻辑：当用户撤销位置权限后，WorkManager 会根据自身的任务恢复机制重启之前的位置 Worker，但此时调用setForeground()时，系统会校验FOREGROUND_SERVICE_LOCATION和位置访问权限，权限缺失直接抛出SecurityException导致崩溃。这种恢复是系统级的，仅在APP启动时取消任务可能赶不上Worker的恢复执行时机。

1. 在Worker内部前置权限检查（最关键） #

在调用setForeground()之前必须重新检查权限，一旦发现权限缺失，立即取消自身任务并返回失败，从根源避免崩溃：

override suspend fun doWork(): Result {
    return try {
        // 前置权限检查：同时校验前台服务权限和位置权限
        val hasFgsPermission = ContextCompat.checkSelfPermission(applicationContext, 
            Manifest.permission.FOREGROUND_SERVICE_LOCATION) == PackageManager.PERMISSION_GRANTED
        val hasLocationPermission = ContextCompat.checkSelfPermission(applicationContext,
            Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED ||
            ContextCompat.checkSelfPermission(applicationContext,
                Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED

        if (!hasFgsPermission || !hasLocationPermission) {
            // 权限缺失，取消当前Worker任务
            WorkManager.getInstance(applicationContext).cancelWorkById(id)
            notificationHelper.hideNotification(notificationId)
            return Result.failure()
        }

        // 权限正常，继续执行逻辑
        notificationHelper.showNotification(createNotification(), notificationId)
        setForeground(createForegroundInfo())
            
        withContext(dispatcher) {
            while (kotlin.coroutines.coroutineContext.isActive) {
                // 每次循环重新检查权限，防止中途被撤销
                val currentLocationPermission = ContextCompat.checkSelfPermission(applicationContext,
                    Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED ||
                    ContextCompat.checkSelfPermission(applicationContext,
                        Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED
                if (!currentLocationPermission) {
                    break
                }
                val location = getLocation()
                notificationHelper.showNotification(createNotification(), notificationId)
                delay(MINUTES_30)
            }
        }
        
        Result.success()
    } catch (e: Exception) {
        if (e is CancellationException) {
            Result.failure()
        } else {
            // 捕获SecurityException兜底处理
            if (e is SecurityException) {
                WorkManager.getInstance(applicationContext).cancelWorkById(id)
                notificationHelper.hideNotification(notificationId)
            }
            Timber.e(e)
            Result.failure()
        }
    }
}

2. 监听权限变更广播，主动取消Worker #

注册权限变更的广播接收器，当位置权限被撤销时，立即取消对应的WorkManager任务：

// 在Application或主Activity中动态注册广播
val permissionReceiver = object : BroadcastReceiver() {
    override fun onReceive(context: Context?, intent: Intent?) {
        if (intent?.action == Intent.ACTION_PERMISSION_CHANGED) {
            val hasLocationPermission = ContextCompat.checkSelfPermission(context!!,
                Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED ||
                ContextCompat.checkSelfPermission(context,
                    Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED
            
            if (!hasLocationPermission) {
                WorkManager.getInstance(context).cancelAllWorkByTag(WORK_NAME)
                notificationHelper.hideNotification(notificationId)
            }
        }
    }
}

// 注册广播（注意在合适时机注销，避免内存泄漏）
val filter = IntentFilter(Intent.ACTION_PERMISSION_CHANGED)
registerReceiver(permissionReceiver, filter)

3. 优化APP启动时的取消逻辑 #

在Application的onCreate()中尽早执行取消任务，配合Worker内部的检查覆盖系统恢复场景：

class MyApp : Application() {
    override fun onCreate() {
        super.onCreate()
        // 尽早取消位置Worker
        WorkManager.getInstance(this).cancelAllWorkByTag(WORK_NAME)
        notificationHelper.hideNotification(notificationId)
        
        // 可选：清理已完成的旧任务，减少冗余
        WorkManager.getInstance(this).pruneWork()
    }
}

• 不要依赖启动前的权限检查：Worker可能被系统自动恢复（比如APP进程被杀死后重启），此时之前的权限状态已失效，必须在Worker每次执行时重新检查。
• 捕获SecurityException兜底：即使做了前置检查，也可能存在竞态条件（比如检查后权限被立即撤销），所以必须在setForeground()的调用路径中捕获异常。
• 使用动态广播：Android 8.0+对静态广播限制严格，动态注册权限变更广播更可靠。

内容的提问来源于stack exchange，提问作者Dannie