watchOS 8 HealtKit后台传送在后台运行几个小时后停止工作

Question

我正在尝试为一个独立的watchOS 8应用程序实现HealthKit数据的后台交付。我一直在关注Gettings the most out of HealthKit WWDC talk，似乎已经添加了后台交付工作所需的所有内容，包括最近的iOS 15和watchOS 8 com.apple.developer.healthkit.background-delivery授权。但由于某些原因，后台交付在应用程序转到后台后大约3-5小时后停止工作。例如，我在晚上收到应用程序的更新，但一夜之间更新就停止了，只有当我早上再次打开应用程序时，我才会收到更新。请参阅下面的ExtensionDelegate代码

class ExtensionDelegate: NSObject, WKExtensionDelegate {
    private let healthStore = HKHealthStore()
    private var anchor: HKQueryAnchor?

    func applicationDidFinishLaunching() {
        print("application did finish launching")

        activateHeathKit()
    }

    func activateHeathKit() {
        let types = Set([HKObjectType.categoryType(forIdentifier: .lowHeartRateEvent)!])

        healthStore.requestAuthorization(toShare: nil, read: types) { [weak self] success, _ in
            guard let `self` = self else {
                return
            }

            guard let lowHeartRateType = HKObjectType.categoryType(forIdentifier: .lowHeartRateEvent) else {
                return
            }

            `self`.healthStore.enableBackgroundDelivery(for: lowHeartRateType, frequency: .immediate) { success, _ in
                print("enableBackgroundDelivery: \(success) for lowHeartRateEvent")
            }

            let query = HKObserverQuery(sampleType: stepsType, predicate: nil) { _, completionHandler, error in
                `self`.updateLowHeartRate {
                    completionHandler()
                }
            }
            `self`.healthStore.execute(query)
        }
    }

    func updateLowHeartRate(completionHandler: @escaping () -> Void) {
        guard let lowHeartRateType = HKObjectType.categoryType(forIdentifier: .lowHeartRateEvent) else {return}

        let anchoredQuery = HKAnchoredObjectQuery(type: lowHeartRateType, predicate: nil, anchor:
                                                    self.anchor, limit: Int(HKObjectQueryNoLimit)) { [unowned self] query, newSamples,
            _, newAnchor, error -> Void in

            for item in newSamples ?? [] {
                let date = item.startDate
                let hour = Calendar.current.component(.hour, from: date)
                let minute = Calendar.current.component(.minute, from: date)

                let message = "Low heart rate from \(hour):\(String(format: "%02d", minute))"
                print(message)
            }

            self.anchor = newAnchor

            completionHandler()
        }

        healthStore.execute(anchoredQuery)
    }    
}

Answer 1

我没有看到用于后台任务的handle(_:)方法的实现，但可能只是没有显示出来。链接到文档here。

为了以防万一，这里是我如何设置我的锻炼应用程序，以更新手表表面的复杂性。

func handle(_ backgroundTasks: Set<WKRefreshBackgroundTask>) {
    for task in backgroundTasks {
        if WKExtension.shared().applicationState == .background {
            if let watchComplication = task as? WKApplicationRefreshBackgroundTask {
                // do background work here
            }
        }
        task.setTaskCompletedWithSnapshot(false)
    }
    completePendingTasksIfNeeded()
}