I'm building an app which generates sounds and needs to monitor their volume. I'm trying to use HealthKit for it and this is what I have done so far:

private let healthStore = HKHealthStore()

func observeHeadphoneAudio() {
    guard let type = HKObjectType.categoryType(forIdentifier: .headphoneAudioExposureEvent) else {
        return
    }
    healthStore.requestAuthorization(toShare: nil, read: [type]) { [weak self] success, error in
        if let error = error {
            log.warning(error.localizedDescription)
        } else if success {
            self?.fetch(type: type)
        }
    }
}

func fetch(type: HKCategoryType) {
    let descriptor = HKQueryDescriptor(sampleType: type, predicate: nil)
    let query = HKObserverQuery(queryDescriptors: [descriptor]) { query, samples, completion, error in
        if let error = error {
            log.warning(error.localizedDescription)
        }
        if let samples = samples {
            log.info(samples)
        }
    }
    healthStore.execute(query)
}

I'm starting it while generating a sound, query completion is executed once with empty samples set, and that's it.

What is the proper way to monitor headphone audio exposure?

CodePudding user response：

Are you looking for headphone audio exposure or headphone audio exposure event? The latter is generated when you exceed headphone audio exposure limits. See

https://developer.apple.com/documentation/healthkit/hkquantitytypeidentifier/3081272-headphoneaudioexposure/ https://developer.apple.com/documentation/healthkit/hkcategorytypeidentifier/3552059-headphoneaudioexposureevent

CodePudding user response：

I changed type of event to headphoneAudioExposure and created something like this:

private let healthStore = HKHealthStore()

func start() {
    authorize { [weak self] type in
        self?.runQuery(for: type)
    }
}

func authorize(successHandler: @escaping (HKQuantityType) -> Void ) {
    guard let type = HKObjectType.quantityType(forIdentifier: .headphoneAudioExposure) else {
        return
    }
    healthStore.requestAuthorization(toShare: nil, read: [type]) { success, error in
        if let error = error {
            log.warning(error.localizedDescription)
        } else if success {
            successHandler(type)
        } else {
            log.warning("Unknown error")
        }
    }
}

func runQuery(for type: HKQuantityType) {
    let startDate = Date()
    let predicate = HKQuery.predicateForSamples(withStart: startDate,
                                                end: .distantFuture,
                                                options: .strictStartDate)
    let interval = DateComponents(nanosecond: 500_000_000)

    let query = HKStatisticsCollectionQuery(quantityType: type,
                                            quantitySamplePredicate: predicate,
                                            options: .mostRecent,
                                            anchorDate: startDate,
                                            intervalComponents: interval)

    query.initialResultsHandler = { _, statisticsCollection, error in
        log.info("----------INITIAL-----------")
        if let error = error {
            log.warning(error.localizedDescription)
        } else if let lastStatistics = statisticsCollection?.statistics().last {
            log.info(lastStatistics.startDate)
            log.info(lastStatistics.endDate)
            log.info(lastStatistics.mostRecentQuantity())
        } else {
            log.warning("No statistics yet")
        }
        log.info("----------INITIAL-----------")
    }

    query.statisticsUpdateHandler = { _, statistics, _, error in
        if let error = error {
            log.warning(error.localizedDescription)
        } else if let statistics = statistics {
            log.info("---------UPDATE------------")
            log.info(statistics.startDate)
            log.info(statistics.endDate)
            log.info(statistics.mostRecentQuantity())
            log.info(statistics.quantityType)
        }
    }
    healthStore.execute(query)
}

Problem with this code is that sometime it's working sometime is not, and I have no idea why. Also, when I'm able to get some data in statisticsUpdateHandler they are coming in packets once per 60-70 seconds. Any suggestions, what am I doing wrong?