Get Apple watch heartRateVariabilitySDNN realtime?

问题

I am using below function to get heartRateVariabilitySDNN, but its get only once and not calculate realtime like hearbeat does?

func HRVstart() { guard let quantityType = HKObjectType.quantityType(forIdentifier: .heartRateVariabilitySDNN) else { return }

                self.healthStore.execute(self.HRVStreamingQuery())

                // Create query to receive continiuous heart rate samples.
                let datePredicate = HKQuery.predicateForSamples(withStart: Date(), end: nil, options: .strictStartDate)
                let devicePredicate = HKQuery.predicateForObjects(from: [HKDevice.local()])
                let queryPredicate = NSCompoundPredicate(andPredicateWithSubpredicates:[datePredicate, devicePredicate])
                let updateHandler: HKQueryUpdateHandler = { [weak self] query, samples, deletedObjects, queryAnchor, error in
                    if let quantitySamples = samples as? [HKQuantitySample] {
                        self?.HRVprocess(samples: quantitySamples)
                    }
                }
                let query = HKAnchoredObjectQuery(type: quantityType,
                                                  predicate: queryPredicate,
                                                  anchor: nil,
                                                  limit: HKObjectQueryNoLimit,
                                                  resultsHandler: updateHandler)
                query.updateHandler = updateHandler

                // Execute the heart rate query.
                healthStore.execute(query)

                // Remember all active Queries to stop them later.
                self.HRVactiveQueries.append(query)
            }

    private func HRVStreamingQuery() -> HKQuery {
            let predicate = HKQuery.predicateForSamples(withStart: NSDate() as Date, end: nil, options: .strictStartDate)

            let query = HKAnchoredObjectQuery(type: self.heartRateVaribalityType, predicate: nil, anchor: nil, limit: Int(HKObjectQueryNoLimit)) {
                (query, samples, deletedObjects, anchor, error) -> Void in
                self.HRVformatSamples(samples: samples)
            }

            query.updateHandler = { (query, samples, deletedObjects, anchor, error) -> Void in
                self.HRVformatSamples(samples: samples)
            }
            self.HRVactiveQueries.append(query)

            return query
        }
  private func HRVformatSamples(samples: [HKSample]?) {

        guard let samples = samples as? [HKQuantitySample] else { return }
        guard let quantity = samples.last?.quantity else { return }
        let beats = quantity.doubleValue(for: HKUnit.secondUnit(with: .milli))
        let timestamp = samples[0].endDate

        let newHeartRateVariablity = HeartRateVariablity(timestamp: timestamp, hrv: beats)

        delegate?.heartRateVariablity(didChangeTo: newHeartRateVariablity)


        print("HeartRateVariablity: \(beats)")
    }

来源：https://stackoverflow.com/questions/61081308/get-apple-watch-heartratevariabilitysdnn-realtime

标签

ios

swift

apple-watch

healthkit

watchos