HKHeartbeatSeriesSample.swift

import SwiftUI
import HealthKit

struct ContentView: View {
    @State var labelText = "Get Data"
    @State var flag = false

    let healthStore = HKHealthStore()
    let allTypes = Set([
        HKSeriesType.heartbeat(),
        HKObjectType.quantityType(forIdentifier: .heartRate)!,
        HKQuantityType.quantityType(forIdentifier: .heartRateVariabilitySDNN)!,
        ])

    var body: some View {
        VStack() {
            Text(labelText)
                .font(.largeTitle)
                .padding(.bottom)
            Button(action: {
                if(self.flag) {
                    self.labelText = "Get Data"
                    self.flag = false
                } else {
                    if HKHealthStore.isHealthDataAvailable() {
                        self.labelText = "Succeeded!"
                        self.healthStore.requestAuthorization(toShare: nil, read: self.allTypes) { (success, error) in
                            let sortDescriptor = NSSortDescriptor(key: HKSampleSortIdentifierStartDate, ascending: false)
                            let query = HKSampleQuery(sampleType: HKSeriesType.heartbeat(),
                                predicate: nil,
                                limit: HKObjectQueryNoLimit,
                                sortDescriptors: [sortDescriptor]) { (_, samples, _) in
                                if let sample = samples?.first as? HKHeartbeatSeriesSample {
                                    print("series start:\(sample.startDate)\tend:\(sample.endDate)")
                                    let seriesQuery = HKHeartbeatSeriesQuery(heartbeatSeries: sample) {
                                        query, timeSinceSeriesStart, precededByGap, done, error in
                                        let formatted = String(format: "%.2f", timeSinceSeriesStart)
                                        print("timeSinceSeriesStart:\(formatted)\tprecededByGap:\(precededByGap)\t done:\(done)")
                                    }
                                    self.healthStore.execute(seriesQuery)
                                }
                            }
                            self.healthStore.execute(query)
                        }
                    } else {
                        self.labelText = "Unavailabe"

                    }
                    self.flag = true
                }
            }) {
                Text("Button")
                    .font(.largeTitle)
                    .foregroundColor(Color.white)
            }
                .padding(.all)
                .background(Color.blue)
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}