[HealthKit]ヘルスケアデータにアクセスし、水泳のワークアウト、水泳のストローク数を取得し、出力する

ViewController.swift

import UIKit
import HealthKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        guard HKHealthStore.isHealthDataAvailable() else {
            return
        }
        
        let healthStore = HKHealthStore()

        let readDataTypes: Set<HKObjectType> = [HKWorkoutType.workoutType(),
                                                HKObjectType.quantityType(forIdentifier: .swimmingStrokeCount)!]

        healthStore.requestAuthorization(
            toShare: nil,
            read: readDataTypes,
            completion: {(success, error) in
                if success {
                    let predicate = HKQuery.predicateForWorkouts(with: HKWorkoutActivityType.swimming)
                    let sortDescriptor = NSSortDescriptor(key: HKSampleSortIdentifierStartDate, ascending: false)
                    let sampleQuery = HKSampleQuery(
                        sampleType: HKObjectType.workoutType(),
                        predicate: predicate,
                        limit: HKObjectQueryNoLimit,
                        sortDescriptors: [sortDescriptor],
                        resultsHandler: {(_, results, error) in
                            if error == nil {
                                let workouts = results as! [HKWorkout]
                                if let workout = workouts.first {
                                    print(workout.workoutEvents)
                                    let type = HKObjectType.quantityType(forIdentifier: .swimmingStrokeCount)!
                                    guard let workoutEvents = workout.workoutEvents else {
                                        return
                                    }

                                    for (index, workoutEvent) in workoutEvents.enumerated()  {
                                        // workoutEventのtypeにはlap, segment, pauseなどがあります
                                        if workoutEvent.type == .lap {
                                            let predicate = HKQuery.predicateForSamples(withStart: workoutEvent.dateInterval.start, end: workoutEvent.dateInterval.end, options: .strictStartDate)
                                            let query = HKStatisticsQuery(quantityType: type,
                                                                          quantitySamplePredicate: predicate,
                                                                          options: [.cumulativeSum]) { (_, statistic, error) in
                                                                              guard let statistic = statistic, error == nil else {
                                                                                  return
                                                                              }
                                                                              let sum = statistic.sumQuantity()?.doubleValue(for: HKUnit.count()) ?? 0
                                                                              print("stroke:\(sum) index:\(index)")
                                            }

                                            healthStore.execute(query)
                                        }
                                    }
                                }
                            }
                    })

                    healthStore.execute(sampleQuery)
                }
        })
    }
}