上一篇我們介紹了如果創(chuàng)建Apple Watch項目，以及簡單的顯示UI、創(chuàng)建交互。這一篇我們將通過HealthKit實現(xiàn)在Apple Watch上實時顯示用戶的心率情況。

1、創(chuàng)建項目

同上一篇一樣，我們只創(chuàng)建適用于Watch的App項目，項目名稱為MyHeartRate

創(chuàng)建項目

2、創(chuàng)建工具類HeartRateManager

創(chuàng)建新的Swift文件，名稱為HeartRateManager，用于請求權限、獲取心率數(shù)據(jù)。完整代碼如下：

import UIKit
import HealthKit

class HeartRateManager: NSObject,ObservableObject,HKWorkoutSessionDelegate,HKLiveWorkoutBuilderDelegate {
    @Published var state:Bool = false
    @Published var heartRate: Double = 0
    private var session:HKWorkoutSession!
    private var builder: HKLiveWorkoutBuilder!
    private let healthStore = HKHealthStore()
    
    /// 公開方法：請求權限
    func getAuthorization() {
        let typesToShare: Set = [
            HKQuantityType.workoutType()
        ]
        
        // 心率
        let heartRate =  HKQuantityType.quantityType(forIdentifier: .heartRate)
        let typesToRead:Set = [heartRate!]
        
        // 請求所需權限
        healthStore.requestAuthorization(toShare: typesToShare, read: typesToRead) { (succ, error) in
            if !succ {
                fatalError("Error requesting authorization from health store: \(String(describing: error)))")
            }
        }
    }
    
    /// 公開方法：開始健身
    func startWorkout() {
        /// 健身類型
        let configuration = HKWorkoutConfiguration()
        configuration.activityType = .mindAndBody
        configuration.locationType = .indoor
        
        do {
            session = try HKWorkoutSession(healthStore: healthStore, configuration: configuration)
            builder = session.associatedWorkoutBuilder()
        } catch {
            fatalError("Unable to create the workout session!")
        }
        
        // 設置session and builder.
        session.delegate = self
        builder.delegate = self
        
        /// 設置 builder的數(shù)據(jù)源
        builder.dataSource = HKLiveWorkoutDataSource(healthStore: healthStore, workoutConfiguration: configuration)
        // 開始健身session和開始監(jiān)聽數(shù)據(jù)
        session.startActivity(with: Date())
        builder.beginCollection(withStart: Date()) { (succ, error) in
            if !succ {
                fatalError("Error beginning collection from builder: \(String(describing: error)))")
            }
        }
        DispatchQueue.main.async { [weak self] in
            self?.state = true
        }
    }
    
    // 公開方法：停止健身session
    func stopWorkout() {
        session.end()
        builder.endCollection(withEnd: Date()) { (success, error) in
            self.builder.finishWorkout { (workout, error) in
                DispatchQueue.main.async() {
                    self.session = nil
                    self.builder = nil
                }
            }
        }
        DispatchQueue.main.async { [weak self] in
            self?.state = false
        }
    }
    
    /// 數(shù)據(jù)更新回調
    func workoutBuilder(_ workoutBuilder: HKLiveWorkoutBuilder, didCollectDataOf collectedTypes: Set<HKSampleType>) {
        for type in collectedTypes {
            if let quantityType = type as? HKQuantityType {
                switch quantityType {
                case HKQuantityType.quantityType(forIdentifier: .heartRate):
                    let statistics = workoutBuilder.statistics(for: quantityType)
                    let heartRateUnit = HKUnit.count().unitDivided(by: HKUnit.minute())
                    let value = statistics!.mostRecentQuantity()?.doubleValue(for: heartRateUnit)
                    let stringValue = String(Int(Double(round(1 * value!) / 1)))
                    DispatchQueue.main.async {
                        self.heartRate = Double(round(1 * value!) / 1)
                    }
                default:
                    return
                }
            }
        }
    }
    
    func workoutBuilderDidCollectEvent(_ workoutBuilder: HKLiveWorkoutBuilder) {
        // Retreive the workout event.
        guard let workoutEventType = workoutBuilder.workoutEvents.last?.type else { return }
        print("[workoutBuilderDidCollectEvent] Workout Builder changed event: \(workoutEventType.rawValue)")
    }
    
    func workoutSession(_ workoutSession: HKWorkoutSession, didChangeTo toState: HKWorkoutSessionState, from fromState: HKWorkoutSessionState, date: Date) {
        print("[workoutSession] Changed State: \(toState.rawValue)")
    }
    
    func workoutSession(_ workoutSession: HKWorkoutSession, didFailWithError error: Error) {
        print("[workoutSession] Encountered an error: \(error)")
    }
    
}

定義getAuthorization、startWorkout和stopWorkout三個方法，供后面的UI調用。而最底部的4個方法分別是HKWorkoutSessionDelegate,HKLiveWorkoutBuilderDelegate協(xié)議要求實現(xiàn)的。

3、創(chuàng)建UI

回到ContentView，利用上一步的HeartRateManager提供的數(shù)據(jù)和方法更新頁面數(shù)據(jù)以及實現(xiàn)交互，完整代碼如下：

import SwiftUI

struct ContentView: View {
    @StateObject private var heartRateManager = HeartRateManager()
    
    var body: some View {
        if heartRateManager.state {
            VStack {
                Text("心率:\(Int(heartRateManager.heartRate))")
                    .font(.title2)
                Button(action: {
                    heartRateManager.stopWorkout()
                }) {
                    Text("結束")
                        .font(.headline)
                }
            }
        }else {
            VStack {
                Button(action: {
                    heartRateManager.startWorkout()
                }) {
                    Text("開始")
                        .font(.headline)
                }
            }.onAppear() {
                heartRateManager.getAuthorization()
            }
        }
    }
}

4、添加權限

在Targets-MyHeartRateWatch-Sigining&Capabilities中添加HealthKit：

Capability

在info.plist文件中，添加對應讀寫健康數(shù)據(jù)權限的描述：

權限

5、運行查看效果

運行后，點擊開始按鈕，即可實時查看心率：

效果

完整代碼下載

下一篇，將實現(xiàn)將心率數(shù)據(jù)實時傳輸給iOS APP