从 HealthKit 查询更新 SwiftUI

Posted 2023-03-10

【中文标题】从 HealthKit 查询更新 SwiftUI

【英文标题】：Updating SwiftUI from HealthKit Query

【发布时间】：2021-05-09 13:22:12

【问题描述】：

我想在 SwiftUI 中通过 ContentView 输出变量“healthStore.valueTest”。

类 healthStore 的结构如下：

class HealthStore 
    
    var healthStore: HKHealthStore?
    var query: HKStatisticsQuery?
    var valueTest: HKQuantity?
    
    
    init() 
        if HKHealthStore.isHealthDataAvailable() 
            healthStore = HKHealthStore()
        
    
    
    func calculateBloodPressureSystolic() 
        
        guard let bloodPressureSystolic = HKObjectType.quantityType(forIdentifier: .bloodPressureSystolic) else 
            // This should never fail when using a defined constant.
            fatalError("*** Unable to get the bloodPressure count ***")
        

        
//        let startDate = Calendar.current.date(byAdding: .day, value: -7, to: Date())
//        let anchorDate = Date.mondayAt12AM()
//        let daily = DateComponents(day: 1)
//        let predicate = HKQuery.predicateForSamples(withStart: startDate, end: Date(), options: .strictStartDate)
        
        query = HKStatisticsQuery(quantityType: bloodPressureSystolic,
                                                quantitySamplePredicate: nil,
                                                options: .discreteAverage) 
                                                query, statistics, error in
            
                                                DispatchQueue.main.async
                                                    self.valueTest = statistics?.averageQuantity()
                                                

                                                    
        
        
        healthStore!.execute(query!)
        
    

ContentView 构建如下：

import SwiftUI
import HealthKit

struct ContentView: View 
    
    private var healthStore: HealthStore?
               
    init() 
        healthStore = HealthStore()
    
    
    
    var body: some View 
        Text("Hello, world!")
            .padding().onAppear()
                
        if let healthStore = healthStore 
            healthStore.requestAuthorization  success in
                if success 
                    healthStore.calculateBloodPressureSystolic()
                    print(healthStore.query)
                    print(healthStore.valueTest)
                    
                
            
        
    


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

变量 self.valueTest 的值在进程 DispatchQueue.main.async 中分配。尽管如此，当通过 ContentView 查询时，我只得到一个 nil。

【参考方案1】：

您可以设置您的HealthStore 类并将其用作环境对象。假设您的应用使用 SwiftUI 生命周期，您可以在应用的 @main 入口点将 HealthStore 注入到环境中。

import SwiftUI

@main
struct NameOfYourHeathApp: App 

    let healthStore = HealthStore()

    var body: some Scene 
        WindowGroup 
            ContentView()
                .environmentObject(healthStore)
        
    

将您的 HealthStore 类更改为此。 （我在下面的示例中删除了您注释掉的代码）

import HealthKit

class HealthStore: ObservableObject 

    var healthStore: HKHealthStore?
    var query: HKStatisticsQuery?
    var valueTest: HKQuantity?

    init() 
        if HKHealthStore.isHealthDataAvailable() 
            healthStore = HKHealthStore()
        
    

    // I moved the HealthStore conditional check out of your View logic 
    // and placed it here instead.
    func setUpHealthStore() 
        let typesToRead: Set = [
            HKQuantityType.quantityType(forIdentifier: .bloodPressureSystolic)!
        ]

        // I left the `toShare` as nil as I did not dig into adding bloodpressure reading to HealthKit.
        healthStore?.requestAuthorization(toShare: nil, read: typesToRead, completion:  success, error in
            if success 
                self.calculateBloodPressureSystolic()
            
        )

    

    func calculateBloodPressureSystolic() 
        guard let bloodPressureSystolic = HKObjectType.quantityType(forIdentifier: .bloodPressureSystolic) else 
            // This should never fail when using a defined constant.
            fatalError("*** Unable to get the bloodPressure count ***")
        
        query = HKStatisticsQuery(quantityType: bloodPressureSystolic,
                                  quantitySamplePredicate: nil,
                                  options: .discreteAverage) 
            query, statistics, error in

            DispatchQueue.main.async
                self.valueTest = statistics?.averageQuantity()
            
        

        healthStore!.execute(query!)
    

然后像这样在你的ContentView 中使用它。

import SwiftUI

struct ContentView: View 

    @EnvironmentObject var healthStore: HealthStore

    var body: some View 
        Text("Hello, world!")
            .onAppear 
                healthStore.setUpHealthStore()
            
    

我没有在 .plist 文件中设置适当的权限，但您还需要设置健康共享使用说明和健康更新使用说明。我假设您已经这样做了，但我只是想提一下。

【讨论】：

当我在控制台打印变量 healthStore.valueTest 时，我只得到一个 nil。