使用 SwiftUI 和 Combine 根据授权状态有条件地显示视图？

Question

我正在构建一个 UI，我想在视图中根据 HealthKit 是否已获得授权来显示“启用”按钮或绿色复选标记。我还希望视图是反应式的，以便一旦您授权 HealthKit，视图就会从按钮动态更改为复选标记，但我无法弄清楚如何正确地进行这两种方式的通信以及属性要使用的包装器：

struct SetUpWatchView: View {

    let healthKitAuthManager = HealthKitAuthManager()
@ViewBuilder
    var body: some View {
            VStack(alignment: .leading) {
                HStack {
                     Image(systemName: "heart.circle.fill")
                     .foregroundColor(.red)
                      .font(.system(size: 56.0, weight: .bold))
                      .frame(width: 65, height: 65)
                    VStack(alignment: .leading) {
                        Text("Health Integration")
                            .fontWeight(.bold)
                        Text("Enable in Order to Track your Speed, Distance, and Heart Rate.")
                    }
                    Spacer()
                    if healthKitAuthManager.healthKitIsAuthorized {
                        Image(systemName: "checkmark.circle.fill")
                            .foregroundColor(.green)
                            .font(.system(size: 30.0, weight: .bold))
                             .padding(.horizontal)
                    } else {
                        Button(action: {
                            healthKitAuthManager.authorizeHealthKit()
                        }) {
                            Text("ENABLE")
                                .fontWeight(.bold)
                                .foregroundColor(Color.black)
                        }
                        .padding(.horizontal)
                    }
                }
                .padding([.leading, .bottom])
            }.onAppear {
                healthKitAuthManager.checkWhetherHealthKitDatAvailableAndIfAuthorized()
            }
        }
    }
}



class HealthKitAuthManager: ObservableObject {
    
    let healthStore = HKHealthStore()
    
    @Published var healthKitIsAuthorized = false
    
     public func checkWhetherHealthKitDatAvailableAndIfAuthorized()  {
        
        if HKHealthStore.isHealthDataAvailable() {
            
            let authorizationStatus = healthStore.authorizationStatus(for: HKSampleType.workoutType())
            switch authorizationStatus {
            case .sharingAuthorized:
                
                healthKitIsAuthorized = true
                
            case .sharingDenied: ()
             healthKitIsAuthorized = false
            default:()
              healthKitIsAuthorized = false
            }
            
        }
        else {
            healthKitIsAuthorized = false 
        }
    }

    public func authorizeHealthKit() {

        let healthKitTypesToWrite: Set<HKSampleType> = [
            HKObjectType.workoutType(),
            HKSeriesType.workoutRoute(),
            HKObjectType.quantityType(forIdentifier: .activeEnergyBurned)!,
            HKObjectType.quantityType(forIdentifier: .heartRate)!,
            HKObjectType.quantityType(forIdentifier: .restingHeartRate)!,
            HKObjectType.quantityType(forIdentifier: .bodyMass)!,
            HKObjectType.quantityType(forIdentifier: .vo2Max)!,
            HKObjectType.quantityType(forIdentifier: .stepCount)!,
            HKObjectType.quantityType(forIdentifier: .distanceWalkingRunning)!]

        let healthKitTypesToRead: Set<HKObjectType> = [
            HKObjectType.workoutType(),
            HKSeriesType.workoutRoute(),
            HKObjectType.quantityType(forIdentifier: .activeEnergyBurned)!,
            HKObjectType.quantityType(forIdentifier: .heartRate)!,
            HKObjectType.quantityType(forIdentifier: .restingHeartRate)!,
            HKObjectType.characteristicType(forIdentifier: .dateOfBirth)!,
            HKObjectType.quantityType(forIdentifier: .bodyMass)!,
            HKObjectType.quantityType(forIdentifier: .vo2Max)!,
            HKObjectType.quantityType(forIdentifier: .stepCount)!,
            HKObjectType.quantityType(forIdentifier: .distanceWalkingRunning)!]

        let authorizationStatus = HKHealthStore().authorizationStatus(for: HKSampleType.workoutType())

        switch authorizationStatus {

        case .sharingAuthorized:

            print("Sharing Authorized")
            healthKitIsAuthorized = true

        case .sharingDenied: print("sharing denied")

        //Success does NOT necessarily mean we are authorized, only that the request was successfully delivered.  Also if a user chooses not to authorize, if you call .requestAuthorization again you won't get the action sheet
        HKHealthStore().requestAuthorization(toShare: healthKitTypesToWrite, read: healthKitTypesToRead) { (success, error) in
            if !success {
                print("failed HealthKit Authorization from iPhone SetUpWatchVC \(String(describing: error?.localizedDescription))")
            }

            print("Successful HealthKit Authorization from iPhone")
            }

        default: print("not determined")

        HKHealthStore().requestAuthorization(toShare: healthKitTypesToWrite, read: healthKitTypesToRead) { (success, error) in
            if !success {
                print("failed HealthKit Authorization from iPhone SetUpWatchVC \(String(describing: error?.localizedDescription))")
            }

            print("Successful HealthKit Authorization from iPhone SetUpWatchVC")

            }

        }



    }

}

Answer 1

尝试添加 @ObservedObject var healthKitAuthManager = HealthKitAuthManager() 而不是 let healthKitAuthManager = HealthKitAuthManager()。这样 @Published 变量将触发新的视图渲染。

使用 SwiftUI 和 Combine 根据授权状态有条件地显示视图？

Using SwiftUI and Combine to conditionally display a view based on authorization status?

ios

swift

healthkit

swiftui

combine