使用HealthKit时SwiftUI图表数据重复重绘问题求助

问题描述 #

从HealthKit读取静息心率数据时，使用带更新处理器的长期查询在后台新增数据，但每次关闭再打开应用，图表会异常重绘，下方列表也产生重复数据。尝试用.onDisappear修饰符停止查询，但仅在强制重启应用后才生效。疑问：这是否是SwiftUI Chart的问题？

相关代码 #

ViewModel部分

//Properties within my view model for resting HR.
var restingHRquery: HKStatisticsCollectionQuery?
@Published var restingHR: [RestingHeartRate] = [RestingHeartRate]()


    func calculateRestingHRData() {
        
        let restingHRpredicate = HKQuery.predicateForSamples(withStart: oneWeekAgo, end: nil, options: .strictStartDate)
        
        
        restingHRquery =   HKStatisticsCollectionQuery(quantityType: restingHeartRateType,
                                                       quantitySamplePredicate: restingHRpredicate,
                                                       options: .discreteAverage,
                                                       anchorDate: anchorDate,
                                                       intervalComponents: daily)
        
        
        restingHRquery!.initialResultsHandler = {
            restingQuery, statisticsCollection, error in
            
            //Handle errors here
            if let error = error as? HKError {
                switch (error.code) {
                case .errorHealthDataUnavailable:
                    return
                case .errorNoData:
                    return
                default:
                    return
                }
            }
            
            guard let statisticsCollection = statisticsCollection else { return}
            
            //Calculating resting HR
            statisticsCollection.enumerateStatistics(from: self.startDate, to: self.date) { statistics, stop in
                if let restHRquantity = statistics.averageQuantity() {
                    let hrdate = statistics.startDate
                    
                    //HR Units
                    let hrUnit = HKUnit(from: "count/min")
                    let restHRvalue = restHRquantity.doubleValue(for: hrUnit)
                    let restHR = RestingHeartRate(restingValue: Int(restHRvalue), date: hrdate)
                    
                    DispatchQueue.main.async {
                        self.restingHR.append(restHR)
                    }
                }
            }
        }
        
        restingHRquery!.statisticsUpdateHandler = {
            restingQuery, statistics, statisticsCollection, error in
            
            //Handle errors here
            if let error = error as? HKError {
                switch (error.code) {
                case .errorHealthDataUnavailable:
                    return
                case .errorNoData:
                    return
                default:
                    return
                }
            }
            
            guard let statisticsCollection = statisticsCollection else { return}
            
            //Calculating resting HR
            statisticsCollection.enumerateStatistics(from: self.startDate, to: self.date) { statistics, stop in
                if let restHRquantity = statistics.averageQuantity() {
                    let hrdate = statistics.startDate
                    
                    //HR Units
                    let hrUnit = HKUnit(from: "count/min")
                    let restHRvalue = restHRquantity.doubleValue(for: hrUnit)
                    let restHR = RestingHeartRate(restingValue: Int(restHRvalue), date: hrdate)
                    
                    DispatchQueue.main.async {
                        self.restingHR.append(restHR)
                    }
                }
            }
        }
        
        
        guard let restingHRquery = self.restingHRquery else { return }
      
        self.healthStore?.execute(restingHRquery)
    }

View部分

struct OneWeekRestHRChartView: View {
    @EnvironmentObject var healthStoreVM: HealthStoreViewModel
    
    var body: some View {
        
        VStack(alignment: .leading, spacing: 10) {
      
            Text("Average: \(healthStoreVM.averageRestHR) bpm")
                .font(.headline)
            
            Chart {
                ForEach(healthStoreVM.restingHR.reversed(), id: \.date) {
                    restHrData in
                    
                    LineMark(x: .value("day", restHrData.date, unit: .day),
                             y: .value("RHR", restHrData.restingValue)
                    )
                    .interpolationMethod(.catmullRom)
                    .foregroundStyle(.red)
                    .symbol() {
                        Circle()
                            .fill(.red)
                            .frame(width: 15)
                    }
                }
            }
            .frame(height: 200)
            .chartYScale(domain: 30...80)
            .chartXAxis {
                AxisMarks(values: .stride(by: .day)) {
                    AxisGridLine()
                    AxisValueLabel(format: .dateTime.day().month(), centered: true)
                    
                }
            }
        }
        .padding(.horizontal)
        .navigationTitle("Resting Heart Rate")

        
        List{
            ForEach(healthStoreVM.restingHR.reversed(), id: \.date) {
                restHR in
                
                DataListView(imageText: "heart.fill",
                             imageColor: .red,
                             valueText: "\(restHR.restingValue) bpm",
                             date: restHR.date)
            }
        }
        .listStyle(.inset)
    }
}

异常截图 #

这不是SwiftUI Chart的问题，核心原因是数据处理逻辑和查询生命周期管理不当：

核心问题点 #

1. 数据重复添加：每次调用calculateRestingHRData时，没有先清空restingHR数组，旧数据保留的同时新数据又被追加；且statisticsUpdateHandler里重新枚举了全部统计数据，导致所有数据被重复添加一遍。
2. 查询未正确停止：.onDisappear未生效，大概率是因为没有正确调用healthStore.stop(_:)终止查询，且ViewModel作为EnvironmentObject可能未被销毁，查询持续运行并向数组中添加数据。

修复方案 #

1. 初始化查询前清空数据
   在calculateRestingHRData方法开头添加：

   DispatchQueue.main.async {
       self.restingHR.removeAll()
   }
   

   避免旧数据残留导致重复。

2. 优化更新处理器逻辑
   statisticsUpdateHandler中的statistics参数就是新增的单条统计数据，无需遍历整个collection，直接处理这条数据即可：

   restingHRquery!.statisticsUpdateHandler = {
       restingQuery, statistics, statisticsCollection, error in
       
       // 错误处理保留
       if let error = error as? HKError {
           switch error.code {
           case .errorHealthDataUnavailable, .errorNoData:
               return
           default:
               return
           }
       }
       
       // 仅处理新增的单条统计数据
       guard let statistics = statistics,
             let restHRquantity = statistics.averageQuantity() else { return }
       
       let hrdate = statistics.startDate
       let hrUnit = HKUnit(from: "count/min")
       let restHRvalue = restHRquantity.doubleValue(for: hrUnit)
       let restHR = RestingHeartRate(restingValue: Int(restHRvalue), date: hrdate)
       
       DispatchQueue.main.async {
           // 可选：先检查是否已存在该日期的数据，避免重复
           if !self.restingHR.contains(where: { $0.date == hrdate }) {
               self.restingHR.append(restHR)
           }
       }
   }
   

3. 正确实现查询停止逻辑
   在ViewModel中添加停止查询的方法：

   func stopRestingHRQuery() {
       if let query = restingHRquery {
           healthStore?.stop(query)
           restingHRquery = nil
       }
   }
   

   然后在View的.onDisappear中调用：

   struct OneWeekRestHRChartView: View {
       @EnvironmentObject var healthStoreVM: HealthStoreViewModel
       
       var body: some View {
           // ... 原有View代码 ...
       }
       .onDisappear {
           healthStoreVM.stopRestingHRQuery()
       }
   }
   

4. 确保数据唯一性
   给RestingHeartRate实现Identifiable协议，或者用日期作为唯一标识去重，避免同一日期的数据被多次添加。

内容的提问来源于stack exchange，提问作者Kevin