CODEWITHSUNDEEP
iosswifthealthkit
mike.b93
mike.b93

Reputation: 1999

Get bodyMass data from last 30 days from HealthKit with Swift

I'm learning Swift and HealthKit right now and am a bit stuck at retreiving data. I've already successfully queried my dietaryCaloriesConsumed for the last 30 days which is being printed to the console.

When I try to do the same with weight data I get no output. Although I'm able to get weight data from a specific date by counting the date backwards and using only the first sample.

My code right now:

    func getWeightData2(forDay days: Int, completion: @escaping ((_ weight: Double?, _ date: Date?) -> Void)) {
    // Getting quantityType as stepCount
    guard let weight = HKObjectType.quantityType(forIdentifier: .bodyMass) else {
        print("*** Unable to create a step count type ***")
        return
    }

    let now = Date()
    let startDate = Calendar.current.date(byAdding: DateComponents(day: -days), to: now)!

    var interval = DateComponents()
    interval.day = 1

    var anchorComponents = Calendar.current.dateComponents([.day, .month, .year], from: now)
    anchorComponents.hour = 0
    let anchorDate = Calendar.current.date(from: anchorComponents)!

    let query = HKStatisticsCollectionQuery(quantityType: weight,
                                            quantitySamplePredicate: nil,
                                            options: [.mostRecent],
                                            anchorDate: anchorDate,
                                            intervalComponents: interval)
    query.initialResultsHandler = { _, results, error in
        guard let results = results else {
            print("ERROR")
            return
        }

        results.enumerateStatistics(from: startDate, to: now) { statistics, _ in
            if let sum = statistics.sumQuantity() {
                let weight = Int(sum.doubleValue(for: HKUnit.gramUnit(with: .kilo)).roundToDecimal(2))
                                  print("Weight Tracked: \(weight), on date: \(statistics.endDate)")
                //                    completion(calories, statistics.endDate)
                return
            }
        }
        completion(nil, nil)
    }
    healthStore.execute(query)
}

With this I don't get any output. With slight changes for dietaryCaloriesConsumed I get 30 days worth of calories, summed up for each day (with option cumulativeSum)

What acutally does work is retreiving data for a specific day like this:

    func getWeightData(forDay days: Int) {
    let quantityType: HKQuantityType = HKQuantityType.quantityType(forIdentifier: .bodyMass)!

    // fetch last 30 days
    let startDate = Date.init(timeIntervalSinceNow: TimeInterval(-days*24*60*60))
    let endDate = Date()
    let predicate = HKQuery.predicateForSamples(withStart: startDate, end: endDate)

    let sampleQuery = HKSampleQuery.init(sampleType: quantityType, predicate: predicate, limit: HKObjectQueryNoLimit, sortDescriptors: nil) { (query, samples, error) in
        DispatchQueue.main.async {
            guard let samples = samples else { return }
            let mostRecentSample = samples.first as? HKQuantitySample
            let bodyMass = mostRecentSample?.quantity.doubleValue(for: HKUnit.gramUnit(with: .kilo)).roundToDecimal(2)
            print("Weight tracked: \(bodyMass) on date: \(endDate)")
    }
    }
    healthStore.execute(sampleQuery)
}

From my ViewController I call those functions like this:

profileStore.getTotalCalories(forDay: 30) {_,_   in
    }

and

profileStore.getWeightData(forDay: 30)

This works, but I'm sure there is much room for approval.

Any ideas what I'm doing wrong with my first code? What is the best way to get n days worth of dietaryCaloriesConsumed or bodyMass for further processing?

Thanks a lot :)

Upvotes: 1

Views: 1716

Answers (1)

mike.b93
mike.b93

Reputation: 1999

I just solved my own issue:

    func getWeightData(forDay days: Int, completion: @escaping ((_ weight: Double?, _ date: Date?) -> Void)) {
    // Getting quantityType as stepCount
    guard let bodyMassType = HKObjectType.quantityType(forIdentifier: .bodyMass) else {
        print("*** Unable to create a bodyMass type ***")
        return
    }

    let now = Date()
    let startDate = Calendar.current.date(byAdding: DateComponents(day: -days), to: now)!

    var interval = DateComponents()
    interval.day = 1

    var anchorComponents = Calendar.current.dateComponents([.day, .month, .year], from: now)
    anchorComponents.hour = 0
    let anchorDate = Calendar.current.date(from: anchorComponents)!

    // Note to myself:: StatisticsQuery!! Nicht Collection! Option .mostRecent. Achtung, unten auch setzen!!
    let query = HKStatisticsCollectionQuery(quantityType: bodyMassType,
                                            quantitySamplePredicate: nil,
                                            options: [.mostRecent],
                                            anchorDate: anchorDate,
                                            intervalComponents: interval)
    query.initialResultsHandler = { _, results, error in
        guard let results = results else {
            print("ERROR")
            return
        }

        results.enumerateStatistics(from: startDate, to: now) { statistics, _ in
            // hier wieder .mostRecent!
            if let sum = statistics.mostRecentQuantity() {
                let bodyMassValue = sum.doubleValue(for: HKUnit.gramUnit(with: .kilo)).roundToDecimal(2)
                completion(bodyMassValue, statistics.startDate)
                return
            } 
        }
    }
    healthStore.execute(query)
}

This loads data from the last n days and returns bodyMass as well as the date

Upvotes: 2

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