如何从HealthKit获取每日平均步数

Question

Im trying to display the daily amount of steps the user takes. But is don't really know how to manage this.

I already got this code:

let endDate = NSDate()
let startDate = NSCalendar.currentCalendar().dateByAddingUnit(.CalendarUnitMonth, value: -1, toDate: endDate, options: nil)

let weightSampleType = HKSampleType.quantityTypeForIdentifier(HKQuantityTypeIdentifierStepCount)
let predicate = HKQuery.predicateForSamplesWithStartDate(startDate, endDate: endDate, options: .None)

let query = HKSampleQuery(sampleType: weightSampleType, predicate: predicate, limit: 0, sortDescriptors: nil, resultsHandler: {
        (query, results, error) in
        if results == nil {
            println("There was an error running the query: \(error)")
        }

        dispatch_async(dispatch_get_main_queue()) {
            var dailyAVG = Int()
            var steps = results as [HKQuantitySample]
            for var i = 0; i < results.count; i++
            {
                //results[i] add values to dailyAVG
            }
        }
    })

 self.healthKitStore.executeQuery(query)

The query gets all the data needed as far as i know. But i don't know how to get the values out of the HKQuantitySample. So I cant test if the correct values are in the HKQuantitySample Array.

Answer 1

In case anyone else is trying to solve this in a not-so-terrible way...

At this time, it doesn't look like using HKStatisticsQuery or HKStatisticsCollectionQuery is possible for getting average step count. You can only use HKStatisticsOptionDiscreteAverage on a discrete data type. If you look at the header for HKTypeIdentifiers , you will see that HKQuantityTypeIdentifierStepCount is a cumulative data type.

If you try and fetch the average step count, Xcode spits out: Statistics option HKStatisticsOptionDiscreteAverage is not compatible with cumulative data type HKQuantityTypeIdentifierStepCount

Best Solution

Get the total number of steps a user has taken. You can specify a time period between two dates. Divide the total number of steps by however many days are between your two dates.

Answer 2

You need to loop through steps not results and then use each HKQuantitySample result's quantity property to get the number of steps in that sample, ex:

var dailyAVG:Double = 0
for steps in results as [HKQuantitySample]
{
   // add values to dailyAVG
   dailyAVG += steps.quantity.doubleValueForUnit(HKUnit.countUnit())
}