CODEWITHSUNDEEP
watchos-2healthkit
Deep Arora
Deep Arora

Reputation: 2040

Why HKSample array always have 1 value for a HKAnchoredObjectQuery with no limits,no predicate, no anchor?

I am trying to understand how HKAnchoredObjectQuery works. Once the workout started and workout session state changes to running, I call the following function to execute the query and get the Heart Beat Value.

func createHeartRateStreamingQuery() {

   guard let quantityType = HKObjectType.quantityTypeForIdentifier(HKQuantityTypeIdentifierHeartRate) else { return nil }

    var heartRateQuery : HKAnchoredObjectQuery? = HKAnchoredObjectQuery(type: quantityType, predicate: nil, anchor: nil, limit: Int(HKObjectQueryNoLimit)) { (query, sampleObjects, deletedObjects, newAnchor, error) -> Void in

    }

    heartRateQuery!.updateHandler = {(query, samples, deleteObjects, newAnchor, error) -> Void in
        {
           //Samples only have 1 entry which is the most recent reading.
        }
    }

    self.healthStore.executeQuery(heartRateQuery!)

}

HeartRateQuery's update handler is called every 2 to 3 seconds and samples variable in the completion handler is having only 1 reading of the Heart Rate which is the most current reading. Shouldn't it have all the readings of Heart Rate since the workout started since I have not set any limits, predicate or anchor on the query?

Upvotes: 0

Views: 251

Answers (1)

Allan
Allan

Reputation: 7363

The behavior you are seeing is expected. The updateHandler is only called with samples that are new since the handler was last invoked. If you want to keep track of the samples recorded during the workout then you should add them to an array each time the handler is called.

Note that because you are not using a predicate, the initial results block will include all heart rate samples that are currently available in HealthKit, not just the samples recorded during the workout session. You should probably constrain the query with a date predicate to only get the samples you are interested in.

Upvotes: 1

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