How to query Healthkit for average heart rate with Swift

Question

I need to query HKStatistics for average heart rate, with Swift 2.2. I've learned from research the parameter I need is HKStatisticsOptionDiscreteAverage

I have code for the workout session. How can I add the function to this code below measuring heart-rate to return the heart rate average of the workout session with HKStatisticsOptionDiscreteAverage?

func createHeartRateStreamingQuery(workoutStartDate: NSDate) -> HKQuery? {
    // adding predicate will not work
    // let predicate = HKQuery.predicateForSamplesWithStartDate(workoutStartDate, endDate: nil, options: HKQueryOptions.None)

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

    let heartRateQuery = HKAnchoredObjectQuery(type: quantityType, predicate: nil, anchor: anchor, limit: Int(HKObjectQueryNoLimit)) { (query, sampleObjects, deletedObjects, newAnchor, error) -> Void in
        guard let newAnchor = newAnchor else {return} 
        self.anchor = newAnchor
        self.updateHeartRate(sampleObjects)
    }

    heartRateQuery.updateHandler = {(query, samples, deleteObjects, newAnchor, error) -> Void in
        self.anchor = newAnchor!
        self.updateHeartRate(samples)
    }
    return heartRateQuery
}

func updateHeartRate(samples: [HKSample]?) {
    guard let heartRateSamples = samples as? [HKQuantitySample] else {return}

    dispatch_async(dispatch_get_main_queue()) {
        guard let sample = heartRateSamples.first else{return}
        let value = sample.quantity.doubleValueForUnit(self.heartRateUnit)
        self.label.setText(String(UInt16(value)))

        // retrieve source from sample
        let name = sample.sourceRevision.source.name
        self.updateDeviceName(name)
        self.animateHeart()
    }
}

Answer 1

    func getAVGHeartRate() {

    var typeHeart = HKQuantityType.quantityType(forIdentifier: .heartRate)
    var startDate = Date() - 7 * 24 * 60 * 60 // start date is a week
    var predicate: NSPredicate? = HKQuery.predicateForSamples(withStart: startDate, end: Date(), options: HKQueryOptions.strictEndDate)

    var squery = HKStatisticsQuery(quantityType: typeHeart!, quantitySamplePredicate: predicate, options: .discreteAverage, completionHandler: {(query: HKStatisticsQuery,result: HKStatistics?, error: Error?) -> Void in
        DispatchQueue.main.async(execute: {() -> Void in
            var quantity: HKQuantity? = result?.averageQuantity()
            var beats: Double? = quantity?.doubleValue(for: HKUnit.count().unitDivided(by: HKUnit.minute()))
            print("got: \(String(format: "%.f", beats!))")
        })
        })
    healthStore.execute(squery)
}

This is the Swift 3 version :)

Answer 2

this is objective-c example of getting the average heart BPM:

HKQuantityType *typeHeart =[HKQuantityType quantityTypeForIdentifier:HKQuantityTypeIdentifierHeartRate];
NSPredicate *predicate = [HKQuery predicateForSamplesWithStartDate:startDate endDate:endDate options:HKQueryOptionStrictStartDate];

HKStatisticsQuery *squery = [[HKStatisticsQuery alloc] initWithQuantityType:typeHeart quantitySamplePredicate:predicate options:HKStatisticsOptionDiscreteAverage completionHandler:^(HKStatisticsQuery *query, HKStatistics *result, NSError *error) {
    dispatch_async(dispatch_get_main_queue(), ^{
        HKQuantity *quantity = result.averageQuantity;
        double beats = [quantity doubleValueForUnit:[[HKUnit countUnit] unitDividedByUnit:[HKUnit minuteUnit]]];
        NSLog(@"got: %@", [NSString stringWithFormat:@"%.f",beats]) ;

        }
    );

}];
[self.healthStore executeQuery:squery];