Cannot get today's steps to display into label - ios

Question

I am trying to create a label which displays today's steps from HealthKit. I have got as far as allowing HealthKit to read/write data, but I'm stuck on actually obtaining the data.
Can anyone offer any advice? Here's my code, including the label I want to display the steps:
import Foundation
import UIKit
import HealthKit
class HealthKitPage : UIViewController
{
let healthStore: HKHealthStore = HKHealthStore()
override func viewDidLoad()
{
var shareTypes = Set<HKSampleType>()
shareTypes.insert(HKQuantityType.quantityType(forIdentifier: HKQuantityTypeIdentifier.stepCount)!)
var readTypes = Set<HKObjectType>()
readTypes.insert(HKQuantityType.quantityType(forIdentifier: HKQuantityTypeIdentifier.stepCount)!)
healthStore.requestAuthorization(toShare: shareTypes, read: readTypes) { (success, error) -> Void in
if success {
print("success")
} else {
print("failure")
}
if let error = error { print(error) }
}
}
#IBOutlet weak var StepCount: UILabel!
}

Answer 1

You can fetch today's steps using HKStatisticsQuery. You can now in your view controller use getTodaysSteps method and set your label's text property.
Swift 3.1:
let healthStore = HKHealthStore()
func getTodaysSteps(completion: #escaping (Double) -> Void) {
let stepsQuantityType = HKQuantityType.quantityType(forIdentifier: .stepCount)!
let now = Date()
let startOfDay = Calendar.current.startOfDay(for: now)
let predicate = HKQuery.predicateForSamples(withStart: startOfDay, end: now, options: .strictStartDate)
let query = HKStatisticsQuery(quantityType: stepsQuantityType, quantitySamplePredicate: predicate, options: .cumulativeSum) { (_, result, error) in
var resultCount = 0.0
guard let result = result else {
log.error("Failed to fetch steps = \(error?.localizedDescription ?? "N/A")")
completion(resultCount)
return
}
if let sum = result.sumQuantity() {
resultCount = sum.doubleValue(for: HKUnit.count())
}
DispatchQueue.main.async {
completion(resultCount)
}
}
healthStore.execute(query)
}
You can call this method like this:
override func viewDidLoad() {
super.viewDidLoad()
getTodaysStepCount { [weak self] steps in
self?.StepCount.text = "\(steps)"
}
}