Updating the label with current heart rate (swift and watch kit) - ios

Question

When you click on the button the current heart rate should be captured and the label should be updated. But, I do not understand why the label won't get updated with the heart rate value. I do not know what is wrong here.
I am still a very beginner in terms of swift and watch kit. I hope anyone can help me out.
Thank you very much.
Below you can see the code. I have also added the authorization part into the AppDelegate.swift file.
import WatchKit
import Foundation
import HealthKit
class InterfaceController: WKInterfaceController {
#IBOutlet weak var label: WKInterfaceLabel!
#IBOutlet weak var button: WKInterfaceButton!
var isRecording = false
//For workout session
let healthStore = HKHealthStore()
var session: HKWorkoutSession?
var currentQuery: HKQuery?
override func awake(withContext context: Any?) {
super.awake(withContext: context)
// Configure interface objects here.
}
override func willActivate() {
// This method is called when watch view controller is about to be visible to user
super.willActivate()
//Check HealthStore
guard HKHealthStore.isHealthDataAvailable() == true else {
print("Health Data Not Avaliable")
return
}
}
override func didDeactivate() {
// This method is called when watch view controller is no longer visible
super.didDeactivate()
}
#IBAction func btnPressed() {
if(!isRecording){
let stopTitle = NSMutableAttributedString(string: "Stop Recording")
stopTitle.setAttributes([NSAttributedString.Key.foregroundColor: UIColor.red], range: NSMakeRange(0, stopTitle.length))
button.setAttributedTitle(stopTitle)
isRecording = true
startWorkout() //Start workout session/healthkit streaming
}else{
let exitTitle = NSMutableAttributedString(string: "Start Recording")
exitTitle.setAttributes([NSAttributedString.Key.foregroundColor: UIColor.green], range: NSMakeRange(0, exitTitle.length))
button.setAttributedTitle(exitTitle)
isRecording = false
healthStore.end(session!)
label.setText("Heart Rate")
}
}
}
extension InterfaceController: HKWorkoutSessionDelegate{
func workoutSession(_ workoutSession: HKWorkoutSession, didChangeTo toState: HKWorkoutSessionState, from fromState: HKWorkoutSessionState, date: Date) {
switch toState {
case .running:
print(date)
if let query = heartRateQuery(date){
self.currentQuery = query
healthStore.execute(query)
}
//Execute Query
case .ended:
//Stop Query
healthStore.stop(self.currentQuery!)
session = nil
default:
print("Unexpected state: \(toState)")
}
}
func workoutSession(_ workoutSession: HKWorkoutSession, didFailWithError error: Error) {
//Do Nothing
}
func startWorkout(){
// If a workout has already been started, do nothing.
if (session != nil) {
return
}
// Configure the workout session.
let workoutConfiguration = HKWorkoutConfiguration()
workoutConfiguration.activityType = .running
workoutConfiguration.locationType = .outdoor
do {
session = try HKWorkoutSession(configuration: workoutConfiguration)
session?.delegate = self
} catch {
fatalError("Unable to create workout session")
}
healthStore.start(self.session!)
print("Start Workout Session")
}
func heartRateQuery(_ startDate: Date) -> HKQuery? {
let quantityType = HKObjectType.quantityType(forIdentifier: HKQuantityTypeIdentifier.heartRate)
let datePredicate = HKQuery.predicateForSamples(withStart: startDate, end: nil, options: .strictEndDate)
let predicate = NSCompoundPredicate(andPredicateWithSubpredicates:[datePredicate])
let heartRateQuery = HKAnchoredObjectQuery(type: quantityType!, predicate: predicate, anchor: nil, limit: Int(HKObjectQueryNoLimit)) { (query, sampleObjects, deletedObjects, newAnchor, error) -> Void in
//Do nothing
}
heartRateQuery.updateHandler = {(query, samples, deleteObjects, newAnchor, error) -> Void in
guard let samples = samples as? [HKQuantitySample] else {return}
DispatchQueue.main.async {
guard let sample = samples.first else { return }
let value = sample.quantity.doubleValue(for: HKUnit(from: "count/min"))
print("This line is executed!")
self.label.setText(String(UInt16(value))) //Update label
}
}
return heartRateQuery
}
}
import UIKit
import HealthKit
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
return true
}
func applicationWillResignActive(_ application: UIApplication) {
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
}
func applicationDidEnterBackground(_ application: UIApplication) {
// Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
// If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}
func applicationWillEnterForeground(_ application: UIApplication) {
// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
}
func applicationDidBecomeActive(_ application: UIApplication) {
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}
func applicationWillTerminate(_ application: UIApplication) {
// Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}
let healthStore = HKHealthStore()
func applicationShouldRequestHealthAuthorization(_ application: UIApplication) {
healthStore.handleAuthorizationForExtension{
(success,error) in
}
}
}