No haptic feedback

Question

My watchos app relies on haptic feedback working in the background. I have searched and searched over the internet on how to do this and have only learnt how to add things to my info.plist

I do not want to use notifications to alert my user as its to cumbersome in terms of UI because this would be done too often.

I read about workout sessions but can't get this to work.

How do I allow haptic feedback to work while the wrist is lowered? The simplest way will be enough and I am not the most advanced with swift so please try explain fully!

An example of my code is below. Please show me where to put it if I want background haptic feedback to work:

My timer:

 _ = Timer.scheduledTimer(timeInterval: 88, target: self, selector: "action", userInfo: nil, repeats: true)

My action:

 func action() {
    print("action")
    WKInterfaceDevice.current().play(.success)
     imageObject.setImageNamed("number2")     
}

This is what I'm doing with HKWorkout session but have absolute no idea whats going on.

  func workoutSession(_ workoutSession: HKWorkoutSession, didChangeTo toState: HKWorkoutSessionState, from fromState: HKWorkoutSessionState, date: Date) {
    switch toState {
    case .running:
        workoutDidStart(date)
    case .ended:
        workoutDidEnd(date)
    default:
        print("Unexpected state \(toState)")
    }
}

func workoutSession(_ workoutSession: HKWorkoutSession, didFailWithError error: Error) {
    // Do nothing for now
    print("Workout error")
}


func workoutDidStart(_ date : Date) {
    if let query = createHeartRateStreamingQuery(date) {
        self.currenQuery = query
        healthStore.execute(query)
    } else {
        label.setText("cannot start")
    }
}

func workoutDidEnd(_ date : Date) {
    healthStore.stop(self.currenQuery!)
    label.setText("---")
    session = nil
}

// MARK: - Actions
@IBAction func startBtnTapped() {
    if (self.workoutActive) {
        //finish the current workout
        self.workoutActive = false
        self.startStopButton.setTitle("Start")
        if let workout = self.session {
            healthStore.end(workout)
        }
    } else {
        //start a new workout
        self.workoutActive = true
        self.startStopButton.setTitle("Stop")
        _ = Timer.scheduledTimer(timeInterval: 5, target: self, selector: "firsts", userInfo: nil, repeats: false)


        startWorkout()
    }

}

func startWorkout() {

    // If we have already started the workout, then do nothing.
    if (session != nil) {
        return
    }

    // Configure the workout session.
    let workoutConfiguration = HKWorkoutConfiguration()
    workoutConfiguration.activityType = .crossTraining
    workoutConfiguration.locationType = .indoor

    do {
        session = try HKWorkoutSession(configuration: workoutConfiguration)
        session?.delegate = self
    } catch {
        fatalError("Unable to create the workout session!")
    }

    healthStore.start(self.session!)
}

func createHeartRateStreamingQuery(_ workoutStartDate: Date) -> HKQuery? {


    guard let quantityType = HKObjectType.quantityType(forIdentifier: HKQuantityTypeIdentifier.heartRate) else { return nil }
    let datePredicate = HKQuery.predicateForSamples(withStart: workoutStartDate, end: nil, options: .strictEndDate )
    //let devicePredicate = HKQuery.predicateForObjects(from: [HKDevice.local()])
    let predicate = NSCompoundPredicate(andPredicateWithSubpredicates:[datePredicate])


    let heartRateQuery = HKAnchoredObjectQuery(type: quantityType, predicate: predicate, anchor: nil, 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}

    DispatchQueue.main.async {
        guard let sample = heartRateSamples.first else{return}
        let value = sample.quantity.doubleValue(for: self.heartRateUnit)
        self.label.setText(String(UInt16(value)))

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

func updateDeviceName(_ deviceName: String) {
    deviceLabel.setText(deviceName)
}

func animateHeart() {
    self.animate(withDuration: 0.5) {
        self.heart.setWidth(60)
        self.heart.setHeight(90)
    }

    let when = DispatchTime.now() + Double(Int64(0.5 * double_t(NSEC_PER_SEC))) / Double(NSEC_PER_SEC)

    DispatchQueue.global(qos: .default).async {
        DispatchQueue.main.asyncAfter(deadline: when) {
            self.animate(withDuration: 0.5, animations: {
                self.heart.setWidth(50)
                self.heart.setHeight(80)
            })            }


    }
}

Look I don't even need heart rate data or anything at all but the taptic engine buzzing in the background.

Answer 1

As an addition to my previous answer I created a sample project that shows how to trigger vibrations while in the background:

For a full example on how to use HKWorkoutSession check out my sample project on GitHub. The sample app will trigger a vibration every five seconds even with the app running in the background. HKWorkoutSession and thus the sample only work when the app was signed with a provisioning profile containing the HealthKit entitlement. Be sure to change the Development Team to your own Team for all three available targets. Xcode will try to create the needed provisioning profiles. If there are any signing issues or you use a wildcard provisioning profile running in the background will not work.