How to implement iOS 11's MKUserTrackingButton

Question

I'm trying to implement a MKUserTrackingButton (which is new in iOS 11 SDK). This "button" actually inherits from UIView so I just put a UIView instance on my Map and in the Identity Inspector, linked it to the MKUserTrackingButton class, added an outlet in my code and in viewDidLoad().

I initialize it the following way:

self.centerMapButton = MKUserTrackingButton.init(mapView: self.mapView)

However, nothing works, I just have a blank view on my Map.

PS: Here's the WWDC 2017 session about this new feature (at 1:25): https://developer.apple.com/videos/play/wwdc2017/237/

Here's the method I call in viewDidLoad() to implement the button:

func setupUserTrackingButtonAndScaleView() {
    mapView.showsUserLocation = true

    let button = MKUserTrackingButton(mapView: mapView)
    button.layer.backgroundColor = UIColor(white: 1, alpha: 0.8).cgColor
    button.layer.borderColor = UIColor.white.cgColor
    button.layer.borderWidth = 1
    button.layer.cornerRadius = 5
    button.translatesAutoresizingMaskIntoConstraints = false
    view.addSubview(button)

    let scale = MKScaleView(mapView: mapView)
    scale.legendAlignment = .trailing
    scale.translatesAutoresizingMaskIntoConstraints = false
    view.addSubview(scale)

    NSLayoutConstraint.activate([button.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -10),
                                 button.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -10),
                                 scale.trailingAnchor.constraint(equalTo: button.leadingAnchor, constant: -10),
                                 scale.centerYAnchor.constraint(equalTo: button.centerYAnchor)])
}

Note that I have a mapView instance in my ViewController, of course.

Answer 1

I just ran your code against my MapKit app and it worked fine. Make sure you are passing the proper mapView instance to the MKUserTrackingButton.