Display a user's approximate location

import Mapbox
 
class ViewController: UIViewController, MGLMapViewDelegate {
var mapView: MGLMapView?
var preciseButton: UIButton?
 
override func viewDidLoad() {
super.viewDidLoad()
 
let mapView = MGLMapView(frame: view.bounds)
mapView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
mapView.delegate = self
mapView.showsUserLocation = true
self.mapView = mapView
 
view.addSubview(mapView)
}
 
/**
In order to enable the alert that requests temporary precise location,
please add the following key to your info.plist
`NSLocationTemporaryUsageDescriptionDictionary`
 
You must then add
`MGLAccuracyAuthorizationDescription`
as a key in the Privacy - Location Temporary Usage Description Dictionary
*/
@available(iOS 14, *)
func mapView(_ mapView: MGLMapView, didChangeLocationManagerAuthorization manager: MGLLocationManager) {
guard let accuracySetting = manager.accuracyAuthorization?() else { return }
 
if accuracySetting == .reducedAccuracy {
addPreciseButton()
} else {
removePreciseButton()
}
}
 
@available(iOS 14, *)
func addPreciseButton() {
let preciseButton = UIButton(frame: CGRect.zero)
preciseButton.setTitle("Turn Precise On", for: .normal)
preciseButton.backgroundColor = .gray
 
preciseButton.addTarget(self, action: #selector(requestTemporaryAuth), for: .touchDown)
self.view.addSubview(preciseButton)
self.preciseButton = preciseButton
 
// constraints
preciseButton.translatesAutoresizingMaskIntoConstraints = false
preciseButton.widthAnchor.constraint(equalToConstant: 150.0).isActive = true
preciseButton.heightAnchor.constraint(equalToConstant: 40.0).isActive = true
preciseButton.topAnchor.constraint(equalTo: view.topAnchor, constant: 100.0).isActive = true
preciseButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
}
 
@available(iOS 14, *)
@objc private func requestTemporaryAuth() {
guard let mapView = self.mapView else { return }
 
let purposeKey = "MGLAccuracyAuthorizationDescription"
mapView.locationManager.requestTemporaryFullAccuracyAuthorization!(withPurposeKey: purposeKey)
}
 
private func removePreciseButton() {
guard let button = self.preciseButton else { return }
button.removeFromSuperview()
self.preciseButton = nil
}
}