使用 MapKit 将视图居中到用户位置的按钮

MapKit 中是否有一个专用按钮可以将相机置于用户位置的中心？或者我是否必须手动创建按钮和切换mapView.showsUserLocation = true?

这种方式运行良好（Swift），并且可以自定义按钮：

class YourViewController{
   ...
   @IBOutlet weak var mapView:MKMapView
   ...

   override func viewDidLoad() {
      super.viewDidLoad()
      ...
      addMapTrackingButton()
   }

   func addMapTrackingButton(){
      let image = UIImage(named: "trackme") as UIImage?
      let button   = UIButton(type: UIButtonType.System) as UIButton
      button.frame = CGRectMake(5, 5, 35, 35)
      button.setImage(image, forState: .Normal)
      button.backgroundColor = .clearColor()
      button.addTarget(self, action: #selector(YourViewController.centerMapOnUserButtonClicked), forControlEvents:.TouchUpInside)
      self.mapView.addSubview(button)
   }

   func centerMapOnUserButtonClicked() {
      self.mapView.setUserTrackingMode( MKUserTrackingMode.Follow, animated: true)
   }
   ...
}

Swift 4:

func addMapTrackingButton(){
    let image = UIImage(named: "trackme") as UIImage?
    let button   = UIButton(type: UIButtonType.custom) as UIButton
    button.frame = CGRect(origin: CGPoint(x:5, y: 25), size: CGSize(width: 35, height: 35))
    button.setImage(image, for: .normal)
    button.backgroundColor = .clear
    button.addTarget(self, action: #selector(ViewController.centerMapOnUserButtonClicked), for:.touchUpInside)
    mapView.addSubview(button)
}

@objc func centerMapOnUserButtonClicked() {
    mapView.setUserTrackingMode(MKUserTrackingMode.follow, animated: true)
}