MKAnnontation pin 图像调整大小问题

Question

MKAnnotation 的自定义 pin 图像。当点击或缩放地图时，自定义别针会被拉伸，并且主页地图汽车别针标记的开口尺寸很大。这是我在 mapview 中得到的输出结果：

这是我目前尝试过的代码：

var pin = MKAnnotationView()
var userPinView: MKAnnotationView!

if annotation is MKUserLocation {

    pin = mapView.view(for: annotation) ?? MKAnnotationView(annotation: annotation, reuseIdentifier: nil)
    let pinImage = UIImage(named: "carIcon3")
    let size = CGSize(width: 38, height: 44)
    UIGraphicsBeginImageContext(size)
    pinImage!.draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
    let resizedImage = UIGraphicsGetImageFromCurrentImageContext()
    pin.image = resizedImag
    userPinView = pin
    userPinView.contentMode = .scaleAspectFill
    userPinView.clipsToBounds = true
    return pin
}

if !(annotation is MKPointAnnotation) {
    return nil
}

let annotationIdentifier = "AnnotationIdentifier"
var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: annotationIdentifier)

if annotationView == nil {
    annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: annotationIdentifier)
    //            annotationView!.canShowCallout = true
} else {
    annotationView!.annotation = annotation
}
return annotationView

如何得到这样的结果：

尝试使用用户当前位置标记。但它崩溃了

   func locationManager(_ manager: CLLocationManager, didUpdateHeading newHeading: CLHeading) {

        UIView.animate(withDuration: 0.005) {

        let angle = newHeading.trueHeading.toRadians() // convert from degrees to radians

        self.userPinView.transform = CGAffineTransform(rotationAngle: CGFloat(angle)) // rotate the picture
    }
}

这里是我为位置注释执行 didselect 和取消选择的代码。

     func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {

    if annotView == true {

        let heights = 70

        let widths = 50

        UIView.animate(withDuration: 0.5, delay: 0.0, options: .curveLinear, animations: {

            view.frame.size = CGSize(width: widths, height: heights)

        })
    }

}

func mapView(_ mapView: MKMapView, didDeselect view: MKAnnotationView) {

    let heights = 70

    let widths = 50

    UIView.animate(withDuration: 0.5, delay: 0.0, options: .curveLinear, animations: {

        view.frame.size = CGSize(width: view.frame.width - CGFloat(widths), height: view.frame.height - CGFloat(heights))

    })
}

Answer 1

虽然我无法重现该问题，但建议进行一些更改：

1. 分离视图配置逻辑，让MKAnnotationView子类化，像这样：

   class CarAnnotationView: MKAnnotationView {
       override var annotation: MKAnnotation? {
           didSet {
               let size = CGSize(width: 38, height: 44)
               UIGraphicsBeginImageContext(size)
               UIImage(named: "carIcon")?.draw(in: CGRect(origin: .zero, size: size))
               self.image = UIGraphicsGetImageFromCurrentImageContext()
               UIGraphicsEndImageContext()
           }
       }
   }
   

2. 在mapView(_:viewFor:) 内更改以利用可重用视图，如下所示：

   func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
       if annotation is MKUserLocation {
           userPinView = mapView.dequeueReusableAnnotationView(withIdentifier: "carId") as? CarAnnotationView
           if (userPinView == nil) {
               userPinView = CarAnnotationView(annotation: nil, reuseIdentifier: "carId")
           }
   
           userPinView.annotation = annotation
           userPinView.setNeedsLayout()
           // userPinView.centerOffset = CGPoint(x: 0, y: -view.bounds.midY)
   
           return userPinView
       }
   
       guard annotation is MKPointAnnotation else { return nil }
   
       let annotationIdentifier = "AnnotationIdentifier"
       ...
       return annotationView
   
   }
   

3. 删除不必要的变量

   var pin = MKAnnotationView()