MKMapView在加载注解时遇到问题

Question

我在加载MapView时无法放大注解/引脚。

加载MapView时，我希望它开始缩小，然后放大注释/引脚。 “动画”设置为“true”。我不确定这里有什么问题。

当地图加载完成后，它会短暂地显示一个灰色的屏幕，然后围绕它加载卫星地图。

谢谢！

使用斯威夫特3

地图代码：

@IBOutlet weak var mapView: MKMapView! 

    } 



    override func viewDidLoad() { 
     super.viewDidLoad() 


     let distanceSpan:CLLocationDegrees = 300 
     let redRocks:CLLocationCoordinate2D = CLLocationCoordinate2DMake(39.665496, -105.205438) 
     let redRocksPin = RedRocksPin(title: "Jerry Garcia 1/2/72", subtitle: "Red Rocks Amphitheatre", coordinate: redRocks) 
     mapView.addAnnotation(redRocksPin) 

     mapView.setRegion(MKCoordinateRegionMakeWithDistance(redRocks, distanceSpan, distanceSpan), animated: true) 

针类：

import MapKit 

class RedRocksPin: NSObject, MKAnnotation { 
var title: String? 
var subtitle: String? 
var coordinate: CLLocationCoordinate2D 

init(title:String, subtitle:String, coordinate: CLLocationCoordinate2D) { 
    self.title = title 
    self.subtitle = subtitle 
    self.coordinate = coordinate 
} 

Answer 1

在类声明使这些类变量：

let distanceSpan:CLLocationDegrees = 300 
    let redRocks:CLLocationCoordinate2D = CLLocationCoordinate2DMake(39.665496, -105.205438) 

在viewWillAppear中，d O此：

override func viewWillAppear(_ animated: Bool) { 
     super.viewWillAppear(animted) 
     view.layoutIfNeeded() 

     let redRocksPin = RedRocksPin(title: "Jerry Garcia 1/2/72", subtitle: "Red Rocks Amphitheatre", coordinate: redRocks) 
     mapView.addAnnotation(redRocksPin) 
    } 

然后将此：

override func viewDidAppear(_ animated: Bool) { 
     super.viewDidAppear(animated) 
     mapView.setRegion(MKCoordinateRegionMakeWithDistance(redRocks, distanceSpan, distanceSpan), animated: true) 
    } 

那么这样做是在你的viewWillAppear中，它将绘制的MapView，所以你可以添加注释，而不会导致系统崩溃，那么在viewdidar中，它只会放大您添加的注释。

不知道这是最好的方法，但要尝试。