为什么不调用 ViewForAnnotation？

Question

我知道这个问题已被问过多次，但所有答案似乎都与我的应用程序中发生的情况略有不同。

我的理解是，一旦 mapView 将其委托设置为显示它的 ViewController 并且在 mapView 滚动时将注释添加到地图，就会调用 viewForAnnotation 函数，以便它显示在 mapView 区域内。

目前我有一个主 viewController (mainVC) 包含一个 MKMapView (mapView) 这个viewController控制了四个不同的地图在mapView中显示。

func moveViews(sender:Int) {
    // This function handles which button on the Segmented Control was clicked and the loads the appropriate map into the mapView (passed as a para

    removeAnnotationsAndOverlays() // ~~~
    if sender == 0 {
        // First Map was selected
        let map1VC = map1VC()
        map1VC.loadMap1View(mapView)
        map1VC.centerMapOnLocation()
    }
    else if sender == 1 {
        // Second Map was selected
        let map2VC = map2VC()
        map2VC.loadMap2View(mapView)
    }
    else if sender == 2 {
        // Third Map was selected
        let map3VC = map3VC()
        map3VC.loadMap3View(mapView)
    }
    else if sender == 3 {
        // Fourth Map was selected
        let map4VC = map4VC()
        map4VC.loadMap4View(mapView)
    }
    else {
        // Load First Map as default
        let map1VC = map1VC()
        map1VC.loadMap1View(mapView)
        map1VC.centerMapOnLocation()
    }
}

有几个不同的 classes 控制每个不同地图的功能：

地图 1 - 显示从 plist 读取的 MKPolylines 和自定义注释（继承自 MKAnnotation）的组合 - 这很好用！
地图 2 - 显示从 plist 读取的多个 MKPolylines - 这很好用！
地图 3 - 显示从 plist 读取的多个 MKPolylines - 这很好用！
地图 4 - 应该显示几个自定义注释 - 这不起作用！

地图 4 的情况如下：

正在正确加载 MKMapView

var mapView: MKMapView = MKMapView() // declared as a global variable/object inside the map4VC()

// Initial function to set up Map
//      Think of this function as the "override func viewDidLoad() {}"
func loadMap4View(mV: MKMapView) {

// This connects the parameter passed (mV) and sets it as the delegate for the mapView used throughout this file
//      In other words, it allows the mapView on the MainVC to use all of the code in this file to handle different actions
mapView = mV
mapView.delegate = self

let initialLocation = CLLocation(latitude: 50.3603125, longitude: 2.794017)

// calculates the region you'll look at on the screen 
let coordinateRegion = MKCoordinateRegionMakeWithDistance(initialLocation.coordinate, regionRadius, regionRadius)

// sets the region of the map
mapView.setRegion(coordinateRegion, animated: true)


//addPins()  // This can use a custom function to load all of the Pins
//mapView.addAnnotations(coords.allLocations!) // This line also works to add all of the individual pins

mapView.addAnnotation(coords.allLocations![2]) // This adds one single Pin

}

将 mapView 的委托设置为当前 class (mapView.delegate = self)
它在适当的位置放大 (mapView.setRegion(coordinateRegion, animated: true))
class 从 plist 读取并（使用助手 class）构建自定义 MKAnnotations (CemAnno) 数组

位置存储在名为 allLocations 的 CemAnno 数组中：

var allLocations: [CemAnno]? = [] // This is declared in the helper class along with a bunch of other stuff that grabs all of the information from a plist

 class CemAnno: NSObject, MKAnnotation {

var coordinate: CLLocationCoordinate2D
var title: String?
var casualties: String?
var visitInfo: String?
var histInfo: String?
var region: String?


init(title: String, coordinate: CLLocationCoordinate2D, region: String, casualties: String, visitInfo: String, histInfo: String) {

self.coordinate = coordinate
self.title = title
self.region = region
self.casualties = casualties
self.visitInfo = visitInfo
self.histInfo = histInfo
}

}

// This builds an object inside the the map4VC() class called coords that holds all of the information collected from the plist
var coords = BuildCoordinates(filename: "Coordinate")

将其中的每一个添加到地图 (mapView.addAnnotations) 并将它们显示为图钉（它们正在显示） mapView.addAnnotation(coords.allLocations![2]) // 这添加了一个 Pin 注释（有效）但从不调用 viewForAnnotation 函数

这行得通，但是，我正在尝试自定义正在显示的注释，但从未调用 ViewForAnnotation 函数？？？？

// This function is NEVER called
func mapView(mapView: MKMapView, viewForAnnotation annotation: MKAnnotation) -> MKAnnotationView?
{
    // Define a reuse identifier. This is a string that will be used to ensure we reuse annotation views as much as possible.
    let identifier = "CemAnno"

    // Check whether the annotation we're creating a view for is one of our CemAnno objects.
    if annotation.isKindOfClass(CemAnno.self) {
        print("correct class")
        //let anno = annotation as! CustomAnnotation
        // Try to dequeue an annotation view from the map view's pool of unused views.
        var annotationView = mapView.dequeueReusableAnnotationViewWithIdentifier(identifier)

        if annotationView == nil {
            print("no reusable view")
            // If it isn't able to find a reusable view, create a new one using MKPinAnnotationView and sets its canShowCallout property to be true. This triggers the popup with the name.
            annotationView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: identifier)
            annotationView!.canShowCallout = true

            // Create a new UIButton using the built-in .Custom type. This is so we can add an image to the button.
            let btn = UIButton(type: .DetailDisclosure)
            //btn.setImage(anno.image, forState: .Normal)
            annotationView!.rightCalloutAccessoryView = btn
        } else {
            print("reusing a view")
            // If it can reuse a view, update that view to use a different annotation.
            annotationView!.annotation = annotation
        }

        return annotationView

    }

    // If the annotation isn't from a CustomClass, it must return nil so iOS uses a default view.
    return MKPinAnnotationView()
}

我已经尝试在地图的当前视图区域内添加图钉的位置，但从未触发 ViewForAnnotation。我已经尝试在地图的当前视图区域之外添加图钉的位置，但是 ViewForAnnotation 从未被触发 - 我认为这应该是有效的，并且当我 'scroll' 地图并且它出现时在应该触发该功能的当前视图区域内，但它没有（我应该注意到图钉正在显示并显示在地图上）。

这使得我无法自定义我想做的引脚。

我使用与 Map 1 相同的技术，它工作得很好，但出于某种原因，从未在 Map 4 中调用 ViewForAnnotation。

如有任何建议，我们将不胜感激！！

Answer 1

抱歉，我看不到您的视图控制器的声明 mainVC：您的控制器实现了 MKMapViewDelegate?

import MapKit

class mainVC: UIViewController, MKMapViewDelegate 
{
    ...
}

编辑 1： 还要检查是否在你的故事板上的视图控制器中，如果委托与你的控制器链接如下：

只需右键单击您的 mapView。

Answer 2

我不时遇到这个问题 time.And 我发现有时你需要像这样手动调用 showAnnotations:animated: :

mapView.showAnnotations(mapView.annotations, animated: true)

Answer 3

这是一个非常愚蠢的答案，但今天它咬了我两次所以在这里：检查你的 latitude/longitude。如果你交换了它们，你有一个无效的点，或者一个在海洋中间，所以视图将永远不会被请求，因为它很可能在你的可见矩形之外。

为什么不调用 ViewForAnnotation？

Why is ViewForAnnotation not called?

mkmapview

mkannotationview

ios

swift2