Question

我知道这个问题已被多次询问，但所有答案似乎与我的应用程序中的内容略有不同。

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

目前我有一个主viewController（mainVC），其中包含一个MKMapView（ mapView ）此viewController控制在mapView中显示的四个不同的地图。

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()
    }
}

有几个不同的类可以控制每个不同地图的功能：

地图1 - 显示从plist中读取的MKPolylines和自定义注释（继承自MKAnnotation）的组合 - 这非常有效！
地图2 - 显示从plist中读取的几个MKPolylines - 这非常有效！
地图3 - 显示从plist中读取的几个MKPolylines - 这非常有效！
地图4 - 应显示多个自定义注释 - 这不起作用！

以下是Map 4发生的事情：

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的委托设置为当前类（mapView.delegate = self）
放大适当的位置（mapView.setRegion（coordinateRegion，animated：true））
该类从plist读取并（使用帮助器类）构建一个自定义MKAnnotations数组（CemAnno）

这些位置存储在名为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），它们显示为引脚（它们正在显示） mapView.addAnnotation（coords.allLocations！[2]）//这会添加一个Pin Annotation（可以工作），但从不调用viewForAnnotation函数

然而，这是有效的，我尝试自定义正在显示的注释，但从不调用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()
}

我尝试在地图的当前视图区域内添加引脚的位置，但从不触发ViewForAnnotation。我已经尝试在地图的当前视图区域之外添加引脚的位置，但ViewForAnnotation永远不会被触发 - 我认为这应该是有效的，并且我滚动＆＃39;地图并显示在应该触发该功能的当前视图区域内，但它没有（我应该注意到该引脚正在显示并显示在地图上）。

这使得我无法自定义我想要的引脚。

我使用与Map 1完全相同的技术，但由于某种原因，ViewForAnnotation永远不会在Map 4中调用。

任何建议都将不胜感激!!

Answer 1

我经常遇到这个问题。我发现有时你需要像这样手动调用showAnnotations:animated:：

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

Answer 2

很抱歉，我看不到您的视图控制器声明 mainVC ：您的控制器是否实现了MKMapViewDelegate？

import MapKit

class mainVC: UIViewController, MKMapViewDelegate 
{
    ...
}

编辑1：还要检查故事板上的视图控制器中是否有代理人与您的控制器链接，如下所示：

右键单击mapView。

Answer 3

这是一个非常愚蠢的答案，但是今天对我造成了两次困扰，所以这里是：检查您的纬度/经度。如果交换了它们，那么您将有一个无效的点，或者是在海洋中央的一个点，因此将永远不会请求该视图，因为它可能在您的可见区域之外。

为什么不调用ViewForAnnotation？

3 个答案: