Ios 如何在放大时显示地图注释？

我有一张地图，上面有很多注释，都钉在全国的地图上。现在我想在有人放大地图时自动显示注释。你知道怎么开始吗？现在我有几行代码：

注释类

地图视图类

---

有什么想法吗？

您可以通过调用

mapView以编程方式选择任何注释，或更靠近地图中心的注释。选择注释（注释，动画：true）

。但一次只能选择一个批注。

我会这样做：

extension  Double{

    func between( a:Double, b:Double) -> Bool{
        if self > a && self < b{
            return true
        }
        return false
    }

}


extension MapViewController : MKMapViewDelegate{

    //using special image for standard view for the annotation
    func mapView(mapView: MKMapView, viewForAnnotation annotation: MKAnnotation) -> MKAnnotationView? {
        var anView = mapView.dequeueReusableAnnotationViewWithIdentifier("wtg")
        if anView == nil {
            anView = MKAnnotationView(annotation: annotation, reuseIdentifier: "wtg")
            anView!.canShowCallout = true
            anView!.image = UIImage(named: "wtg")
        }
        else {
            anView!.annotation = annotation
        } 
        return anView
    }

    //if the region center is close to something, show the annotations
    func mapView(mapView: MKMapView, regionDidChangeAnimated animated: Bool) {
        let region = mapView.region
        if region.center.latitude.between(myLatA, b: mylatB) && region.center.longitude.between(myLonA, b: myLonB)
        {
            //Add extra anotations or do other stuff
        }
    }
}

双分机{
func-between（a:Double，b:Double）->Bool{
如果self>a&&selfMKAnnotationView{
var anView=mapView.dequeueReusableAnnotationViewWithIdentifier（“wtg”）
如果anView==nil{
anView=MKAnnotationView（注释：注释，重用标识符：“wtg”）
anView！.canShowCallout=true
anView！.image=UIImage（名为：“wtg”）
}
否则{
anView！.annotation=annotation
} 
返回视图
}
//如果区域中心靠近某个对象，则显示注释
func地图视图（地图视图：MKMapView，区域IDChangeAnimated:Bool）{
让region=mapView.region
if region.center.lation.between（myLatA，b:mylatB）和region.center.longitude.between（myLonA，b:myLonB）
{
//添加额外的涂鸦或做其他事情
}
}
}

苹果在这个问题上做得很好。您应该查看“显示多个注释对象”部分，并使用代理方法mapView:regionWillChangeAnimated:和mapView:regionDidChangeAnimated:方法

class MapViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {

/* OUTLETS */    

@IBOutlet weak var mapOutlet: MKMapView!
@IBOutlet weak var activityIndicator: UIActivityIndicatorView!

/* VARIABLES */

let lm = CLLocationManager()
var data = [[String:String]]()

override func viewDidLoad() {
    super.viewDidLoad()

    // pin's data is loaded from the server and added to `data`

} 

override func viewDidAppear(animated: Bool) {
         self.addAnnotationToTheMap()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func addAnnotationToTheMap(){

    for i in data{

        let latitude = Double(i["latitude"]!)
        let longtitude = Double(i["longitude"]!)

        let coordinates = CLLocationCoordinate2DMake(latitude!, longtitude!)

        let pinOnTheMap = myAnnotation(title: i["title"]!, subtitle: i["subtitle"]!, coordinates: coordinates)
        mapOutlet.addAnnotation(pinOnTheMap)
    }    
}
} // end of class

extension  Double{

    func between( a:Double, b:Double) -> Bool{
        if self > a && self < b{
            return true
        }
        return false
    }

}


extension MapViewController : MKMapViewDelegate{

    //using special image for standard view for the annotation
    func mapView(mapView: MKMapView, viewForAnnotation annotation: MKAnnotation) -> MKAnnotationView? {
        var anView = mapView.dequeueReusableAnnotationViewWithIdentifier("wtg")
        if anView == nil {
            anView = MKAnnotationView(annotation: annotation, reuseIdentifier: "wtg")
            anView!.canShowCallout = true
            anView!.image = UIImage(named: "wtg")
        }
        else {
            anView!.annotation = annotation
        } 
        return anView
    }

    //if the region center is close to something, show the annotations
    func mapView(mapView: MKMapView, regionDidChangeAnimated animated: Bool) {
        let region = mapView.region
        if region.center.latitude.between(myLatA, b: mylatB) && region.center.longitude.between(myLonA, b: myLonB)
        {
            //Add extra anotations or do other stuff
        }
    }
}