区域更改后，Swift注释无法正确显示

Question

我有以下函数来确定文本字段（searchAddress）中包含的地址的纬度/经度，以创建以此位置为中心的地图区域，然后首先为此位置添加注释，其次对于存储在Parse后端中的商店位置。

首次打开map view时，预设searchAddress文本字段，其中包含用户默认地址以及viewDidLoad对该功能的初始调用。它按照我的意图工作。但是，用户可以在此字段中键入不同的地址，然后单击“搜索”按钮，然后第二次调用相同的功能。它偶尔会起作用，但通常不会显示注释。

如果我再次单击“搜索”以使区域不会更改，则会正确显示注释。我认为这是一个计时问题，并且与我在更改区域时重绘地图所需的时间有关，因为有时注释会在第一次出现，但大多数时候却没有。如果我重复搜索而不更改地址，它可以正常工作。在此先感谢，我一直坚持这一点，无法找到解决方案。这是代码：

func addMapAnotations () {
        // var searchLocation = preferredDeliveryLocation.text
        var geocoder = CLGeocoder()
        var address = CLLocationCoordinate2D()
        geocoder.geocodeAddressString(searchAddress.text, completionHandler: {
            (placemarks: [AnyObject]!, error: NSError!) -> Void in
            if let placemark = placemarks?[0] as? CLPlacemark {
                var latDelta: CLLocationDegrees = 0.1
                var lonDelta: CLLocationDegrees = 0.1
                var span: MKCoordinateSpan = MKCoordinateSpanMake(latDelta, lonDelta)
                address = placemark.location.coordinate
                println(placemark.location.coordinate.latitude)
                println("Inside geocoder lititude: \(address.latitude)")
                println("Inside geocoder longitude: \(address.longitude)")
                var location: CLLocationCoordinate2D = CLLocationCoordinate2DMake(address.latitude, address.longitude)
                var region: MKCoordinateRegion = MKCoordinateRegionMake(location, span)
                self.map.setRegion(region, animated: true)

                var tempLocationObject = self.currentUser
                var searchAnnotation = NewCustomPointAnnotation(coordinate: address, title: "", subtitle: "", locationObject: tempLocationObject!, locationCategory: "")
                self.annotationCategory = "homeLocation"
                searchAnnotation.locationCategory = "homeLocation"
                searchAnnotation.coordinate = address
                searchAnnotation.title = "Search address"
                searchAnnotation.subtitle = "Search for delivery locations near by..."
                // self.map.addAnnotation(MKPlacemark(placemark: placemark))
                self.map.addAnnotation(searchAnnotation)
            }
        })

        self.queryCurrent.whereKey("country", equalTo: "Australia")
        // self.queryCurrent.whereKey("State", equalTo: state)
        self.queryCurrent.findObjectsInBackgroundWithBlock {
            (objects: [AnyObject]?, error: NSError?) -> Void in
            if error == nil {
                if let objects = objects as? [PFObject] {
                    for object in objects {
                        println(object.objectId)
                        var latitude = object["latitude"] as! CLLocationDegrees
                        var longitude = object["longitude"] as! CLLocationDegrees
                        var location: CLLocationCoordinate2D = CLLocationCoordinate2DMake(latitude, longitude)
                        var deliveryAnnotation = NewCustomPointAnnotation(coordinate: location, title: "", subtitle: "", locationObject: object, locationCategory: "")
                        self.annotationCategory = "deliveryLocation"
                        deliveryAnnotation.locationCategory = "deliveryLocation"
                        deliveryAnnotation.coordinate = location
                        deliveryAnnotation.title = object["name"] as! String
                        deliveryAnnotation.subtitle = "Click to select this location"
                        deliveryAnnotation.locationObject = object
                        println("Annotation 1: \(deliveryAnnotation.description)")
                        println("Object ID: \(deliveryAnnotation.locationObject.objectId)")
                        self.map.addAnnotation(deliveryAnnotation)
                    }
                }

            } else {
                println("No locations found")
            }
        }
    }