Question

我正在尝试使用Swift中的Map Kit。我尝试在地图上显示区域，一些引脚（MKPointAnnotation）和当前位置。我决定扩展MKPointAnnotation类 - 添加一个类别。

Class MyAnnotation.swift：

import UIKit
import MapKit

class MyAnnotation: MKPointAnnotation {
var category = Int() 
}

我创建了一个元组数组来存储有关对象的信息。在循环中，我处理该数组的所有元素，并从中生成一个数组MyAnnotation。然后，我尝试使用addAnnotations显示整个数组MyAnnotation。但只显示数组的最后一个元素....

import UIKit
import MapKit
import CoreLocation

class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {

@IBOutlet weak var mainMapView: MKMapView!

var locationManager = CLLocationManager()

var oneAnnotation = MyAnnotation()
var annotationArray = [MyAnnotation]()

var allObjectsTupleArray: [(objLat: CLLocationDegrees, objLong: CLLocationDegrees, objName: String, objDesc: String, objCat: Int)] = 
[(objLat: 53.204526, objLong: 50.111751, objName: "St. George's Church", objDesc: "Church of the Great Martyr St. George", objCat: 1), 
(objLat: 53.19364, objLong: 50.096599, objName: "Heart of Jesus Church", objDesc: "The Roman Catholic Church. Parish of the Sacred Heart of Jesus", objCat: 1), 
(objLat: 53.238906, objLong: 50.183754, objName: "Spiridonievsky Church", objDesc: "Parish of St. Spyridon the Wonderworker", objCat: 1), 
(objLat: 53.248509, objLong: 50.199976, objName: "St. John the Forerunner Church", objDesc: "Parish of of the Prophet and Forerunner St. John", objCat: 1), 
(objLat: 53.231875, objLong: 50.244071, objName: "The Resurrection Cathedral", objDesc: "The Resurrection Cathedral", objCat: 1)]

override func viewDidLoad() {
    super.viewDidLoad()

    locationManager.delegate = self
    locationManager.desiredAccuracy = kCLLocationAccuracyBest
    locationManager.requestAlwaysAuthorization()
    locationManager.startUpdatingLocation()

    var currentLatitude = 53.2393
    var currentLongitude =  50.18145

    var latDelta = 0.05
    var longDelta = 0.05

    var currentLocationSpan: MKCoordinateSpan = MKCoordinateSpanMake(latDelta, longDelta)
    var currentLocation: CLLocationCoordinate2D = CLLocationCoordinate2DMake(currentLatitude, currentLongitude)
    var currentRegion: MKCoordinateRegion = MKCoordinateRegionMake(currentLocation, currentLocationSpan)
    self.mainMapView.setRegion(currentRegion, animated: true)

    for oneObject in allObjectsTupleArray {

        var oneObjLoc: CLLocationCoordinate2D = CLLocationCoordinate2DMake(oneObject.objLat, oneObject.objLong)
        println("Latitude: \(oneObject.objLat)  Longitude: \(oneObject.objLong)")
        oneAnnotation.coordinate = oneObjLoc

        oneAnnotation.title = oneObject.objName
        println("ObjectName: \(oneObject.objName)")

        oneAnnotation.subtitle = oneObject.objDesc
        println("ObjectDescription: \(oneObject.objDesc)")

        oneAnnotation.category = oneObject.objCat
        println("Category: \(oneObject.objCat)")

        annotationArray.append(oneAnnotation)
    }

    self.mainMapView.addAnnotations(annotationArray)
}
}

我在self.mainMapView.addAnnotations(annotationArray)之前插入检查数组annotationArray的内容：

for testVar in annotationArray {
        println("Title of annotation: \(testVar.title)")
}

此检查始终显示相同的标题 - 最后一个！为什么表达式annotationArray.append(oneAnnotation)填充最后一个值的数组？在Xcode 6 Beta 5中，对于数组... {/ 1>已弃用+=

我做错了什么？

Answer 1

您只有一个MyAnnotation类的实例，因此您总是将相同的对象追加到数组中。

您必须在每次循环迭代中创建类的新实例。

for oneObject in allObjectsTupleArray {
    let oneAnnotation = MyAnnotation()
    ...
}

Swift中的MapKit，第3部分 - MKPointAnnotation，addAnnotations

1 个答案: