ios - 在 Swift 中初始化 CLCircularRegion

Question

我是 iOS 编程的新手，正在自学如何使用 Swift。我需要为我为类(class)制作的应用程序设置地理围栏。我的问题是在初始化 CLCircularRegion 时我收到一条错误消息“Use of undeclared type 'center'”。我关注了 Apple 开发者网站上的文档，但不知道我做错了什么。任何帮助将不胜感激。谢谢。

import UIKit
import MapKit
import CoreLocation

class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {

@IBOutlet var mapView: MKMapView!

var manager = CLLocationManager()

@IBAction func startMonitoring(sender: AnyObject) {
    // 43.039278, -87.932479 mccormick hall location
    var latitude:CLLocationDegrees = 43.039278
    var longitude:CLLocationDegrees = -87.932479
    var center:CLLocationCoordinate2D = CLLocationCoordinate2DMake(latitude, longitude)
    var radius:CLLocationDistance = CLLocationDistance(10.0)
    var identifier:String = "vicmic"

    var geoRegion:CLCircularRegion = CLCircularRegion(center: center, radius: radius, identifier: identifier)

}


override func viewDidLoad() {
    super.viewDidLoad()

    // Core Location
    manager.delegate = self
    manager.desiredAccuracy = kCLLocationAccuracyBest
    manager.requestWhenInUseAuthorization()
    manager.startUpdatingLocation()

}

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


}

Answer 1

大体上......代码似乎没问题

1) 尝试在类型注释之前留空格，例如从 var center:CLLocationCoordinate2D 到这个 var center: CLLocationCoordinate2D 和

2) 尝试清理 DerivedData，重启 Xcode..