Question

我是应用程序开发的新手，我试图让用户位置出现在模拟器中，但我一直得到使用未解析的标识符错误。我已经查看了其他问题，这些问题对于他们自己的项目非常具体，并试图以类似的方式处理我自己的应用程序，但无济于事。任何帮助，赞成？这是我的代码，以及指向Xcode屏幕截图的链接。

import UIKit
import MapKit
import CoreLocation

class SecondViewController: UIViewController, CLLocationManagerDelegate {

    //Map
    @IBOutlet weak var map: MKMapView!

    let manager = CLLocationManager()
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
    {   let location = locations[0]

        let span:MKCoordinateSpan = MKCoordinateSpanMake(0.01, 0.01)

        let myLocation:CLLocationCoordinate2D = CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude)

        let region:MKCoordinateRegion = MKCoordinateRegionMake(myLocation, span)


        self.map.showsUserLocation = true

    }

    override func viewDidLoad()
    {
        super.viewDidLoad()
        manager.delegate = self
        manager.desiredAccuracy = kCLLocationAccuracyBest
        manager.requestWhenInUseAuthorization()
        manager.startUpdatingLocation()

        //This is where I get an error
         map.setRegion(region, animated: true)**
    }

Error: Use of unresolved identifier

Answer 1

您的let region:MKCoordinateRegion是委托方法中的 本地标识符 ：

func locationManager(_:didUpdateLocations) {...}

这就是 使用未解析的标识符 的原因。在整个课程中都可以访问此identifier，错误将会消失。喜欢：

class SecondViewController: UIViewController, CLLocationManagerDelegate {

    //Map
    @IBOutlet weak var map: MKMapView!
    var region = MKCoordinateRegion()
    .......
    .......
}

N.B：但是这不会让你在地图上看到任何东西。查看MapView的任何输出的最佳方法是将map.setRegion(region, animated: true)放入delegate方法中：

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    let location = locations.first
    let span = MKCoordinateSpanMake(0.01, 0.01)
    let myLocation = CLLocationCoordinate2DMake((location?.coordinate.latitude)!, (location?.coordinate.longitude)!)
    region = MKCoordinateRegionMake(myLocation, span)
    map.setRegion(region, animated: true)
}

Answer 2

在MKCoordinateRegion方法之前使用viewdidload实例您可以按照以下代码进行参考。

class Test: UIViewController {
    var region =  MKCoordinateRegion()

    override func viewDidLoad() {
        super.viewDidLoad()
         region = MKCoordinateRegionMake(myLocation, span)
    }
}

Answer 3

您收到错误是因为

viewDidLoad（） 区域变量的方法do not have access内的变量区域 viewDidLoad（）方法
```
    //This is where I get an error
    map.setRegion(region, animated: true)**
```

解决方案：

将区域变量全局设置为类，以便可以从任何您想要的位置访问它。

而不是 func locationManager

中的这一行

let region:MKCoordinateRegion = MKCoordinateRegionMake(myLocation,span)

使用

    self.region = MKCoordinateRegionMake(myLocation,span)

以下是您可以使用的完整代码。

import UIKit
import MapKit
import CoreLocation

class SecondViewController: UIViewController, CLLocationManagerDelegate {

    //Map
    @IBOutlet weak var map: MKMapView!
    //global variable 
    var region:MKCoordinateRegion = MKCoordinateRegion()

    let manager = CLLocationManager()
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
    {   let location = locations[0]

        let span:MKCoordinateSpan = MKCoordinateSpanMake(0.01, 0.01)

        let myLocation:CLLocationCoordinate2D = CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude)

        self.region = MKCoordinateRegionMake(myLocation, span)


        self.map.showsUserLocation = true

    }

    override func viewDidLoad()
    {
        super.viewDidLoad()
        manager.delegate = self
        manager.desiredAccuracy = kCLLocationAccuracyBest
        manager.requestWhenInUseAuthorization()
        manager.startUpdatingLocation()

        //This is where I get an error
         map.setRegion(region, animated: true)**
    }
//

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

更重要的是，如果您使用模拟器，则必须启用位置模拟。

用户位置不会出现在Xcode的模拟器中

3 个答案: