Ios 如何正确地从pickerView切换到MapKitView

敬礼

在我的主ViewController中有一个pickerView，在我的ViewController中有两个单独的mapKitView。我的问题是，当我试图通过单击我的按钮进行分段时，我的应用程序崩溃并抛出异常。这只是一个例外，当然不会给我太多

我处理segue的方法是，我通过手动将一个从VC1拖动到VC2来创建一个，并给它一个“viewMapSegue”标识符，然后我也给我的按钮一个标签1，因为这是我以前做的一个练习，我认为通过这种方式，我可以确保将值设置为segue时所需的值，而不是之后所需的值

尽管如此，我仍不确定我犯了什么错误。我知道，如果我单独使用VC2代码和一些硬编码的lat/long值，它运行良好，并显示我输入的位置。代码如下：

城市数据：

import Foundation

class CityData {
    var cityName:String;
    var cityHighLight:String;
    var cityLat:Double;
    var cityLong:Double;

    init(cityName: String, cityHighLight:String, cityLat:Double, cityLong:Double) {
        self.cityName = cityName;
        self.cityHighLight = cityHighLight;
        self.cityLat = cityLat;
        self.cityLong = cityLong;
    }
}

VC1：

最后是地图视图所在的VC2：

//  ViewControllerTwo.swift
import UIKit
import MapKit

class ViewControllerTwo: UIViewController {

    var latChosen : Double = 0.0;
    var longChosen : Double = 0.0;


    @IBOutlet var myMap: MKMapView!

    override func viewDidLoad() {
        super.viewDidLoad()
        myMap.mapType = MKMapType.satellite;
        let initialLocation = CLLocation(latitude: latChosen, longitude: longChosen);
        let regionRadius: CLLocationDistance = 1000;

        func centerMapOnLocation(location : CLLocation) {
            let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate, regionRadius, regionRadius);
            myMap.setRegion(coordinateRegion, animated: true);
        }

        centerMapOnLocation(location: initialLocation);


    }



    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()

    }


    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}

---

哇……我真不敢相信我没有想到要早点检查一下。所以很明显，我的按钮有两个链接，一个插座连接正常，另一个来自上帝知道的地方。哇

你知道，苹果真的应该发出警告，比如“嘿，检查你的链接，兄弟”。无声的错误会让人发疯

//  ViewControllerTwo.swift
import UIKit
import MapKit

class ViewControllerTwo: UIViewController {

    var latChosen : Double = 0.0;
    var longChosen : Double = 0.0;


    @IBOutlet var myMap: MKMapView!

    override func viewDidLoad() {
        super.viewDidLoad()
        myMap.mapType = MKMapType.satellite;
        let initialLocation = CLLocation(latitude: latChosen, longitude: longChosen);
        let regionRadius: CLLocationDistance = 1000;

        func centerMapOnLocation(location : CLLocation) {
            let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate, regionRadius, regionRadius);
            myMap.setRegion(coordinateRegion, animated: true);
        }

        centerMapOnLocation(location: initialLocation);


    }



    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()

    }


    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}