Question

这是我的设置：ViewController - ＆gt; SecondViewControoler

三个目标：

将图像添加到自定义注释（请参阅下面的代码）
我有一个名为“Capital”的子类，我想在＃1中添加图像，然后创建其他变量来保存将传递给包含（2）标签和Picker View的新SecondViewController的值：for示例label1 =“text1”，label2 =“text2”，然后从包含多个对象的数组中获取一个字符串（即Picker每行的标题）
一旦用户点击自定义引脚上的callout按钮，我们将ViewController推送到名为“SecondViewController”的新ViewController，并分配附加到自定义引脚的子类“Capital”的值，该引脚被点击到新标签和Second ViewController中的Picker视图

到目前为止，这是我的代码：

名为“Capital.swift”的子类

import MapKit
import UIKit

class Capital: NSObject, MKAnnotation {
    var title: String?
    var coordinate: CLLocationCoordinate2D
    var info: String

    // here we would add the custom image in Goal #1
    // here we would add the (2) values for label1 and label2 in Goal #2
    // here we would add the array that contains multiple object in Goal #2

    init(title: String, coordinate: CLLocationCoordinate2D, info: String) {
        self.title = title
        self.coordinate = coordinate
        self.info = info

     // add additional lines as needed

    }
}

这是我的ViewController.swift

import MapKit
import UIKit

class ViewController: UIViewController, MKMapViewDelegate {

    @IBOutlet var mapView: MKMapView!
    override func viewDidLoad() {
        super.viewDidLoad()

        let london = Capital(title: "London", coordinate: CLLocationCoordinate2D(latitude: 51.507222, longitude: -0.1275), info: "Home to the 2012 Summer Olympics.")
        let oslo = Capital(title: "Oslo", coordinate: CLLocationCoordinate2D(latitude: 59.95, longitude: 10.75), info: "Founded over a thousand years ago.")
        let paris = Capital(title: "Paris", coordinate: CLLocationCoordinate2D(latitude: 48.8567, longitude: 2.3508), info: "Often called the City of Light.")
        let rome = Capital(title: "Rome", coordinate: CLLocationCoordinate2D(latitude: 41.9, longitude: 12.5), info: "Has a whole country inside it.")
        let washington = Capital(title: "Washington DC", coordinate: CLLocationCoordinate2D(latitude: 38.895111, longitude: -77.036667), info: "Named after George himself.")

        mapView.addAnnotations([london, oslo, paris, rome, washington])
    }

    func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {

        let identifier = "Capital"
        if annotation is Capital {
            if let annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: identifier) {
                annotationView.annotation = annotation
                return annotationView
            } else {
                let annotationView = MKPinAnnotationView(annotation:annotation, reuseIdentifier:identifier)
                annotationView.isEnabled = true
                annotationView.canShowCallout = true

                let btn = UIButton(type: .detailDisclosure)
                annotationView.rightCalloutAccessoryView = btn
                //annotationView.image = UIImage(named: "#imageLiteral(resourceName: ",pin,")")
            return annotationView
         }
       }
        return nil
    }

在这里，我们添加特定于已按下的城市的自定义标注变量，并将这些变量推送到SecondViewController

func mapView(_ mapView: MKMapView, annotationView view: MKAnnotationView, calloutAccessoryControlTapped control: UIControl) {
        let capital = view.annotation as! Capital
        let placeName = capital.title
        let placeInfo = capital.info

        //Add custom image + (2) labels + and the array that contains multiple objects to be passed to the Picker 'view in the SecondViewController

        // Upon the User tapping the above button we push all the variables stored in Capital attached to the current city pin that was pressed to the new SecondViewController

        // Send the View Controller to the SecondViewController programically

        let SecondViewController = self.storyboard?.instantiateViewController(withIdentifier: "SecondViewController")
        self.show(SecondViewController!, sender: nil)       
    }
}

这是我的SecondViewController代码

import UIKit
class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
    @IBOutlet weak var pickerView: UIPickerView!
    var cityName = 0

//the values here are pulled from the custom pin that was pressed in the previous ViewController

var Array = ["object1 from custom pin","object2 from custom pin,","object3 from custom pin"]

@IBOutlet weak var label1: UILabel!
@IBOutlet weak var label2: UILabel!
override func viewDidLoad() {
    super.viewDidLoad()
    pickerView.delegate = self
    pickerView.dataSource = self
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    return Array[row]
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return Array.count
}

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
}

@IBAction func submit(_ sender: Any) {
    if (cityName == 0){
        label1.text = "object1 from custom pin"
    }
        else if(cityName == 1){
        label1.text = "object2 from custom pin"
    }
    else{
        label1.text = "object3 from custom pin"

续...

    }
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    cityName = row   
    }
}

感谢任何帮助

Answer 1

另一种选择是致电
```
"func performSegue(withIdentifier identifier: String, sender: Any?)"
```
将从ViewController触发segue SecondViewController。这就是你想在故事板中保持ViewControllers之间移动的代码，即你控制从ViewController拖到SecondViewController来创建一个segue并给它一个唯一的id。
每个UIViewController（子类）都继承了一个函数
```
"func prepare(for segue: UIStoryboardSegue, sender: Any?)"
```
将由系统调用，您可以在此处添加实施以顾名思义准备以前需要的东西执行特定的segue。这时候下一个 ViewController已从Storyboard加载到内存中（但是没有开始显示）。和＆＃34; segue＆＃34; *参数 "prepare(for segue: UIStoryboardSegue, sender: Any?)"实际上有一个 property ＆＃34; destination＆＃34; 实际上是下一个ViewController。

小心但是，因为你可能有超过1个segue ViewController到不同的下一个ViewController。
因此"segue.destination"可能不是您想要的SecondViewController 你有超过1个segue设置。因为系统调用每个"prepare(for segue: UIStoryboardSegue, sender: Any?)" segue离开这个当前的ViewController。一定要检查 "segue.identifier"以确保您的后续代码正在处理你认为自己就是一样的。
现在你终于可以做你头条问题了。使用指向SecondViewController的指针，您可以自由设置任何它拥有的财产，这是您的资本的特定实例宾语。要完整循环， ＆＃34;发件人＆＃34; 参数 "performSegue(withIdentifier identifier: String, sender: Any?)"*和 "prepare(for segue: UIStoryboardSegue, sender: Any?)"实际上是一样。所以你实际上可以传递你喜欢的任何对象/结构 ＆＃34; performSegue（）＆＃34; to＆＃34;准备（for：）＆＃34; 简单地将发件人对象转换为确认＆＃34; segue.identifier后通过的类型。＆＃34;

func mapView(_ mapView: MKMapView, annotationView view: MKAnnotationView, calloutAccessoryControlTapped control: UIControl) {
    let capital = view.annotation as! Capital 
    let placeName = capital.title 
    let placeInfo = capital.info 

    // Option 1 
    perform segue.performSegue(withIdentifier: "SegueToSecondID", sender: capital) 

    //Option 2 programmatically create SecondViewController and show. 
    let SecondViewController = self.storyboard?.instantiateViewController(withIdentifier: "SecondViewController") 
    SecondViewController.capital = capital 
    self.show(SecondViewController!, sender: nil)       
}

// If you are doing option 1
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "SegueToSecondID" && sender is Capital {
        let destination = segue.destination as SeconViewController
        destination.capital = sender
    }
}

class SecondViewController {
    //........
    var capital: Capital?  //Up to you if you want this as an optional

}

Answer 2

使用Rob的建议，但是将Capital对象传递给发件人而不是视图，calloutAccessoryControlTapped可能如下所示：

func mapView(_ mapView: MKMapView, annotationView view: MKAnnotationView, calloutAccessoryControlTapped control: UIControl) {
    guard let capital = view.annotation as? Capital else { return }
    performSegue(withIdentifier: "segue1", sender: capital)
}

func prepare(for segue: UIStoryboardSegue, 
      sender: Any?) {
    guard let destination = segue.destination as? SecondViewController,
        let capital = sender as? Capital else { return }
    destination.capital = capital //Assuming SecondViewController has a capital property
}

Answer 3

创建对要将数据传递到AKA目标类的类的引用

    `let vc = self.storyboard!.instantiateViewController(withIdentifier: "Class Identifier") as! YourDestinationClass`

然后，您可以使用YourDestinationClass

访问vc内的所有对象

如何通过Swift 3.0中的Segue从子类传递变量和对象

3 个答案: