更改变量并将其发送到第二个视图控制器

Question

我正在为我的游戏创建一个商店屏幕。例如，您可以在哪里购买角色。当在商店视图上按下按钮时，我需要一个变量来更改，然后将其发送到下一个视图控制器。然后，第二个视图控制器将根据变量的值选择正确的播放器，我为商店视图控制器提供以下代码：

import Foundation
import UIKit

class Shop: UIViewController {

    @IBAction func buttonPressed(_ sender: AnyObject){
        var x = 1
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if (segue.identifier == "segue") {
            let dest = segue.destination as! GameViewController
            dest.x = x
        }
    }
}

但是变量不是全局的，所以我该怎么做。任何建议将不胜感激。

Answer 1

根据您的要求，我认为全局 Singleton 对象是您的最佳选择。

全局单例允许您跨控制器访问商店数据。

例如

class ShopManager {
    static let sharedInstance = ShopManager()

    var x = 0 // some initial value

    private init() {} //Ensures singleton is unique
} 

现在您可以在任何地方获取/设置ShopManager.sharedInstance.x（或在单例类中声明的任何其他变量/对象），而无需在控制器之间传递数据。

import Foundation
import UIKit

class Shop: UIViewController {

    @IBAction func buttonPressed(_ sender: AnyObject){
        ShopManager.sharedInstance.x = 1
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if (segue.identifier == "segue") {
            let dest = segue.destination as! GameViewController
            //no need to set dest.x here. just access ShopManager.sharedInstance.x from the destination controller!
        }
    }
}

class ShopManager {
    static let sharedInstance = ShopManager()

    var x = 0 // some initial value

    private init() {} //Ensures singleton is unique
} 

Answer 2

1. 您可以将x作为变量存储在ShopViewController中：

var x: Int?

@IBAction func buttonPressed(_ sender: AnyObject){
    x = 1
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if (segue.identifier == "segueId") {
        let dest = segue.destination as! GameViewController
        dest.x = x
    }
}

1. 您可以add a segue from one controller to another 而不是一个确切的按钮，并从您的回调中执行它：

@IBAction func buttonPressed(_ sender: AnyObject){
    performSegue(withIdentifier: "segueId", sender: 1)
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if (segue.identifier == "segueId") {
        let dest = segue.destination as! GameViewController
        dest.x = sender as! Int
    }
}