通过带有加法和减法计数器的视图控制器传递整数值[重复]

Posted 2023-02-23

【中文标题】通过带有加法和减法计数器的视图控制器传递整数值[重复]

【英文标题】：Passing an integer value through view controllers with an addition and subtraction counter [duplicate]

【发布时间】：2020-07-21 21:44:15

【问题描述】：

我正在开发一款 Magic the Gathering Counter 应用程序。对于我的应用，我想点击twentyLife()、thirtyLife() 或fourtyLife() 来更改另一个视图控制器（即FifthViewController）中的变量值。

第二个视图控制器代码：

import UIKit


class SecondViewController: UIViewController 
    var vcFive = FifthViewController()

override func viewDidLoad() 
    super.viewDidLoad()

    // Do any additional setup after loading the view.

@IBAction func twentyLife() 
    vcFive.lifePoints.text = String(20)
    

@IBAction func thirtyLife() 
    vcFive.lifePoints.text = String(20)
    


@IBAction func fortyLife() 
    vcFive.lifePoints.text = String(20)

我尝试调用 FifthViewController 作为变量来更改我的生活点文本，但它不起作用。

这是我的第五个视图控制器的代码：

import UIKit

class FifthViewController: UIViewController 
    @IBOutlet weak var lifePoints: UILabel!
    var counter = 0
    

override func viewDidLoad() 
    super.viewDidLoad()

    // Do any additional setup after loading the view.


@IBAction func lifeUp() 

    counter += 1
    lifePoints.text = String(counter)


@IBAction func lifeDown() 
    counter -= 1
    lifePoints.text = String(counter)

任何帮助将不胜感激。这是我一直在尝试从头开始开发的第一个应用程序

【参考方案1】：

您应该在SecondViewController 上创建FifthViewController 的实例，并在FifthViewController 上创建一个变量，您可以在其中保存传递的数据。像这样：

SecondViewController

import UIKit


class SecondViewController: UIViewController 
    
    let fifthVC = self.storyboard?.instantiateViewController(withIdentifier: "fifthVC") as? FifthViewController

    override func viewDidLoad() 
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    

    @IBAction func twentyLife() 
        fifthVC.lifePointsInt = 20

    

    @IBAction func thirtyLife() 
        fifthVC.lifePointsInt = 30

    

    @IBAction func fortyLife() 
        fifthVC.lifePointsInt = 50
    

FifthViewController

import UIKit

class FifthViewController: UIViewController 
    var lifePointsInt = Int()
    @IBOutlet weak var lifePoints: UILabel!


    override func viewDidLoad() 
        super.viewDidLoad()

        lifePoints.text = "\(lifePointsInt)"
    

    @IBAction func lifeUp() 
        lifePoints.text = "\(lifePointsInt + 1)"
    

    @IBAction func lifeDown() 
        lifePoints.text = "\(lifePointsInt - 1)"
    

记得在你的 FifthViewController 的情节提要中输入你的情节提要 ID 为 "fifthVC" 如果在你的 SecondViewController 中选择你的生命计数后，你的传递到你的 FifthViewController，你可以在末尾添加 self.navigationController?.pushViewController(fifthVC!, animated: true)每个功能。

【讨论】：

谢谢。我现在在我的第二个视图控制器上收到此错误。代码：'(SecondViewController) -> () -> SecondViewController' 类型的值没有成员'storyboard'

那是在特定的代码行上吗？故事板上的 SecondViewController 是否与 Swift 文件相关联？