Swift 从不同的ViewController更改UIButton

我需要从另一个

UIViewController

我试过下面的方法

import UIKit

class ViewController: UIViewController{

    @IBOutlet var B1: UIButton!
    @IBOutlet var B2: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
    }


}

输出为：

c:  V1B1
c:  a

B1O:  V1B1
B1:  Optional("V1B1")
B1:  Optional("a")

它改变了（正如输出所说）！但是当视图被取消时，它会返回到“V1B1”，这是我放在

Main.storyboard

我还试图通过协议和委托来改变它

import UIKit

class ViewController: UIViewController,TestDelegate {
    func t(NewT: UIButton) {
        NewT.setTitle("a", for: .normal)
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let dd = segue.destination as? View2 {
            dd.d = self
            print("B1O: ",B1.currentTitle!)
        }
    }

    @IBOutlet var B1: UIButton!
    @IBOutlet var B2: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

输出：

c:  V1B1
c:  a

B1O:  V1B1
B1:  Optional("V1B1")
B1:  Optional("a")

代码有什么问题？

即使再次加载

UIViewController

，“它已更改（如输出所述）！但当视图取消时，它会返回到“V1B1”，这是我放在Main.storyboard中的标题。”

您在新的V1实例中更改了B1的标题，而不是在现有的V1实例中

不要在Disclose方法中为ViewController类创建新实例

class ViewController: UIViewController,TestDelegate {
    func change(text: String) {
        B1.setTitle(text, for: .normal)
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let dd = segue.destination as? View2 {
            dd.d = self
            print("B1O: ",B1.currentTitle!)
        }
    }

    @IBOutlet var B1: UIButton!
    @IBOutlet var B2: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}
protocol TestDelegate {
    func change(text: String)
}

class View2: UIViewController {
    var d: TestDelegate?

    @IBAction func Dismiss(_ sender: Any) {
        d?.change(text:"NewTitle")
        dismiss(animated: true, completion: nil)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

非常感谢“RajeshKumar R”和“Bhavesh Nayi”

---

每次按钮都会不同，这就是为什么我认为协议应该是UIButton而不是字符串，我只使用了两个类来解释这个问题，但项目要大得多。@其中一个是否有两个或更多的按钮？另外，如果你能解释我的代码基本上出了什么问题，请谅解，该项目是一个游戏，按钮是关卡，一旦用户完成一个关卡，下一关卡将为他提供“isEnabled=true”@其中一个首先您有一个ViewController类的实例，让我们将其命名为a。然后对View2的一个实例执行segue，我们将其命名为b。现在，当你解雇b时，你回到a。但是您正在为类ViewController创建一个新实例c。如果在c中更改按钮的标题，则不会在a中更改标题

import UIKit

class ViewController: UIViewController{

    @IBOutlet var B1: UIButton!
    @IBOutlet var B2: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    open override func viewWillAppear(_ animated: Bool) {
        // Register to receive notification
        NotificationCenter.default.addObserver(self, selector: #selector(self.updateTitle), name: NSNotification.Name(rawValue: "buttonTitleUpdate"), object: nil)
        super.viewWillAppear(animated)
    }

    @objc func updateTitle() -> Void {
        print("c: ",B1.currentTitle ?? "")
        B1.setTitle("a", for: .normal)
        print("c: ",B1.currentTitle ?? "")
    }

}


import Foundation
import UIKit

class View2: UIViewController {
    @IBAction func Dismiss(_ sender: Any) {

        // Post a notification
        NotificationCenter.default.post(name: NSNotification.Name(rawValue: "buttonTitleUpdate"), object: nil)

        dismiss(animated: true, completion: nil)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

import UIKit

class ViewController: UIViewController,TestDelegate {
    func t(NewT: Int) {
    let TempButton = self.view.viewWithTag(NewT) as! UIButton
        TempButton.setTitle("X", for: .normal)
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if let dd = segue.destination as? View2 {
            dd.d = self
        }
    }


    @IBOutlet var B1: UIButton!
    @IBOutlet var B2: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

import Foundation
import UIKit

protocol TestDelegate {
    func t(NewT: Int)
}

class View2: UIViewController {
var d: TestDelegate?

    @IBAction func Dismiss(_ sender: Any) {
        //just pass the tag
            d?.t(NewT: 1)
        dismiss(animated: true, completion: nil)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}