从其他ViewController调用函数 [英] Call function from other ViewController

问题描述

我有两个ViewControllers， FirstViewController 和 SecondViewController 。两者都有自己的Swift文件， FirstViewController.swift 和 SecondViewController.swift 。

I have two ViewControllers, FirstViewController and SecondViewController. Both have an own Swift file, FirstViewController.swift and SecondViewController.swift.

FirstViewController.swift 包含：

class FirstViewController: UIViewController {
    @IBAction func callFunctionInOtherClass(sender: AnyObject) {
//        Call "func showAlert" in SecondViewController when clicking the UIButton in FirstViewController
    }
}

SecondViewController.swift 包含：

class SecondViewController: UIViewController {

    @IBOutlet weak var textField: UITextField!

    func showAlert(sender: AnyObject) {
        let alert = UIAlertView(title: "Working!", message: "This function was called from FirstViewController!\nTextField says: \(textField.text!)", delegate: nil, cancelButtonTitle: "Okay")
        alert.show()
    }
}

我希望能够在 SecondViewController中调用 func showAlert（） 在 FirstViewController 中点击 UIButton 时。

I want to be able to call the func showAlert() in SecondViewController when taping on the UIButton in FirstViewController.

我已经花了很多个夜晚才找到解决方案但没有工作。有人知道该怎么做才能达到这个目标吗？

I've already spent many nights to find a solution but none worked. Does anybody know what to do to reach this goal?

我在这里上传了一个示例Xcode项目： CallFuntionInOtherClassX | filedropper.com

I uploaded a sample Xcode project here: CallFuntionInOtherClassX | filedropper.com

PS：当然，我可以发布一些代码并解释我得到的错误，但我认为这是不合理的，因为我真的不知道该怎么做。

推荐答案

你可以使用 NSNotificationCentre 完成此任务。

You may use NSNotificationCentre to accomplish this task.

在 viewDidLoad 的方法> SecondViewController 类注册self作为观察者来接收通知广播： -

In viewDidLoad method of your SecondViewController class register self as observer to receive notification broadcasts:-

override func viewDidLoad() {
    NotificationCenter.default.addObserver(self, selector: #selector(showAlert), name: NSNotification.Name(rawValue: "callForAlert"), object: nil)
}

并且在 FirstViewController 的按钮操作方法中，您应该通过以下方式触发通知： -

and in FirstViewController's button action method you should fire the notification by writing :-

@IBAction func callFunctionInOtherClass(sender: AnyObject) {
    //Call "func showAlert" in SecondViewController when clicking the UIButton in FirstViewController
    NotificationCenter.default.post(name: NSNotification.Name(rawValue: "callForAlert"), object: nil)
}

不要忘记在SecondViewController的 viewDidUnload removeObserver c>方法。

Don't forget to call removeObserver in SecondViewController's viewDidUnload method.

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