在另一个视图上更新标签 [英] Update Label On Another View

问题描述

我有两个视图，其中一个带有标签.在第二个视图上，有一个按钮.我在这里想要实现的是能够按下按钮，它会在第一个视图上更新标签.我怎么做?我无法从第二个视图访问IBOutlet.我需要对IBOutlet进行公开公开等吗?

I have two views with a label on one of them. On the second view, there is a button. What I want to achieve here is to be able to press the button and it updates the label on the first view. How do I do that? I can't access the IBOutlet from the second view. Is there something that I have to do to the IBOutlet to make it public etc?

推荐答案

您可以为此使用NSNotificationCenter.

首先在您的viewDidLoad方法中，将此代码添加到您的firstViewController类中:

First of all in your viewDidLoad method add this code in your firstViewController class:

NSNotificationCenter.defaultCenter().addObserver(self, selector: "refreshlbl:", name: "refresh", object: nil)

在您的应用加载时会显示addObserver.

which will addObserver when your app loads.

并在同一viewController中添加此帮助程序方法.

And add this helper method in same viewController.

func refreshlbl(notification: NSNotification) {

    lbl.text = "Updated by second View"  //Update your label here.
}

之后，在您关闭视图时，在secondViewController中添加以下代码:

After that in your secondViewController add this code when you dismiss your view:

@IBAction func back(sender: AnyObject) {
    NSNotificationCenter.defaultCenter().postNotificationName("refresh", object: nil, userInfo: nil)
    self.dismissViewControllerAnimated(true, completion: nil)
}

现在，当您从secondView按下返回按钮时，将从firstView调用refreshlbl方法.

Now when you press back button from secondView then refreshlbl method will call from firstView.

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