Swift:确定按钮标题是否已更改 [英] Swift: Determine if the buttons title was changed

问题描述

我是 swift 的新手，请多多包涵.

Im a newbie in swift, please bear with me.

我有按钮-A，当点击它时会显示一个弹出框，弹出框有一个文本字段和一个确认按钮.当点击确认时，文本字段上的任何值都将用于更改按钮-A 标题.

I have button-A that when clicked show a popover, the popover has a text field and a confirm button. when the confirm is clicked, any value on the text field will be used to change the button-A title.

我的问题是，我们如何监控按钮标题是否已更改?显然，我们可以直观地看到它，但我的目标是以编程方式进行.

My question is, how can we monitor if the button title was changed? Obviously We can see it visually but my goal is to do it programatically.

想法?

推荐答案

这里的一个例子可能会有所帮助.如果按钮名称为 myButton，我可以通过以下方式观察这些属性:

An example might help a little here. If a button name myButton I can observe those attributes with:

let options = NSKeyValueObservingOptions([.New, .Old, .Initial, .Prior])

self.addObserver(self, forKeyPath: "myButton.titleLabel.text", options: options, context: nil)

//对这些属性的更改将触发对以下内容的调用:

// Changes to these properties will trigger a call to:

override func observeValueForKeyPath(keyPath: String!,
    ofObject object: AnyObject!,
    change: NSDictionary!,
    context: CMutableVoidPointer) {

        println("CHANGE OBSERVED: \(change)")
}

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