iOS-视图控制器响应uiview中的数据更改

我在别人编写的视图控制器中使用了一个颜色选择器（UIView子类），它包含几个处理触摸事件的子视图。颜色选择器有一个公共变量“color”，当用户与子视图交互时，它会更新

public class SwiftHSVColorPicker: UIView {
    var colorWheel: ColorWheel!
    ...

    public var color: UIColor!
    ...
}

见：

我在视图控制器中引用了此颜色选择器视图和标签：

@IBOutlet weak var colorPicker: SwiftHSVColorPicker!
@IBOutlet weak var output: UILabel!

---

当“颜色”数据从颜色选择器视图更改时，如何更新标签文本 有两种方法：

一,

二,

动态公共变量颜色：UIColor！//添加动态关键字
colorPicker.addObserver（self，forKeyPath:“color”，选项：[.Initial，.New]，context:nil）//为颜色添加观察者
重写func observeValueForKeyPath（键路径：String？，对象对象的类型：AnyObject？，更改：[String:AnyObject]？，上下文：UnsafeMutablePointer）{
//对颜色做点什么
如果让颜色=更改！[NSKeyValueChangeNewKey]为？UIColor{
self.label.textColor=颜色
}
}

谢谢你的回答，它就像一个符咒！我只是在Android中找不到与回调/侦听器等效的iOS。。。

var colorChanged : ((UIColor!)->())?// add a callback for the colorpicker

func hueAndSaturationSelected(hue: CGFloat, saturation: CGFloat) {
    self.hue = hue
    self.saturation = saturation
    self.color = UIColor(hue: self.hue, saturation: self.saturation, brightness: self.brightness, alpha: 1.0)
    brightnessView.setViewColor(self.color)

    self.colorChanged?(self.color) //call it at this method

    selectedColorView.setViewColor(self.color)
}

colorPicker.colorChanged = {[weak self]  color in

        self?.label.textColor = color //do something with your label

}   

dynamic public var color: UIColor! // add the dynamic keyword
colorPicker.addObserver(self, forKeyPath: "color", options:[.Initial, .New], context: nil) // add an observer for the color 


override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {
    //do something with the color
    if let color = change![NSKeyValueChangeNewKey] as? UIColor {
        self.label.textColor = color
    }

}