iOS-视图控制器响应uiview中的数据更改

Question

我在我的视图控制器中使用了一个由其他人编写的颜色选择器（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，它会被更新。

public class SwiftHSVColorPicker: UIView {
    var colorWheel: ColorWheel!
    ...
    public var color: UIColor!
    ...
}

请参阅：https://github.com/johankasperi/SwiftHSVColorPicker/blob/master/Source/SwiftHSVColorPicker.swift

我已经在我的视图控制器中引用了这个颜色选择器视图和一个标签：

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

每当颜色选择器视图中的"颜色"数据发生更改时，如何更新标签文本？

Answer 1

如果可能，您需要修改它有两种方法：

1.

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
}   

2.

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
    }
}