Ios 如何在UIControl的子类上添加UIButton

我有一个子类

UIControl

我想要实现的是一个带有2个UIButton的

UISlider

，就像拇指一样

但我不知道我是否应该使用

触摸开始（：）

或

开始触摸（：）

我如何强制我的按钮跟随触摸事件 我所做的只是通过覆盖按钮的@highlighted属性来突出显示按钮，如下所示：

class RangeSliderThumbLayer: UIButton {
    override var highlighted: Bool {
        didSet {
            //print("did set \(highlighted)")
            setNeedsDisplay()
            if highlighted {
            self.backgroundColor = UIColor.redColor()
            } else {
            self.backgroundColor = UIColor.greenColor()
            }
        }
    }

下面是我如何尝试移动我的按钮：

 let lowerThumbButton = RangeSliderThumbLayer(frame: CGRect(x: 0, y: 0, width: 20, height: 20))
 let upperThumbButton = RangeSliderThumbLayer(frame: CGRect(x: 0, y: 0, width: 20, height: 20))

override func beginTrackingWithTouch(touch: UITouch, withEvent event: UIEvent?) -> Bool {
    previousLocation = touch.locationInView(self)
    print(previousLocation)
    lowerThumbButton.frame = CGRectMake(previousLocation.x, 0, 20, 20)
    // Hit test the thumb layers
    if lowerThumbButton.pointInside(previousLocation, withEvent: event)  {
        print("point indide")
        lowerThumbButton.highlighted = true
    } else if upperThumbButton.frame.contains(previousLocation) {
        upperThumbButton.highlighted = true
    }

    return lowerThumbButton.highlighted || upperThumbButton.highlighted
}

 private func boundValue(value: Double, toLowerValue lowerValue: Double, upperValue: Double) -> Double {
        return min(max(value, lowerValue), upperValue)
}

override func continueTrackingWithTouch(touch: UITouch, withEvent event: UIEvent?) -> Bool {
    let location = touch.locationInView(self)
    let value = round(location.x / step)
    let validValue = minimumValue + (Double(value) * increase)
    let deltaLocation = Double(location.x - previousLocation.x)
    print(value)
    lowerThumbButton.frame = CGRectMake(value, 0, 20, 20)
    previousLocation = location

    if lowerThumbButton.highlighted {
        lowerValue = boundValue(validValue, toLowerValue: minimumValue, upperValue: upperValue)
    } else if upperThumbButton.highlighted {
        upperValue = boundValue(validValue, toLowerValue: lowerValue, upperValue: maximumValue)
    }

    return true
}