如何在带有滑块的滑块上添加UILabel？

Question

我有一个包含5个部分的滑块，我想逐步了解这些部分！而我做到了：

@IBAction func changeCostSlider(_ sender: UISlider) {
    sender.value = roundf(costSlider.value)
}

我也想在滑块的拇指上添加标签，我试图将此代码添加到上面的代码中：

let trackRect: CGRect  = costSlider.trackRect(forBounds: costSlider.bounds)
    let thumbRect: CGRect  = costSlider.thumbRect(forBounds: costSlider.bounds , trackRect: trackRect, value: costSlider.value)
    let x = thumbRect.origin.x + costSlider.frame.origin.x
    let y = costSlider.frame.origin.y - 20
    sliderLabel.center = CGPoint(x: x, y: y)

但是，当我移动滑块时，我的标签会从将其放置在情节提要中的位置跳出来，并且会有些滞后！有人对如何将此标签添加到我的步进滑块并正常工作有任何建议吗？

我认为我的问题是我将UILable固定在storyborad中，当我将拇指移到滑块中时，稍微移动了一秒钟，它又回到了固定位置！我该怎么解决？

我尝试以编程方式添加我的UILabel，直到我触摸拇指后，它才起作用！它是如何完成的：

var sliderLableP = UILabel()
@IBAction func changeCostSlider(_ sender: UISlider) {
    sender.value = roundf(costSlider.value)
    print(costSlider.value)
    let trackRect: CGRect  = costSlider.trackRect(forBounds: costSlider.bounds)
    let thumbRect: CGRect  = costSlider.thumbRect(forBounds: costSlider.bounds , trackRect: trackRect, value: costSlider.value)
    let x = thumbRect.origin.x + costSlider.frame.origin.x
    let y = costSlider.frame.origin.y - 20
    sliderLableP.center = CGPoint(x: x, y: y)
}

在我的viewDidLoad中，我添加了以下内容：

sliderLableP = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 20))
    let trackRect: CGRect  = costSlider.trackRect(forBounds: costSlider.bounds)
    let thumbRect: CGRect  = costSlider.thumbRect(forBounds: costSlider.bounds , trackRect: trackRect, value: costSlider.value)
    let x = thumbRect.origin.x + costSlider.frame.origin.x
    let y = costSlider.frame.origin.y - 20
    sliderLableP.center = CGPoint(x: x, y: y)
    sliderLableP.textAlignment = NSTextAlignment.center
    sliderLableP.textColor = UIColor.blue
    self.containerView.addSubview(sliderLableP)
    containerView.bringSubview(toFront: sliderLableP)

Answer 1

此解决方案适用于我：

@IBAction func changeCostSlider(_ sender: UISlider) {
    sender.value = roundf(sender.value)

    let trackRect = sender.trackRect(forBounds: sender.frame)
    let thumbRect = sender.thumbRect(forBounds: sender.bounds, trackRect: trackRect, value: sender.value)
    self.sliderLabel.center = CGPoint(x: thumbRect.midX, y: self.sliderLabel.center.y)
}