ios - 如何使用步进 slider 在 slider 拇指上添加 UILabel？

Question

我有一个包含 5 个部分的 slider ，我想跨过这些部分!我这样做了:

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

我还想在 slider 的拇指上添加一个标签，我尝试将这段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 slider 时，我的标签会从我在 Storyboard 中放置标签的位置跳转，并且有一些滞后!有人对如何将此标签添加到我的步进 slider 并正常工作有任何建议吗？!

我认为我的问题是我将我的 UILable 固定在 Storyboard中，当我在 slider 中移动拇指时，一毫秒后，它又回到了固定位置!我该如何解决？!

我尝试以编程方式添加我的 UILabel，但直到我触摸拇指时它才起作用!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 中添加了这个:

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

这个解决方案适合我:

@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)
}