Objective c UISlider拇指上的UILabel

如何将UILabel放置在UISlider的拇指上…这样当我移动拇指时…UILabel也会移动…因为它位于拇指上

有什么想法吗？

这个“旋钮”在公共API中是不可用的，所以连接它的机会很小-如果它是一个子视图而不是直接绘制的话

因此，您应该将标签添加到与滑块相同的视图中（确保稍后添加标签，使其显示在其上方）。然后，您可以侦听值更改事件，并相应地放置标签。首先，您需要了解端点之间的线性缩放，但这应该不会太困难

使用代码编辑：

yourLabel = [[UILabel alloc]initWithFrame:....];
// .. configure label
[[yourSlider superview] addSubview:yourLabel];
[yourSlider addTarget:self action:@selector(adjustLabelForSlider:) forControlEvents:UIControlEventValueChanged];


-(void)adjustLabelForSlider:(id)slider
{
    float value = slider.value;
    float min = slider.minimumValue;
    float max = slider.maximumValue;

    CGFloat newX = ...; // Calculate based on yourSlider.frame and value, min, and max
    CGFloat newY = ...;

    [yourLabel setCenter:CGPointMake(newX,newY)];
}

---

注：未测试代码；-）

这可能非常有帮助。。。 试试这个

yourLabel = [[UILabel alloc]initWithFrame:....];

//Call this method on Slider value change event

-(void)sliderValueChanged{
    CGRect trackRect = [self.slider trackRectForBounds:self.slider.bounds];
    CGRect thumbRect = [self.slider thumbRectForBounds:self.slider.bounds
                               trackRect:trackRect
                                   value:self.slider.value];

    yourLabel.center = CGPointMake(thumbRect.origin.x + self.slider.frame.origin.x,  self.slider.frame.origin.y - 20);
}

---

我可以通过使用这个片段获得最准确的值

只需在滑块的拇指上添加imageview即可在imageview上添加标签

- (IBAction)valueChangedSlider:(id)sender {
handleView = [_slider.subviews lastObject];
label = [[UILabel alloc] initWithFrame:handleView.bounds];
label = (UILabel*)[handleView viewWithTag:1000];

if (label==nil) {

    label = [[UILabel alloc] initWithFrame:handleView.bounds];

    label.tag = 1000;

    [label setFont:[UIFont systemFontOfSize:12]];
    label.textColor = [UIColor redColor];
    label.backgroundColor = [UIColor clearColor];

    label.textAlignment = NSTextAlignmentCenter;

    [handleView addSubview:label];


}
label.text = [NSString stringWithFormat:@"%0.2f", self.slider.value];

---

}与迅捷3的答案相同：

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

---

+1在视图顶部设置移动标签。您可以为自定义位置调整lbl.center.y。谢谢您的回答，此行必须是：yourlab.center=CGPointMake（thumbRect.origin.x+self.slider.frame.origin.x+yourlab.frame.size.width/2.f，self.slider.frame.origin.y-20）；谢谢你的贡献，但下次可能会添加一些文字。

extension UIImage {
    class func imageWithLabel(_ label: UILabel) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(label.bounds.size, false, 0)
        defer { UIGraphicsEndImageContext() }
        label.layer.render(in: UIGraphicsGetCurrentContext()!)
        return UIGraphicsGetImageFromCurrentImageContext() ?? UIImage()
    }
}

class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate, UITextFieldDelegate, UITextViewDelegate, UIPickerViewDelegate, UIPickerViewDataSource, UIScrollViewDelegate
{

    func maskRoundedImage(image: UIImage, radius: CGFloat) -> UIImage {
           let imageView: UIImageView = UIImageView(image: image)
           let layer = imageView.layer
           layer.masksToBounds = true
           layer.cornerRadius = radius
           UIGraphicsBeginImageContext(imageView.bounds.size)
           layer.render(in: UIGraphicsGetCurrentContext()!)
           let roundedImage = UIGraphicsGetImageFromCurrentImageContext()
           UIGraphicsEndImageContext()
           return roundedImage!
    }
    
    override func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()

            let label = UILabel(frame: CGRect(x: 0, y: 0, width: 28, height: 28))
            label.backgroundColor = .black
            label.textAlignment = .center
            label.font =  label.font.withSize(12)
            label.text = String(Int(round( backlightSlider.value * 100 )))
            label.textColor = .white
            var image = UIImage.imageWithLabel(label)
            image = maskRoundedImage(image: image, radius: 14.0)
            backlightSlider.setThumbImage(image, for: .normal)
}