ios - UISlider 扭曲圆角

Question

我创建了一个 UISlider，然后为最小轨道设置色调颜色，如下所示:

    [slider setMinimumTrackTintColor:[UIColor whiteColor]];

但是，我最终会在左侧出现这样的扭曲圆角。我该怎么办 ？



编辑:这是重现问题的代码:

UISlider *slider = [[UISlider alloc] initWithFrame:CGRectMake(40, 40, 180, 50)];

[slider setMinimumTrackTintColor:[UIColor whiteColor]];

Answer 1

我在增加 slider 高度时遇到了同样的错误。

当 slider 的高度增加时， slider 的边缘失去了圆角。为了修复它，我创建了带有圆角的图像并将其分配给 slider 最小轨道图像。

swift

 override func viewDidLoad() {
        super.viewDidLoad()

        slider.maximumTrackTintColor = UIColor.gray;

        let img:UIImage = GetImage(rectToDraw: CGRect(x: 0, y: 0, width: 400, height: 400));

        slider.setMinimumTrackImage(img.resizableImage(withCapInsets: UIEdgeInsets(top: 13,left: 15,bottom: 15,right: 14)), for: UIControlState.normal)
        slider.setMinimumTrackImage(img.resizableImage(withCapInsets: UIEdgeInsets(top: 13,left: 15,bottom: 15,right: 14)), for: UIControlState.selected)
    }

    func GetImage(rectToDraw:CGRect) -> UIImage {

        let layer:CALayer =  CALayer()
        layer.frame = rectToDraw;
        layer.cornerRadius = 20;
        layer.backgroundColor = UIColor.red.cgColor;
        UIGraphicsBeginImageContext(layer.frame.size)
        layer.render(in: UIGraphicsGetCurrentContext()!)
        let  image :UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()
        return image;
    }

Xamarin.iOS

在自定义渲染器中

 protected override void OnElementChanged(ElementChangedEventArgs<Slider> e)
            {
                MySlideriOS sliderIos = new MySlideriOS();
                SetNativeControl(sliderIos);
                base.OnElementChanged(e);
            }

在自定义 slider 内

 public class MySlideriOS : UISlider
    {
        public UILabel label = null;

        public MySlideriOS()
        {

             this.MaximumTrackTintColor = UIColor.Gray;

            UIImage img = GetImage(new CGRect(0,0,400,400));

            this.SetMinTrackImage(img.CreateResizableImage(new UIEdgeInsets(13, 15, 15,14)), UIControlState.Normal);
            this.SetMinTrackImage(img.CreateResizableImage(new UIEdgeInsets(13, 15, 15, 14)), UIControlState.Selected);


            this.MaxValue = 15;
        }
 public UIImage GetImage(CGRect recttoDraw)
        {
            CGRect rect = recttoDraw;

            CALayer layer = new CALayer();
            layer.Frame = recttoDraw;
            layer.CornerRadius = 20;
            layer.BackgroundColor = UIColor.Red.CGColor;
            UIGraphics.BeginImageContext(layer.Frame.Size);
            layer.RenderInContext(UIGraphics.GetCurrentContext());
            UIImage image = UIGraphics.GetImageFromCurrentImageContext();
            UIGraphics.EndImageContext();
            return image;

        }