UISlider 增加了滑块大小，但在 iOS 应用程序中没有拇指变形 [英] UISlider with increased slider size but no thumb distortion in iOS App

问题描述

我需要在使用 Xamarin Forms 创建的 iOS 应用 中增加滑块的大小.我尝试使用以下自定义渲染器覆盖 LayoutSubviews.它增加了尺寸，但拇指的尺寸增加了不可接受的.如何在保持滑块高度增加的情况下减小拇指的大小?

Android 中是可能的，如下所示:

更新 - 参考 - 渲染器

1. 这是示例

   I need to increase size of slider in the iOS app created using Xamarin Forms. I tried with following custom renderer that overrides LayoutSubviews. It increases the size but there is an unacceptable size increase for the thumb. How to reduce the size of the thumb keeping the increased height of the slider?

   It is possible in Android as shown here: Increase height of slider without affecting thumb in Android App

   iOS References:

   1. Custom UISlider - Increase "hot spot" size

   2. Increasing a thumbs "click area" in UISlider

   C# Custom Renderer

   [assembly: ExportRenderer(typeof(MySlider), typeof(MySliderRenderer))]
   namespace CustomRenderer.iOS
   {
       class MySliderRenderer : Xamarin.Forms.Platform.iOS.SliderRenderer
       {
           protected override void OnElementChanged(ElementChangedEventArgs<Slider> e)
           {
               base.OnElementChanged(e);   
               Control.MinimumTrackTintColor = UIColor.FromRGB(0xE6, 0x00, 0x06);
               Control.ThumbTintColor = UIColor.Red;
               Control.MinimumTrackTintColor = UIColor.Orange;
               Control.MaximumTrackTintColor = UIColor.Yellow;
               //Control.SetThumbImage(UIImage.FromFile("myicon.png"), UIControlState.Normal);
           }
   
           public override void LayoutSubviews()
           {
               base.LayoutSubviews();
               CGAffineTransform transform = CGAffineTransform.MakeScale(1f, 12.0f);
               transform.TransformSize(this.Frame.Size);
               this.Control.Transform = transform;            
           }
       }
   }
   

   UPDATE - REFERENCES - Renderer

   1. Customizing Control Rendering in Xamarin.Forms

   2. Implementing a View - Rendering a platform-specific view

   3. iOS range slider for Xamarin and Xamarin.Forms

   4. Fullscreen Video Background Control for Xamarin.Forms

   解决方案

   Override TrackRectForBounds to change its height instead of changing transform .

   In MySliderRenderer

   class MySliderRenderer : SliderRenderer
   {
       protected override void OnElementChanged(ElementChangedEventArgs<Slider> e)
       {
           SetNativeControl(new MySlideriOS());
           base.OnElementChanged(e);
       }
   }
   

   Create a subclass of UISlider

   public class MySlideriOS : UISlider
   {
       public MySlideriOS() {
           this.MinimumTrackTintColor = UIColor.FromRGB(0xE6, 0x00, 0x06);
           this.ThumbTintColor = UIColor.Red;
           this.MinimumTrackTintColor = UIColor.Orange;
           this.MaximumTrackTintColor = UIColor.Yellow;
       }
   
       public override CGRect TrackRectForBounds(CGRect forBounds)
       {
           CGRect rect =  base.TrackRectForBounds(forBounds);
           return new CGRect(rect.X, rect.Y, rect.Width, 20);
       }
   }
   

   My test

   Here is Sample

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