xamarin.ios 半圆角按钮Readerer

xamarin.from上可以使用本身的button实现圆角带图标的按钮，但是没有半圆角的按钮实现，需要自己使用Renderer重新写过来重写一个button。

下面是一个重写的带边框的方式，代码如下：

 using UIKit;
 using Xamarin.Forms.Platform.iOS;
 using Xamarin.Forms;
 using CoreAnimation;
 using System.ComponentModel;

 [assembly: ExportRenderer(typeof(Test.Renderers.MyRadiusButton), typeof(Test.iOS.Renderers.MyRadiusButton))]
 namespace Test.iOS.Renderers
 {
     public class MyRadiusButton : ButtonRenderer
     {
         bool btnStatus = true;
         bool radiusLeft = true;
         protected override void OnElementChanged(ElementChangedEventArgs<Button> e)
         {
             base.OnElementChanged(e);
             Test.Renderers.MyRadiusButton view = Element as Test.Renderers.MyRadiusButton;
             radiusLeft = view.RadiusLeft;
             if (e.OldElement == null)
             {
                 UIBezierPath maskPath;

                 double widthLength =  /  - ;
                 maskPath = UIBezierPath.FromRoundedRect(new CoreGraphics.CGRect(, , widthLength, ), UIRectCorner.TopLeft | UIRectCorner.BottomLeft, new CoreGraphics.CGSize(, ));

                 CAShapeLayer maskLayer = new CAShapeLayer();
                 //maskLayer.Frame = new CoreGraphics.CGRect(0, 0, widthLength, 35);
                 maskLayer.Path = maskPath.CGPath;
                 maskLayer.StrokeColor = new CoreGraphics.CGColor(, , );//边框颜色

                 CAShapeLayer borderLayer = new CAShapeLayer();
                 borderLayer.Path = maskPath.CGPath;
                 borderLayer.Frame = new CoreGraphics.CGRect(, , widthLength, );
                 borderLayer.FillColor = new CoreGraphics.CGColor(, , , 0f);
                 borderLayer.StrokeColor = new CoreGraphics.CGColor(0.23f, 0.72f, 0.47f, 1.0f);
                 borderLayer.LineWidth = ;

                 Control.Layer.Mask = maskLayer;
                 Control.Layer.AddSublayer(borderLayer);
                 Control.Layer.MasksToBounds = true;
                 Control.SetTitleColor(UIColor.FromRGB(, , ), UIControlState.Normal);
                 Control.BackgroundColor = UIColor.FromRGB(, , );

                 view.Clicked += (sender, even) =>
                 {
                     if (!view.BtnSelected)
                     {
                         if (btnStatus)
                         {
                             Control.SetTitleColor(UIColor.FromRGB(, , ), UIControlState.Normal);
                             Control.BackgroundColor = UIColor.FromRGB(, , );
                             btnStatus = !btnStatus;
                         }
                         else
                         {
                             Control.SetTitleColor(UIColor.FromRGB(, , ), UIControlState.Normal);
                             Control.BackgroundColor = UIColor.FromRGB(, , );
                             btnStatus = !btnStatus;
                         }
                         view.BtnClickAction?.Invoke();
                     }
                 };

             }
         }
     }
 }