创建单选按钮组Xamarin.iOS

Question

我正在创建单选按钮组。 Xamarin.iOS中的内置版本不可用。但是我创建了2个单选按钮，但是两个都是独立的（不像单选按钮组那样） 我一次只需要选择一个选项，并且需要与文本相关的选定单选按钮。 我的代码

public override void ViewDidLoad()
{
    base.ViewDidLoad();
    var rBtn = new MyRadioButton(new CGPoint(20, 70), "Generic");
    this.Add(rBtn);
    var rBtn2 = new MyRadioButton(new CGPoint(160, 70), "Subject");
    this.Add(rBtn2);
}

MyRadioButton使用了avobe。

 public class MyRadioButton : UIView
    {
    private CircleView circleView;
    private UILabel lbTitle;

    public bool State {
        get {
            return circleView.State;
        }
        set {
            circleView.State = value;
        }
    }

    public MyRadioButton (CGPoint pt,string title)
    {
        this.Frame = new CGRect (pt, new CGSize (150, 30));
        circleView = new CircleView (new CGRect(0, 0, 30, 30));
        lbTitle = new UILabel (new CGRect (30, 0, 120, 30));
        lbTitle.Text = title;
        lbTitle.TextAlignment = UITextAlignment.Center;
        this.AddSubview (circleView);
        this.AddSubview (lbTitle);
        this.BackgroundColor = UIColor.FromRGBA(1,0,0,0.3f);
        UITapGestureRecognizer tapGR = new UITapGestureRecognizer (() => {
            State = !State;
        });
        this.AddGestureRecognizer (tapGR);
    }
    }

    class CircleView : UIView
    {
    private bool state = false;
    public bool State { 
        get {
            return state;
        }
        set {
            state = value;
            this.SetNeedsDisplay ();
        }
    }

    public CircleView (CGRect frame)
    {
        this.BackgroundColor = UIColor.Clear;
        this.Frame = frame;
    }

    public override void Draw (CoreGraphics.CGRect rect)
    {
        CGContext con = UIGraphics.GetCurrentContext ();

        float padding = 5;
        con.AddEllipseInRect (new CGRect (padding, padding, rect.Width - 2 * padding, rect.Height - 2 * padding));
        con.StrokePath ();

        if (state) {
            float insidePadding = 8;
            con.AddEllipseInRect (new CGRect (insidePadding, insidePadding, rect.Width - 2 * insidePadding, rect.Height - 2 * insidePadding));
            con.FillPath ();
        }
    }
    }

请参见下面的输出屏幕截图，我可以选择两个单选按钮。他们的行为不像小组