xamarin.ios - Xamarin.iOS 中的单选按钮听点击？

Question

我需要一个有两个单选按钮的 View ，一次只能点击一个。使用用户 Alanc Liu 在此处发布的答案:Radio button in xamarin.ios我的 View Controller 看起来是正确的，但我不知道如何监听点击以将另一个单选按钮设置为 false。

我试过向 ViewDidLoad 方法添加手势识别器，但还没有任何效果(我以前主要只是使用 Storyboard 来为按钮点击添加方法)。

我的 View Controller :

public partial class VerifyViewController : UIViewController
{
    public VerifyViewController (IntPtr handle) : base (handle)
    {            
    }

    public override void ViewDidLoad()
    {
        base.ViewDidLoad();

        MyRadioButton tBtn = new MyRadioButton(new CGPoint(100, 300), "TEXT PHONE");
        MyRadioButton eBtn = new MyRadioButton(new CGPoint(100, 375), "EMAIL");

        this.Add(tBtn);
        this.Add(eBtn);
    }
}

和他的单选按钮类:

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 ();
    }
}
}

Answer 1

1. 在 MyRadioButton 中公开一个公共(public)事件，当我们点击单选按钮时调用它。

   MyRadioButton 中的代码:

   //define the event inside MyRadioButton
   public delegate void TapHandler(MyRadioButton sender);
   public event TapHandler Tap;
   
   //call it in MyRadioButton(CGPoint pt, string title)
   UITapGestureRecognizer tapGR = new UITapGestureRecognizer(() => {
       State = !State;
       Tap(this);
   });
   

2. 在您的 viewController 中处理事件

   ViewController中的代码

   MyRadioButton tBtn = new MyRadioButton(new CGPoint(100, 300), "TEXT PHONE");
   MyRadioButton eBtn = new MyRadioButton(new CGPoint(100, 375), "EMAIL");
   
   this.Add(tBtn);
   this.Add(eBtn);
   
   tBtn.Tap += Btn_Tap;
   eBtn.Tap += Btn_Tap;
   // set the default selection
   Btn_Tap(tBtn);
   
   MyRadioButton PreviousButton;
   private void Btn_Tap(MyRadioButton sender)
   {
       if(PreviousButton != null)
       {
           //set previous to false
           PreviousButton.State = false;
       }
       //set current to true
       sender.State = true;
       //assign current to previous
       PreviousButton = sender;
   }
   

结果: