iOSFocusEvents.cs

using System;
using SampleApp.DependencyServices;
using Xamarin.Forms;
using SampleApp.iOS;
using Xamarin.Forms.Platform.iOS;

[assembly: ExportRenderer(typeof(IFocusEvents), typeof(iOSFocusEvents))]
namespace SampleApp.iOS
{
    public class iOSFocusEvents : ImageRenderer
    {

        protected override void OnElementChanged(ElementChangedEventArgs<Image> e)
        {
            base.OnElementChanged(e);

            if (Control != null)
            {
                SetNativeControl(new CustomButton());
            }
        }

        
        


    }

    public class CustomButton : FormsUIImageView
    {
        

        public CustomButton() : base()
        { 
            Console.WriteLine("Custom button created");
        }



        public override void AccessibilityElementDidBecomeFocused()
        {
            base.AccessibilityElementDidBecomeFocused();
            
            Console.WriteLine("Ding Dong");
            
        }

        public override void AccessibilityElementDidLoseFocus()
        {
            base.AccessibilityElementDidLoseFocus();
            Console.WriteLine("Campanello ha perso il focus");

        }




    }
}