BottomBar Renderer

BottomBarRender.cs

using System;
using System.Collections.Generic;

using MonoTouch.UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

using CustomFormsSample.Views;
using CustomFormsSample.iOS.Views;

[assembly: ExportRenderer(typeof(BottomBar), typeof(BottomBarRenderer))]

namespace CustomFormsSample.iOS.Views
{
    public class BottomBarRenderer : ViewRenderer<BottomBar, UIToolbar>
    {
        private UIBarButtonItem button1;
        private UIBarButtonItem button2;

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

            if (e.OldElement == null)
            {
                var toolBar = new UIToolbar()
                {
                    BarStyle = UIBarStyle.Default,
                };

                this.button1 = new UIBarButtonItem("1", UIBarButtonItemStyle.Bordered, this.OnFirst)
                {
                    AccessibilityLabel = "1",
                };

                this.button2 = new UIBarButtonItem("2", UIBarButtonItemStyle.Bordered, this.OnSecond)
                {
                    AccessibilityLabel = "2",
                };

                var barItems = new List<UIBarButtonItem>()
                {
                new UIBarButtonItem(UIBarButtonSystemItem.FlexibleSpace),
                this.button1,
                new UIBarButtonItem(UIBarButtonSystemItem.FlexibleSpace),
                this.button2,
                new UIBarButtonItem(UIBarButtonSystemItem.FlexibleSpace),
                };

                toolBar.SetItems(barItems.ToArray(), true);

                this.SetNativeControl(toolBar);
                this.SetNeedsDisplay();
            }
        }

        private void OnFirst(Object sender, EventArgs e)
        {
            new UIAlertView("Tapped", "1 Tapped", null, "OK", null).Show();
        }

        private void OnSecond(Object sender, EventArgs e)
        {
            new UIAlertView("Tapped", "2 Tapped", null, "OK", null).Show();
        }
    }
}