A MonoTouch iOS Mail like example with a custom view and a UIWebView

MailViewTestViewController.cs

using System;
using System.Drawing;
using System.IO;
using System.Net;
using MonoTouch.Foundation;
using MonoTouch.UIKit;

// A MonoTouch iOS Mail like example with a custom view and a UIWebView :
//
// http://stackoverflow.com/questions/10434444/zoom-a-uiwebview-like-ios-mail-app/10463431
//
// andywhitt[at]gmail.com

namespace MailViewTest
{	
	public partial class MailViewTestViewController : UIViewController
	{
		UILabel customView; // customview, in this example its just a UILabel
		
		UIView fakeBackgroundView = new UIView();
						
		private bool _loaded;
		
		public MailViewTestViewController () : base ("MailViewTestViewController", null)
		{
		}
				
		public override void ViewDidLoad ()
		{
			base.ViewDidLoad ();
			customView = new UILabel (new RectangleF (0, 0, View.Frame.Width, 50)) { Text = "Testing Text" };
			webView.BackgroundColor = UIColor.ScrollViewTexturedBackgroundColor;
			webView.LoadFinished += HandleWebViewLoadFinished;
			webView.ScalesPageToFit = true;
			
			// grab some html
			var request = WebRequest.Create ("http://www.stackoverflow.com");
			var response = request.GetResponse (); 
			var reader = new StreamReader (response.GetResponseStream ());
			
			// HACK : add ViewPort meta tag so that if the page is smaller than the View it will zoom correctly
			var str = "<meta name=\"viewport\" content=\"width=320\"/>" + reader.ReadToEnd ();
			webView.LoadHtmlString (str, null);			
			webView.ScrollView.WeakDelegate = this;
			webView.ScrollView.AddSubview (customView);
			
			// remove the webviews shadow and update all others subviews Y
			foreach (var subview in webView.ScrollView.Subviews) {
				if (subview == customView)
					continue;
				else if (subview is UIImageView) // remove shadow
					subview.Hidden = true;
				else
					subview.Frame = new RectangleF (new PointF (subview.Frame.X, subview.Frame.Y + customView.Frame.Height), subview.Frame.Size);
			}
		}
		
		[Export("scrollViewDidScroll:")]
		private void HandleWebViewScrollViewScrolled (UIScrollView scrollView)
		{	
			float x = 0;
		    if(scrollView.ContentOffset.X < 0)
		    	x = 0;
			else if((scrollView.ContentOffset.X + customView.Frame.Size.Width) > scrollView.ContentSize.Width)
		        x = scrollView.ContentSize.Width - customView.Frame.Size.Width;
		    else
		        x = scrollView.ContentOffset.X;
			customView.Frame = new RectangleF(new PointF(x, customView.Frame.Y), customView.Frame.Size);
		}
				
		private void HandleWebViewLoadFinished (object sender, EventArgs e)
		{
			if (_loaded)
				return;
			
			// add the fake white background so it looks like Mail
			fakeBackgroundView.BackgroundColor = UIColor.White;
			fakeBackgroundView.Frame = new RectangleF (new PointF (0, 0), webView.ScrollView.ContentSize);
			webView.ScrollView.AddSubview (fakeBackgroundView);
			webView.ScrollView.SendSubviewToBack (fakeBackgroundView);
			
			_loaded = true;
		}
		
		public override void DidRotate (UIInterfaceOrientation fromInterfaceOrientation)
		{
			// update the fakebackground frame
			fakeBackgroundView.Frame = new RectangleF (new PointF (0, 0), webView.ScrollView.ContentSize);
		}
		
		public override bool ShouldAutorotateToInterfaceOrientation (UIInterfaceOrientation toInterfaceOrientation)
		{
			// Return true for supported orientations
			return (toInterfaceOrientation != UIInterfaceOrientation.PortraitUpsideDown);
		}
	}
}