Detect Single Tap on UIWebView

View.cs

namespace App.iOS
{
	public partial class PaperView : UIViewController
	{
		// webView is a UIWebView
		// toolbar is a UIToolbar
		
		public override void ViewDidLoad ()
		{
			base.ViewDidLoad ();
 
			var tapRecognizer = new UITapGestureRecognizer (this, new Selector ("HandleTapFrom"));
			tapRecognizer.NumberOfTapsRequired = 1;
			tapRecognizer.Delegate = new GestureDelegate ();

			webView.AddGestureRecognizer (tapRecognizer);
		}

		[Export("HandleTapFrom")]
		public void HandleTapFrom (UITapGestureRecognizer recognizer)
		{
			// call this js in the webview to see if we selected anything
			var selection = webView.EvaluateJavascript ("window.getSelection().toString()");
			if (selection.Length <= 0) {			
				if (toolbar.Alpha.Equals (1f)) {
					toolbar.Alpha = 0f;
				} else {
					toolbar.Alpha = 1f;
				}
			} else {
				Console.WriteLine ("user is selecting text");
			}
		}
	}
	
	// delegate methods for UITapGestureRecognizer
	public class GestureDelegate : UIGestureRecognizerDelegate
		{
			public override bool ShouldReceiveTouch (UIGestureRecognizer recognizer, UITouch touch)
			{
				return true;
			}

			public override bool ShouldBegin (UIGestureRecognizer recognizer)
			{
				return true;
			}

			public override bool ShouldRecognizeSimultaneously (UIGestureRecognizer gestureRecognizer, UIGestureRecognizer otherGestureRecognizer)
			{
				return true;
			}
		}
}