UrlImageStoreExample.cs

using System;
using MonoTouch.UIKit;
using MonoTouch.UrlImageStore;

namespace FbGroups
{
	public class UrlImageStoreExample : IUrlImageUpdated<string>
	{
		//Event to raise when our image is lazily loaded
		public delegate void ImageLoadedDelegate(string id, UIImage image);
		public event ImageLoadedDelegate ImageLoaded;
		
		//Our UrlImageStore
		UrlImageStore<string> imageStore;
		
		public UrlImageStoreExample()
		{
			//This would be what you want to display while the image is lazily loaded
			UIImage defaultImage = UIImage.FromFileUncached("DefaultUrlStoreImage.png");
		
			//Create our image store with a capacity of 50 in its cache
			// the image store's name is used to create a folder to save cached images to
			// so keep this in mind and avoid collisions
			//The processimagedelegate (see line 54) lets us do whatever we need to our images
			// before they get cached
			imageStore = new UrlImageStore<string>(50, "exampleStore", processImage);			
			imageStore.DefaultImage = defaultImage;
		}
	
		public UIImage RequestImage(string id, string url)
		{
			//We'll pass off the request to the actual image store, which will either return the 
			// actual image if it's already cached (either on disk or in memory)
			// or it will queue up the lazy load, and we'll be notified (this) when that is done
			return imageStore.RequestImage(id, url, this);
		}
		
		//This is from the IUrlImageUpdated interface, and lets us be told when an image has been loaded
		// if it was lazily loaded.
		// this never gets called if the initial ImageStore.RequestImage call finds the image in the cache
		// since that would not be necessary
		public void UrlImageUpdated (string id)
		{
			//Silly to in a way, re-raise this 'event', but just showing an example
			// You'd likely want to use this method to set your UIImageView.Image = imageStore.GetImage(id)
			// or something similar
			if (this.ImageLoaded != null)
				this.ImageLoaded(id, imageStore.GetImage(id));
		}
		
		//This handles our ProcessImageDelegate
		// just a simple way for us to be able to do whatever we want to our image
		// before it gets cached, so here's where you want to resize, etc.
		UIImage processImage(UIImage image, string key)
		{
			//First scale it down to a max of 48 width OR 48 height,
			// but keeping proporations
			var result = Graphics.Scale(image, 48);
			
			//Next, round the corners of the scaled image
			result = Graphics.RoundCorners(result);
			return result;
		}
	}
}