How to make my ImageView zoomable?

Can anyone help on how to use the matrix scaletype to zoom an imageview and also how to use the translate method so that it can be focused at the center? I have tried using webview to be able to use the zooming and scrolling functionalities i needed but it is not nice to look at.

I found a tutorial divided into 4 parts from a blog on how to zoom and pan an image and it is quite nice. It has sample codes that can be downloaded and some explanations. It also have other tutorials.

Update - pointed the links to the new ones.

Update 2 - I found a ready-to-use class for ImageView zooming functionality. You check it out here.