Blackberry custom UI and custom Components

I have been working quite sometime with Blackberry application development but customizing UI and components is something am not very familiar with. I understand that the sublayout, paint, getpreferredWidth, getpreferredHeight methods are to be overridden to customize layouts and com开发者_如何学Goponents. But still the idea is very vague to me. I am still not able to confidently proceed with the development of UI using these concepts. Can someone explain to me the basics of this? I would like to have a clear understanding from the experts out there.

Best thing to do is look at the source code to the Advanced UI Components that RIM provides, in conjunction with the API documentation.