How to implement Android Pull-to-Refresh

In Android applications such as Twitter (official app), when you encounter a ListView, you can pull it down (and it will bounce back when released) to refresh the content.

Refresh image with a new one at the same url

I am accessing a link on my site that will provide a new image each time it is accessed.

Fields are cleared but just when I press F5

I don't know if it is a common problem, but this strange problem is giving me some headache... I'm having an strange behavior, my application has a lot of dialogs, and when user opens one, the dialog should show default content. The problem is that I clear all bean's properties before show the dialog, but sometimes it appears that the form isn't cleared!! For example, this is one of the dialogs that are having this problem: