How to share data between activity and widget?

I read the hellowidget tutorial and Dev Guide' App Widgets. Then I know how to create a widget which contains button or text or something.

But what I really want to do is making it interact with my app. For example, I want to create a widget that has a text view, and when I click it, it sends a PendingIntent to my activity in which I can edit the text.

I can do the step "sends a PendingIntent". But after I edit text in acitivy, how does the widget read it?