How to change a widget to other widget in layout?

[Kevin Hoang]

I have a form (widget form) on this form has 3 widgets: header, centralWidget, footer. A vertical layout to wrap them, like this:

__________________________________________________ ______________
|
| Header Widget contains Navigation To other forms
|_________________________________________________ ______________
|
|
|
| Central Widget
|
|
|
|_________________________________________________ ______________
|
| Footer Widget
|_________________________________________________ ______________

The footer and header widget are no changes, but Central Widget always change when users click any items of the navigation.

My question is: How to change the Central Widget to other widget when click on a button? Which classes helps me do this?