Need advice: Should I use a Layout?

I have a simple app that has a navigation panel at the bottom of the screen with buttons on it and a seekbar. The panel takes up maybe 15% of the screen height and occupies the full width of the screen. The rest of the screen contents are generated at runtime when the user clicks on the panel buttons. The panel will have 3 "pages" where each page has a different set of views displayed.

So far I have used the Designer to design the app, which only has the panel in it. The contents of this panel will change (different views will be displayed on the panel) when the user presses the forward or back buttons (this also updates the main activity window using code).

My question is:
1) Do I use the Designer and design 1 layout for the app and hide/unhide the views on this panel using code? This could get messy because the Designer will have a dozen views on it, 60% of them will be hidden at runtime.

2) Do I use the Designer and design a panel for each page of this navigation panel and load the correct layout into the panel?

3) Do I design the panel using code and forget about the Designer altogether? This allows me to control the positions and widths of the views on this panel using code so it fits on any Android device.

Any advice would be appreciated. If someone can point me to documentation or a working example, that would be great too.

Widget