Android app layout help

I'm building a screen with this design:

• a tabActivity (call it "MAIN tabhost")
• its tabwidget is at the bottom of the screen
• the content of this tabhost MAIN refers to a new TabActivity which has its tabwidget at th开发者_如何学运维e top of the screen and its content is a ListActivity.

I'm new with android development, and I really dont understand if its the correct approach to use one activity with other activities inside. This is currently working, but I have a couple of bugs and really don't understand how to fix them or how to start without taking a whole new approach...

Source code (zip)

The bugs:

1.- If the listactivity has enough items it shows over the MAIN tabwidget when scrolling

2.- When you stop scrolling the listview it appears behind the MAIN tabwidget

3.- When you press a tab button on the secondary tabhost, it shows for a very short lapse the icon that is being used in the bottom tabhost (MAIN)

I know that if you add an bottom margin to the listView that is the height of your buttons on the bottom you will get rid of the listView going behind and in front of the buttons. I am not sure if that will fix both issues. I would try that first though.