How to change a TabActivity's view from a child activity

I have a TabActivity with 4 tabs. When a user clicks on the 4th tab, a ListView Activity is displayed. Then when a user clicks on one of the items in the list, yet another Activity is launched that plays videos, and all the tabs are visible. I would like to hide the tabs and everything else so the video can be as big as possible, but I am having a hard time figuring out how to manipulate the TabActivity's view from within the secondary Activity. Calling:

this.requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
             WindowManager.LayoutParams.FL开发者_如何学GoAG_FULLSCREEN);

is not doing it. Anyone know?

If you hide all tab for video playing,how do you return to tab interface?press back key?if you want to do that ,why don't just launch an activity? You can never hide tab views by using setFlags.