You can do something like this,
for(UIView *view in self.tabBarController.view.subviews)
{
if([view isKindOfClass:[UITabBar class]])
{
[view setFrame:CGRectMake(view.frame.origin.x, 1024, view.frame.size.width, view.frame.size.height)];
}
else
{
[view setFrame:CGRectMake(view.frame.origin.x, view.frame.origin.y, view.frame.size.width, 1024)];
}
}
Note: this is tested in ios 6 and earlier versions, so if you want to run in ios 7 and more set frame and some flag for frame.