The use UITabBarController

UITabBarController appDelegate which when added in the non-existence of the position will be offset downward
I am now a landing page does not require UITabBarController, after the successful landing pages only need UITabBarController,
Online to find some inside information that must be added in appDelegate offset downward position will not appear in the non-appDelegate inside pages do not use it?

Such as: landing page loginViewController, jump pages functionViewController, how do I do to add to
UITabBarControllerfunctionViewController leaving UITabBarController do not shift down, you reach people seeking a reasonable solution ~
Reply:
Seems to be using self.rootViewController = loginViewContoller;
Instead of [self.window addSubView: loginViewController];
Reply:
I just make a [self.window addSubView: loginViewController]; complete landing page Skip functionViewController added UITabBarController, there will be offset downward UITabBarController ~ ~ ~
Reply:
In fact, the problem is that the screen to jump. . .

You try a few pages to jump, or addsubview, insertview way to try on it

XIB file in either fixed coordinates can also be a