position of UITabbar

I try to place UITabbar on iPhone window us开发者_开发百科ing CGRectMake. But I found that the Y position is different from the display in Interface Builder.

Is there anyone met the same problem?

Using CGRectMake to locate the x,y position, is it possible cause the refusing from App stoe due to compatible reason?

Thanks

interdev

If your tab bar is associated with a tab bar controller it may not be moved in code. From Apple's documentation:

"Important: In iPhone OS 3.0 and later, you should not attempt to use the methods and properties of this class to modify the tab bar when it is associated with a tab bar controller object. Modifying the tab bar in this way results in the throwing of an exception. Instead, any modifications to the tab bar or its items should occur through the tab bar controller interface. You may still directly modify a tab bar object that is not associated with a tab bar controller."

http://developer.apple.com/iphone/library/documentation/uikit/reference/UITabBar_Class/Reference/Reference.html