I want to make a UISplitViewController in portrait mode just like in the Settings app. How can I do it?
From the UISplitViewController class documentation:
A split view controller supports the same interface orientations as its currently visible child view controllers. Both view controllers are displayed in landscape orientations but only the detail view controller is displayed in portrait orientations. When transitioning between orientations, the split view controller sends messages to its delegate object to coordinate the display of a popover with the hidden view controller. For more information on the methods of this delegate object, see UISplitViewControllerDelegate Protocol Reference.
(Emphesis added.)
A bit late, but also take a look at the MGSplitViewController by Matt Gemmel. It does what you need and so much more. It's what UISplitViewController should be, and it's a snap to implement.