Extend your view controller from UIViewController, build it in your familiar way.
Push/Pop view controller in to/out of popup view stack, and set navigation items by using self.navigationItem.leftBarButtonItem and rightBarButtonItem, just like you are using UINavigationController.
Support both "Form Sheet" and "Bottom Sheet" style.
Work well with storyboard(including segue).
Customize UI by using UIAppearance.
Auto-reposition of popup view when keyboard is showing up, make sure your UITextField/UITextView won‘t be covered by the keyboard.
Drag navigation bar to dismiss popup view.
Support both portrait and landscape orientation, and both iPhone and iPad.
