Run time viewcontroller

I am creating an app with a tab bar. However, when the app starts, I don't want it to display the t开发者_开发百科ab bar. Instead I would like to show a login page. After a successful log in, the tab bar based application should be shown.

Is this possible in code? I did it with Interface Builder.

Just create a Window-based Application and create a ViewController with a TabBar that you can show once login is successful.

Modal view controllers is the way you can do what you want. As it is said in the documentation

Modal view controllers are a tool that you have at your disposal for interrupting the current workflow and displaying a new set of views.