Confused About Window Based Application in Xcode 4

开发者_StackOverflow社区What is the purpose of Window Based Application project in Xcode 4? When I create a Window Based Application project it creates iPhone folder and iPad folder. I write most of my code in the MyProjectNameAppDelegate.m files. What is the purpose of the files inside the iPhone folder and iPad folder?

The Window Based Apllication project is often used to develop Universal Apps, i.e. apps that runs on iPad and iPhone devices. For Universal Apps you'll need seperate user intefaces for each device, the respective default folders to store the the XIBs for these interfaces are the iPhone and iPad folder.