Let's start implementing the base structure on top of which we'll implement the entire app.
Let's start creating a new app called Todolist using the Single View Application template in Xcode. The app will be in portrait mode only, so you must uncheck Landscape from the allowed device orientations:
Although Apple has improved Interface Builder in Xcode 7, most developers still favor writing the layout in code instead of using Interface Builder. The common reasons are that with Interface Builder, it is more difficult to create reusable views, which makes working in a team difficult because of merging of the storyboard files; in general, it is more difficult to debug a complex layout.
However, Apple strongly encourages that you use Interface Builder to build User Interface and we will use it to build our first complex app. To show the difference, the app in the next chapter will be built using Auto Layout by code, helped by a third-party library...