Creating a successful application is not only a matter of writing efficient and reliable code. User interfaces and experience are relevant topics that we have to seriously take into account during the development process. If you want to be able to create appealing and well-structured layouts, you need to become familiar with the main building blocks of user interfaces.

In this chapter, we will explore the basics of iOS UI development, which you will use and improve upon for the rest of the book and, hopefully, for the rest of your career.

We will start from the fundamental actors of a user interface, such as windows and views; then, we will connect the dots showing how all these components work together by creating a UI hierarchy and how the system interacts with all these elements.

Let's start our journey from the element at the top of the stack: the window.