Keeping the Concepts from Being a GUI Mess

In this chapter, you learned the following:

• Most modern programs provide a graphical user interface (GUI) for displaying information and interacting with users. GUIs are built out of widgets, such as buttons, sliders, and text panels; all modern programming languages provide at least one GUI toolkit.

• Unlike command-line programs, GUI applications are usually event-driven. In other words, they react to events such as keystrokes and mouse clicks when and as they occur.

• Experience shows that GUIs should be built using the model-view-controller pattern. The model is the data being manipulated; the view displays the current state of the data and gathers input from the user, while the controller decides what to do next.

• Lambda expressions create functions that have no names. These are often used to define the actions that widgets should take when users provide input, without requiring global variables.

• Designing usable GUIs is as challenging a craft as designing software. Being good at the latter doesn’t guarantee that you can do the former, but dozens of good books can help you get started.