Serialization is a good way to make your data persistent when you close your application. In this chapter, you learned to make your C++ objects serializable with QVariant. You created a flexible serialization structure with the Bridge pattern. You saved an object in a different text format such as JSON or XML and also in a binary format.
You also learned to use the Qt Multimedia module to play some sound effects. These sounds can be triggered by a mouse click or by a keyboard key. You implemented a friendly user interaction, allowing you to load a new sound with a file drag and drop.
In the next chapter, we will discover the QTest framework and how you can organize your project so it has a clean application/test separation.