Serialization is a good way to make your data persistent when you close your application. In this chapter, you learned how to make your C++ objects serializable with QVariant. You created a flexible serialization structure with the bridge pattern. You saved an object in different text formats, namely the JSON, XML, and binary formats.
You also learned how to use the Qt Multimedia module to play some sound effects. These sounds can be triggered by a mouse click or by pressing a keyboard key. You implemented a friendly user interaction, allowing you to load a new sound by dragging and dropping a file.
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.