The document provides examples of using Qt widgets and classes in Ring. It demonstrates how to:
1. Create a main window with a menu bar containing File and Exit options.
2. Add a status bar to the window and set properties like window title, stylesheets, and mouse tracking.
3. Use QLineEdit to get user input, and QMessageBox to display messages.
4. Respond to QLineEdit events like text changed and return pressed.
5. Use other widgets like QProgressBar and respond to their signals and events.
6. Draw on widgets using QPainter, and print to PDF using QPrinter.
7. Play audio files with QMediaPlayer and get colors from the user with