The QCloseEvent class contains parameters that describe a close event.| doc.qt.io
The QDialog class is the base class of dialog windows.| doc.qt.io
The QPushButton widget provides a command button.| doc.qt.io
The QAbstractButton class is the abstract base class of button widgets, providing functionality common to buttons.| doc.qt.io
The QWidget class is the base class of all user interface objects.| doc.qt.io
The QEvent class is the base class of all event classes. Event objects contain event parameters.| doc.qt.io
The Qt namespace contains miscellaneous identifiers used throughout the Qt library.| doc.qt.io
The QLayout class is the base class of geometry managers.| doc.qt.io