Що таке qwidget у qt?

What is QWidget in Qt?

The QWidget class provides the basic capability to render to the screen, and to handle user input events. All UI elements that Qt provides are either subclasses of QWidget, or are used in connection with a QWidget subclass.

How do you get the size of the QWidget?

QWidget::size() gives you the current size of a widget. If the widget is not yet shown then no layout has adjusted its size and you will usually get the "design time size" as you put it. If you need the size of the widget as shown then you need to call size() after the widget is visible.

What are the QWidget mouse events?

Mouse events occur when a mouse button is pressed or released inside a widget or when the mouse cursor is moved. Mouse move events will occur only when a mouse button is pressed down, unless mouse tracking has been enabled with QWidget::setMouseTracking().

What is the use of QFrame?

The QFrame class can also be used directly for creating simple placeholder frames without any contents. The frame style is specified by a frame shape and a shadow style that is used to visually separate the frame from surrounding widgets.

Класс QWidget является базовым для всех объектов пользовательского интерфейса. Далее… Унаследован от: QObject and QPaintDevice.
Since QWidget is a subclass of QPaintDevice, subclasses can be used to display custom content that is composed using a series of painting operations with an …
Усі віджети у Qt успадковують від класу QWidget. Клас QWidget надає базову функціональність спільну для всіх віджетів.