What is QObject class?

What is QObject class?

Detailed Description. QObject is the heart of the Qt Object Model. The central feature in this model is a very powerful mechanism for seamless object communication called signals and slots. You can connect a signal to a slot with connect() and destroy the connection with disconnect().

Where is Q_OBJECT defined?

The Q_OBJECT macro must appear in the private section of a class definition that declares its own signals and slots or that uses other services provided by Qt’s meta-object system.

What is Q_gadget?

Q_GADGET main usage is to allow a non QObject type to have introspection. The Q_GADGET macro is a lighter version of the Q_OBJECT macro for classes that do not inherit from QObject but still want to use some of the reflection capabilities offered by QMetaObject.

What is QObject?

QObject is the heart of the Qt Object Model. The central feature in this model is a very powerful mechanism for seamless object communication called signals and slots. You can connect a signal to a slot with connect() and destroy the connection with disconnect().

What is QQmlApplicationEngine?

QQmlApplicationEngine provides a convenient way to load an application from a single QML file.

Why is QObject used?

Besides signals and slots, the Q_OBJECT macro provides the meta object information that is associated with given class. As stated in the documentation: we strongly recommend that all subclasses of QObject use the Q_OBJECT macro regardless of whether or not they actually use signals, slots, and properties.

How does QML define enum?

You can define one with the enum keyword. The type and its values must start with a capital letter but otherwise follow rules for naming a variable (e.g. can include digits and underscore). To use the enum, you have to explicitly include the full scope including the component ComponentName. EnumType.

What is private slot?

Declaring slots as private means that you won’t be able to reference them from context in which they are private, like any other method. Consequently you won’t be able to pass private slots address to connect .

What is QQuickWidget?

The QQuickWidget class provides a widget for displaying a Qt Quick user interface. This class was introduced in Qt 5.3.

When should I use Q_OBJECT?

4 Answers. You should use the Q_OBJECT macro for any non-templated classes that derive from QObject . Besides signals and slots, the Q_OBJECT macro provides the meta object information that is associated with given class.