Qt can slots return value

By Publisher

The Qt keywords signals and slots, which can be found in the class header, are only useful to the Qt metacompiler (the moc).

See Concepts - Visual Parent in Qt Quick for more details. QSound Class | Qt Multimedia 5.12.3 Qt provides the most commonly required audio operation in GUI applications: asynchronously playing a sound file. This is most easily accomplished using the static play() function: The QtWebKit Bridge | Qt 4.8 The JavaScript environment can then use the pixmap from Qt and display it inside the HTML environment, by assigning it to an existing element with assignToHTMLImageElement(). QTest Namespace | Qt Test 5.12.3

Signals and slots can take any number of arguments of any type. ... int value() const { return m_value; } public slots: void setValue(int value); signals: void ...

Qt::AutoConnection is the default value for any QObject::connect(...) call. If both QObjects that are about to be connected are in the same thread, a Qt::DirectConnection isYou can visualize it that way: If you call the Signal the method generated by Qt for you calls all Slots in place and then returns. 20 ways to debug Qt signals and slots | Sam Dutton’s…

Connecting QML Signals in PySide - Qt Wiki

Qt itself will not throw exceptions. Instead, error codes are used. In addition, some classes have user visible error messages, for example QIODevice::errorString() or QSqlQuery::lastError(). This has historical and practical reasons … QHeaderView Class | Qt Widgets 5.12.2 This value is used in QTableView::sizeHintForColumn(), QTableView::sizeHintForRow() and QTreeView::sizeHintForColumn(). Reimplementing these functions can make this function not having an effect. Connecting QML Signals in PySide - Qt Wiki It is possible for slots to return values to the QML caller (see example qmltopy2). In this case, the Python slot needs to define an explicit return type: C++11 in Qt5

Qt for Beginners - Qt Wiki

QMetaMethod Class | Qt Core 5.12.2 Because signals and slots can be dynamically invoked, you must enclose the arguments using the Q_ARG() and Q_Return_ARG() macros. Q_ARG() takes a type name and a const reference of that type; Q_Return_ARG() takes a type name and a non-const … Technical FAQ - Qt Wiki You can rotate items in a QGraphicsView http://doc.qt.io/qt-5/qgraphicsview.html using the mouse by reimplementing the mousePressEvent() http://doc.qt.io/qt-5/qgraphicsitem.​html#mousePressEvent and mouseMoveEvent() http://doc.qt.io/qt-5 … Exposing Attributes of C++ Types to QML | Qt QML 5.12.3 Any data that is transferred from C++ to QML, whether as a property value, a method parameter or return value, or a signal parameter value, must be of a type that is supported by the QML engine. QAbstractItemModel Class | Qt Core 5.12.3

The signals and slots mechanism is a central feature of Qt and probably the part that differs most from the features provided by other frameworks.Slots can be used for receiving signals, but they are also normal member functions. Just as an object does not know if anything receives its signals, a slot does...

Debugging Qt's signal-slot connections… – Ray Rischpater, KF6GPE Feb 13, 2012 ... What do you do if you think you've correctly connected a signal to a slot ... If need be, ensure that connect succeeds by testing its return value (it ...