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Diffstat (limited to 'doc/src/declarative/qtbinding.qdoc')
-rw-r--r-- | doc/src/declarative/qtbinding.qdoc | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/doc/src/declarative/qtbinding.qdoc b/doc/src/declarative/qtbinding.qdoc index 2909f2e..ffef345 100644 --- a/doc/src/declarative/qtbinding.qdoc +++ b/doc/src/declarative/qtbinding.qdoc @@ -225,6 +225,101 @@ binding that does not have a NOTIFY signal will cause QML to issue a warning at If an application is too dynamic to structure data as compile-time QObject types, dynamically structured data can be constructed at runtime using the QmlPropertyMap class. + +\section1 Calling C++ methods from QML + +It is possible to call methods of QObject derived types by either exposing the +methods as public slots, or by marking the methods Q_INVOKABLE. + +The C++ methods can also have parameters and return values. QML has support for +the following types: + +\list +\o bool +\o unsigned int, int +\o float, double, qreal +\o QString +\o QUrl +\o QColor +\o QDate, QTime, QDateTime +\o QPoint, QPointF +\o QSize, QSizeF +\o QRect, QRectF +\o QVariant +\endlist + +This example toggles the "LED Blinker" when the MouseRegion is clicked: + +\table +\row +\o +\code +// main.cpp +class LEDBlinker : public QObject +{ + Q_OBJECT +public: + LEDBlinker(); + + Q_INVOKABLE bool isRunning(); + +public slots: + void start(); + void stop(); +}; + +int main(int argc, char **argv) +{ + // ... + + QmlContext *context = engine->rootContext(); + context->setContextProperty("ledBlinker", new LEDBlinker); + + // ... +} +\endcode +\o +\code +// main.qml +import Qt 4.6 + +Rectangle { + MouseRegion { + anchors.fill: parent + onClicked: { + if (ledBlinker.isRunning()) + ledBlinker.stop() + else + ledBlicker.start(); + } + } +} +\endcode +\endtable + +Note that in this particular example a better way to achieve the same result +is to have a "running" property. This leads to much nicer QML code: + +\table +\row +\o +\code +// main.qml +import Qt 4.6 + +Rectangle { + MouseRegion { + anchors.fill: parent + onClicked: ledBlinker.running = !ledBlinker.running + } +} +\endcode +\endtable + + +Of course, it is also possible to call \l {Adding new methods}{functions declared in QML from C++}. + + \section1 Network Components If the URL passed to QmlComponent is a network resource, or if the QML document references a |