diff options
Diffstat (limited to 'src/qml/doc/src/cppintegration/extending-tutorial.qdoc')
| -rw-r--r-- | src/qml/doc/src/cppintegration/extending-tutorial.qdoc | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/src/qml/doc/src/cppintegration/extending-tutorial.qdoc b/src/qml/doc/src/cppintegration/extending-tutorial.qdoc index d587173e5a..458768bf18 100644 --- a/src/qml/doc/src/cppintegration/extending-tutorial.qdoc +++ b/src/qml/doc/src/cppintegration/extending-tutorial.qdoc @@ -103,11 +103,22 @@ functionality of an existing QObject-based class, it could inherit from that cla Alternatively, if we want to create a visual item that doesn't need to perform drawing operations with the QPainter API, we can just subclass QQuickItem. -The \c PieChart class defines the two properties, \c name and \c color, with the Q_PROPERTY macro, -and overrides QQuickPaintedItem::paint(). The class implementation in \c piechart.cpp -simply sets and returns the \c m_name and \c m_color values as appropriate, and -implements \c paint() to draw a simple pie chart. It also turns off the -QGraphicsItem::ItemHasNoContents flag to enable painting: +The \c PieChart class defines the two properties, \c name and \c color, with the +Q_PROPERTY macro, and overrides QQuickPaintedItem::paint(). The \c PieChart +class is registered using the QML_ELEMENT macro, to allow it to be used from +QML. If you don't register the class, \c app.qml won't be able to create a +\c PieChart. + +For the registration to take effect, the \c qmltypes option is added to +\c CONFIG in the project file and a \c QML_IMPORT_NAME and +\c QML_IMPORT_MAJOR_VERSION are given: + +\snippet tutorials/extending-qml/chapter1-basics/chapter1-basics.pro 0 + +The class implementation in \c piechart.cpp simply sets and returns the +\c m_name and \c m_color values as appropriate, and implements \c paint() to +draw a simple pie chart. It also turns off the QGraphicsItem::ItemHasNoContents +flag to enable painting: \snippet tutorials/extending-qml/chapter1-basics/piechart.cpp 0 \dots 0 @@ -125,9 +136,7 @@ provided for various other \l {QML Basic Types}{basic types}; for example, a str like "640x480" can be automatically converted to a QSize value. We'll also create a C++ application that uses a QQuickView to run and -display \c app.qml. The application must register the \c PieChart type -using the qmlRegisterType() function, to allow it to be used from QML. If -you don't register the type, \c app.qml won't be able to create a \c PieChart. +display \c app.qml. Here is the application \c main.cpp: @@ -143,7 +152,7 @@ Now we can build and run the application: \image extending-tutorial-chapter1.png -\note You may see a warning \e {Expression ... depends on non-NOTIFYable properties: +\note You may see a warning \e {Expression ... depends on non-NOTIFYable properties: PieChart::name}. This happens because we add a binding to the writable \c name property, but haven't yet defined a notify signal for it. The QML engine therefore cannot update the binding if the \c name value changes. This is addressed in @@ -450,7 +459,7 @@ In this tutorial, we've shown the basic steps for creating a QML extension: \list \li Define new QML types by subclassing QObject and registering them with - qmlRegisterType() + QML_ELEMENT or QML_NAMED_ELEMENT() \li Add callable methods using \l Q_INVOKABLE or Qt slots, and connect to Qt signals with an \c onSignal syntax \li Add property bindings by defining \l{Qt's Property System}{NOTIFY} signals |