diff options
Diffstat (limited to 'doc/src/declarative/qtbinding.qdoc')
| -rw-r--r-- | doc/src/declarative/qtbinding.qdoc | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/doc/src/declarative/qtbinding.qdoc b/doc/src/declarative/qtbinding.qdoc index c3ce6d0..04b8ca6 100644 --- a/doc/src/declarative/qtbinding.qdoc +++ b/doc/src/declarative/qtbinding.qdoc @@ -230,7 +230,7 @@ Also see the QDeclarativeContext documentation for more information. \section2 Defining new QML elements -While new QML elements can be \l {Defining new Components}{defined in QML}, they can also be +While new QML elements can be \l {Defining New Components}{defined in QML}, they can also be defined by C++ classes; in fact, many of the core \l {QML Elements} are implemented through C++ classes. When you create a QML object using one of these elements, you are simply creating an instance of a QObject-based C++ class and setting its properties. @@ -426,6 +426,7 @@ By default, QML recognizes the following data types: \o QSize, QSizeF \o QRect, QRectF \o QVariant +\o QVariantList, QVariantMap \o QObject* \o Enumerations declared with Q_ENUMS() \endlist @@ -434,6 +435,37 @@ To allow a custom C++ type to be created or used in QML, the C++ class must be r type using qmlRegisterType(), as shown in the \l {Defining new QML elements} section above. +\section2 JavaScript arrays and objects + +There is built-in support for automatic type conversion between QVariantList and JavaScript +arrays, and QVariantMap and JavaScript objects. + +For example, the function defined in QML below left expects two arguments, an array and an object, and prints +their contents using the standard JavaScript syntax for array and object item access. The C++ code +below right calls this function, passing a QVariantList and a QVariantMap, which are automatically +converted to JavaScript array and object values, repectively: + +\table +\row +\o \snippet doc/src/snippets/declarative/qtbinding/variantlistmap/MyItem.qml 0 +\o \snippet doc/src/snippets/declarative/qtbinding/variantlistmap/main.cpp 0 +\endtable + +This produces output like: + +\code +Array item: 10 +Array item: #00ff00 +Array item: bottles +Object item: language = QML +Object item: released = Tue Sep 21 2010 00:00:00 GMT+1000 (EST) +\endcode + +Similarly, if a C++ type uses a QVariantList or QVariantMap type for a property or method +parameter, the value can be created as a JavaScript array or object in the QML +side, and is automatically converted to a QVariantList or QVariantMap when it is passed to C++. + + \section2 Using enumerations of a custom type To use an enumeration from a custom C++ component, the enumeration must be declared with Q_ENUMS() to @@ -455,7 +487,7 @@ See the \l {Tutorial: Writing QML extensions with C++}{Writing QML extensions wi the \l {Extending QML in C++} reference documentation for more information. -\section2 Automatic type conversion +\section2 Automatic type conversion from strings As a convenience, some basic types can be specified in QML using format strings to make it easier to pass simple values from QML to C++. |