From 2e7cfca6089a0923698b9cd208f79a660e058caa Mon Sep 17 00:00:00 2001 From: Bea Lam Date: Mon, 6 Dec 2010 17:49:17 +1000 Subject: Document support for QVariantList and QVariantMap type conversion --- doc/src/declarative/qtbinding.qdoc | 34 ++++++++++- .../qtbinding/variantlistmap/MyItem.qml | 54 +++++++++++++++++ .../declarative/qtbinding/variantlistmap/main.cpp | 67 ++++++++++++++++++++++ .../qtbinding/variantlistmap/variantlistmap.pro | 2 + 4 files changed, 156 insertions(+), 1 deletion(-) create mode 100644 doc/src/snippets/declarative/qtbinding/variantlistmap/MyItem.qml create mode 100644 doc/src/snippets/declarative/qtbinding/variantlistmap/main.cpp create mode 100644 doc/src/snippets/declarative/qtbinding/variantlistmap/variantlistmap.pro diff --git a/doc/src/declarative/qtbinding.qdoc b/doc/src/declarative/qtbinding.qdoc index 71f41bc..04b8ca6 100644 --- a/doc/src/declarative/qtbinding.qdoc +++ b/doc/src/declarative/qtbinding.qdoc @@ -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++. diff --git a/doc/src/snippets/declarative/qtbinding/variantlistmap/MyItem.qml b/doc/src/snippets/declarative/qtbinding/variantlistmap/MyItem.qml new file mode 100644 index 0000000..dd59fed --- /dev/null +++ b/doc/src/snippets/declarative/qtbinding/variantlistmap/MyItem.qml @@ -0,0 +1,54 @@ +/**************************************************************************** +** +** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor +** the names of its contributors may be used to endorse or promote +** products derived from this software without specific prior written +** permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** $QT_END_LICENSE$ +** +****************************************************************************/ +import QtQuick 1.0 + +//![0] +// MyItem.qml +Item { + function readValues(anArray, anObject) { + for (var i=0; i +#include + +int main(int argc, char *argv[]) { + QApplication app(argc, argv); + +//![0] +// C++ +QDeclarativeView view(QUrl::fromLocalFile("MyItem.qml")); + +QVariantList list; +list << 10 << Qt::green << "bottles"; + +QVariantMap map; +map.insert("language", "QML"); +map.insert("released", QDate(2010, 9, 21)); + +QMetaObject::invokeMethod(view.rootObject(), "readValues", + Q_ARG(QVariant, QVariant::fromValue(list)), + Q_ARG(QVariant, QVariant::fromValue(map))); +//![0] + + view.setSource(QUrl::fromLocalFile("MyItem.qml")); + view.show(); + + return app.exec(); +} + diff --git a/doc/src/snippets/declarative/qtbinding/variantlistmap/variantlistmap.pro b/doc/src/snippets/declarative/qtbinding/variantlistmap/variantlistmap.pro new file mode 100644 index 0000000..68eeaf2 --- /dev/null +++ b/doc/src/snippets/declarative/qtbinding/variantlistmap/variantlistmap.pro @@ -0,0 +1,2 @@ +QT += declarative +SOURCES += main.cpp -- cgit v0.12