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Diffstat (limited to 'src/declarative/util/qbindablemap.cpp')
| -rw-r--r-- | src/declarative/util/qbindablemap.cpp | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/src/declarative/util/qbindablemap.cpp b/src/declarative/util/qbindablemap.cpp new file mode 100644 index 0000000..aea2a2c --- /dev/null +++ b/src/declarative/util/qbindablemap.cpp @@ -0,0 +1,179 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the QtDeclarative module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qbindablemap.h" +#include <qmlopenmetaobject.h> +#include <QDebug> + +QT_BEGIN_NAMESPACE + +//QBindableMapMetaObject lets us listen for changes coming from QML +//so we can emit the changed signal. +class QBindableMapMetaObject : public QmlOpenMetaObject +{ +public: + QBindableMapMetaObject(QBindableMap *obj) : QmlOpenMetaObject(obj) + { + map = obj; + } + +protected: + virtual void propertyWrite(int index) + { + map->emitChanged(QLatin1String(name(index))); + } + +private: + QBindableMap *map; +}; + +/*! + \class QBindableMap + \brief The QBindableMap class allows you to set key-value pairs that can be used in bindings. + + QBindableMap provides a convenient way to expose domain data to the UI layer. + The following example shows how you might declare data in C++ and then + access it in QML. + + Setup in C++: + \code + //create our data + QBindableMap ownerData; + ownerData.setValue("name", QVariant(QString("John Smith"))); + ownerData.setValue("phone", QVariant(QString("555-5555"))); + + //expose it to the UI layer + QmlContext *ctxt = view->bindContext(); + ctxt->setProperty("owner", &data); + \endcode + + Then, in QML: + \code + <Text text="{owner.name}"/> + <Text text="{owner.phone}"/> + \endcode + + The binding is dynamic - whenever a key's value is updated, anything bound to that + key will be updated as well. + + To detect value changes made in the UI layer you can connect to the changed() signal. + However, note that changed() is \b NOT emitted when changes are made by calling setValue() + or clearValue() - it is only emitted when a value is updated from QML. +*/ + +// is there a more efficient way to store/return keys? +// (or should we just provide an iterator or something else instead?) +// can we provide a way to clear keys? +// do we want to make any claims regarding key ordering? +// should we have signals for insertion and and deletion -- becoming more model like +// should we emit change for our own changes as well? +// Bug or Feature?: values can be created in QML (owner.somethingElse = "Hello") will create somethingElse property. (need to verify if this is actually the case) +// Bug or Feature?: all values are read-write (there are no read-only values) + +/*! + Constructs a bindable map with parent object \a parent. +*/ +QBindableMap::QBindableMap(QObject *parent) +: QObject(parent) +{ + m_mo = new QBindableMapMetaObject(this); +} + +QBindableMap::~QBindableMap() +{ +} + +/*! + Clears the value (if any) associated with \a key. +*/ +void QBindableMap::clearValue(const QString &key) +{ + //m_keys.remove(); //### + m_mo->setValue(key.toLatin1(), QVariant()); + //emit changed(key); +} + +/*! + Returns the value associated with \a key. + + If no value has been set for this key (or if the value has been cleared), + an invalid QVariant is returned. +*/ +QVariant QBindableMap::value(const QString &key) const +{ + return m_mo->value(key.toLatin1()); +} + +/*! + Sets the value associated with \a key to \a value. + + If the key doesn't exist, it is automatically created. +*/ +void QBindableMap::setValue(const QString &key, QVariant value) +{ + if (!m_keys.contains(key)) + m_keys.append(key); + m_mo->setValue(key.toLatin1(), value); + //emit changed(key); +} + +/*! + Returns the list of keys. + + Keys that have been cleared will still appear in this list, even though their + associated values are invalid QVariants. +*/ +QStringList QBindableMap::keys() const +{ + return m_keys; +} + +/*! + \fn void QBindableMap::changed(const QString &key) + This signal is emitted whenever one of the values in the map is changed. \a key + is the key corresponding to the value that was changed. + */ + +void QBindableMap::emitChanged(const QString &key) +{ + emit changed(key); +} +QT_END_NAMESPACE |