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Diffstat (limited to 'src/declarative/graphicsitems/qdeclarativeloader.cpp')
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diff --git a/src/declarative/graphicsitems/qdeclarativeloader.cpp b/src/declarative/graphicsitems/qdeclarativeloader.cpp new file mode 100644 index 0000000000..6c1f1be0c2 --- /dev/null +++ b/src/declarative/graphicsitems/qdeclarativeloader.cpp @@ -0,0 +1,597 @@ +/**************************************************************************** +** +** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (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 Technology Preview License Agreement accompanying +** this package. +** +** 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 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "private/qdeclarativeloader_p_p.h" + +#include <qdeclarativeinfo.h> +#include <qdeclarativeengine_p.h> +#include <qdeclarativeglobal_p.h> + +QT_BEGIN_NAMESPACE + +QDeclarativeLoaderPrivate::QDeclarativeLoaderPrivate() + : item(0), component(0), ownComponent(false), updatingSize(false), + itemWidthValid(false), itemHeightValid(false) +{ +} + +QDeclarativeLoaderPrivate::~QDeclarativeLoaderPrivate() +{ +} + +void QDeclarativeLoaderPrivate::itemGeometryChanged(QDeclarativeItem *resizeItem, const QRectF &newGeometry, const QRectF &oldGeometry) +{ + if (resizeItem == item) { + if (!updatingSize && newGeometry.width() != oldGeometry.width()) + itemWidthValid = true; + if (!updatingSize && newGeometry.height() != oldGeometry.height()) + itemHeightValid = true; + _q_updateSize(false); + } + QDeclarativeItemChangeListener::itemGeometryChanged(resizeItem, newGeometry, oldGeometry); +} + +void QDeclarativeLoaderPrivate::clear() +{ + if (ownComponent) { + component->deleteLater(); + component = 0; + ownComponent = false; + } + source = QUrl(); + + if (item) { + if (QDeclarativeItem *qmlItem = qobject_cast<QDeclarativeItem*>(item)) { + QDeclarativeItemPrivate *p = + static_cast<QDeclarativeItemPrivate *>(QGraphicsItemPrivate::get(qmlItem)); + p->removeItemChangeListener(this, QDeclarativeItemPrivate::Geometry); + } + + // We can't delete immediately because our item may have triggered + // the Loader to load a different item. + if (item->scene()) { + item->scene()->removeItem(item); + } else { + item->setParentItem(0); + item->setVisible(false); + } + item->deleteLater(); + item = 0; + } +} + +void QDeclarativeLoaderPrivate::initResize() +{ + Q_Q(QDeclarativeLoader); + if (QDeclarativeItem *qmlItem = qobject_cast<QDeclarativeItem*>(item)) { + QDeclarativeItemPrivate *p = + static_cast<QDeclarativeItemPrivate *>(QGraphicsItemPrivate::get(qmlItem)); + p->addItemChangeListener(this, QDeclarativeItemPrivate::Geometry); + // We may override the item's size, so we need to remember + // whether the item provided its own valid size. + itemWidthValid = p->widthValid; + itemHeightValid = p->heightValid; + } else if (item && item->isWidget()) { + QGraphicsWidget *widget = static_cast<QGraphicsWidget*>(item); + widget->installEventFilter(q); + } + _q_updateSize(); +} + +/*! + \qmlclass Loader QDeclarativeLoader + \ingroup qml-utility-elements + \since 4.7 + \inherits Item + + \brief The Loader item allows dynamically loading an Item-based + subtree from a URL or Component. + + Loader is used to dynamically load visual QML components. It can load a + QML file (using the \l source property) or a \l Component object (using + the \l sourceComponent property). It is useful for delaying the creation + of a component until it is required: for example, when a component should + be created on demand, or when a component should not be created + unnecessarily for performance reasons. + + Here is a Loader that loads "Page1.qml" as a component when the + \l MouseArea is clicked: + + \snippet doc/src/snippets/declarative/loader/simple.qml 0 + + The loaded item can be accessed using the \l item property. + + If the \l source or \l sourceComponent changes, any previously instantiated + items are destroyed. Setting \l source to an empty string or setting + \l sourceComponent to \c undefined destroys the currently loaded item, + freeing resources and leaving the Loader empty. + + \section2 Loader sizing behavior + + Loader is like any other visual item and must be positioned and sized + accordingly to become visible. + + \list + \o If an explicit size is not specified for the Loader, the Loader + is automatically resized to the size of the loaded item once the + component is loaded. + \o If the size of the Loader is specified explicitly by setting + the width, height or by anchoring, the loaded item will be resized + to the size of the Loader. + \endlist + + In both scenarios the size of the item and the Loader are identical. + This ensures that anchoring to the Loader is equivalent to anchoring + to the loaded item. + + \table + \row + \o sizeloader.qml + \o sizeitem.qml + \row + \o \snippet doc/src/snippets/declarative/loader/sizeloader.qml 0 + \o \snippet doc/src/snippets/declarative/loader/sizeitem.qml 0 + \row + \o The red rectangle will be sized to the size of the root item. + \o The red rectangle will be 50x50, centered in the root item. + \endtable + + + \section2 Receiving signals from loaded items + + Any signals emitted from the loaded item can be received using the + \l Connections element. For example, the following \c application.qml + loads \c MyItem.qml, and is able to receive the \c message signal from + the loaded item through a \l Connections object: + + \table + \row + \o application.qml + \o MyItem.qml + \row + \o \snippet doc/src/snippets/declarative/loader/connections.qml 0 + \o \snippet doc/src/snippets/declarative/loader/MyItem.qml 0 + \endtable + + Alternatively, since \c MyItem.qml is loaded within the scope of the + Loader, it could also directly call any function defined in the Loader or + its parent \l Item. + + + \section2 Focus and key events + + Loader is a focus scope. Its \l {Item::}{focus} property must be set to + \c true for any of its children to get the \e {active focus}. (See + \l{qmlfocus#Acquiring Focus and Focus Scopes}{the focus documentation page} + for more details.) Any key events received in the loaded item should likely + also be \l {KeyEvent::}{accepted} so they are not propagated to the Loader. + + For example, the following \c application.qml loads \c KeyReader.qml when + the \l MouseArea is clicked. Notice the \l {Item::}{focus} property is + set to \c true for the Loader as well as the \l Item in the dynamically + loaded object: + + \table + \row + \o application.qml + \o KeyReader.qml + \row + \o \snippet doc/src/snippets/declarative/loader/focus.qml 0 + \o \snippet doc/src/snippets/declarative/loader/KeyReader.qml 0 + \endtable + + Once \c KeyReader.qml is loaded, it accepts key events and sets + \c event.accepted to \c true so that the event is not propagated to the + parent \l Rectangle. + + \sa {dynamic-object-creation}{Dynamic Object Creation} +*/ + +QDeclarativeLoader::QDeclarativeLoader(QDeclarativeItem *parent) + : QDeclarativeImplicitSizeItem(*(new QDeclarativeLoaderPrivate), parent) +{ + Q_D(QDeclarativeLoader); + d->flags |= QGraphicsItem::ItemIsFocusScope; +} + +QDeclarativeLoader::~QDeclarativeLoader() +{ + Q_D(QDeclarativeLoader); + if (d->item) { + if (QDeclarativeItem *qmlItem = qobject_cast<QDeclarativeItem*>(d->item)) { + QDeclarativeItemPrivate *p = + static_cast<QDeclarativeItemPrivate *>(QGraphicsItemPrivate::get(qmlItem)); + p->removeItemChangeListener(d, QDeclarativeItemPrivate::Geometry); + } + } +} + +/*! + \qmlproperty url Loader::source + This property holds the URL of the QML component to instantiate. + + Note the QML component must be an \l{Item}-based component. The loader + cannot load non-visual components. + + To unload the currently loaded item, set this property to an empty string, + or set \l sourceComponent to \c undefined. Setting \c source to a + new URL will also cause the item created by the previous URL to be unloaded. + + \sa sourceComponent, status, progress +*/ +QUrl QDeclarativeLoader::source() const +{ + Q_D(const QDeclarativeLoader); + return d->source; +} + +void QDeclarativeLoader::setSource(const QUrl &url) +{ + Q_D(QDeclarativeLoader); + if (d->source == url) + return; + + d->clear(); + + d->source = url; + + if (d->source.isEmpty()) { + emit sourceChanged(); + emit statusChanged(); + emit progressChanged(); + emit itemChanged(); + return; + } + + d->component = new QDeclarativeComponent(qmlEngine(this), d->source, this); + d->ownComponent = true; + + if (isComponentComplete()) + d->load(); +} + +/*! + \qmlproperty Component Loader::sourceComponent + This property holds the \l{Component} to instantiate. + + \qml + Item { + Component { + id: redSquare + Rectangle { color: "red"; width: 10; height: 10 } + } + + Loader { sourceComponent: redSquare } + Loader { sourceComponent: redSquare; x: 10 } + } + \endqml + + To unload the currently loaded item, set this property to an empty string + or \c undefined. + + \sa source, progress +*/ + +QDeclarativeComponent *QDeclarativeLoader::sourceComponent() const +{ + Q_D(const QDeclarativeLoader); + return d->component; +} + +void QDeclarativeLoader::setSourceComponent(QDeclarativeComponent *comp) +{ + Q_D(QDeclarativeLoader); + if (comp == d->component) + return; + + d->clear(); + + d->component = comp; + d->ownComponent = false; + + if (!d->component) { + emit sourceChanged(); + emit statusChanged(); + emit progressChanged(); + emit itemChanged(); + return; + } + + if (isComponentComplete()) + d->load(); +} + +void QDeclarativeLoader::resetSourceComponent() +{ + setSourceComponent(0); +} + +void QDeclarativeLoaderPrivate::load() +{ + Q_Q(QDeclarativeLoader); + + if (!q->isComponentComplete() || !component) + return; + + if (!component->isLoading()) { + _q_sourceLoaded(); + } else { + QObject::connect(component, SIGNAL(statusChanged(QDeclarativeComponent::Status)), + q, SLOT(_q_sourceLoaded())); + QObject::connect(component, SIGNAL(progressChanged(qreal)), + q, SIGNAL(progressChanged())); + emit q->statusChanged(); + emit q->progressChanged(); + emit q->sourceChanged(); + emit q->itemChanged(); + } +} + +void QDeclarativeLoaderPrivate::_q_sourceLoaded() +{ + Q_Q(QDeclarativeLoader); + + if (component) { + if (!component->errors().isEmpty()) { + QDeclarativeEnginePrivate::warning(qmlEngine(q), component->errors()); + emit q->sourceChanged(); + emit q->statusChanged(); + emit q->progressChanged(); + return; + } + + QDeclarativeContext *creationContext = component->creationContext(); + if (!creationContext) creationContext = qmlContext(q); + QDeclarativeContext *ctxt = new QDeclarativeContext(creationContext); + ctxt->setContextObject(q); + + QDeclarativeGuard<QDeclarativeComponent> c = component; + QObject *obj = component->beginCreate(ctxt); + if (component != c) { + // component->create could trigger a change in source that causes + // component to be set to something else. In that case we just + // need to cleanup. + if (c) + c->completeCreate(); + delete obj; + delete ctxt; + return; + } + if (obj) { + item = qobject_cast<QGraphicsObject *>(obj); + if (item) { + QDeclarative_setParent_noEvent(ctxt, obj); + QDeclarative_setParent_noEvent(item, q); + item->setParentItem(q); +// item->setFocus(true); + initResize(); + } else { + qmlInfo(q) << QDeclarativeLoader::tr("Loader does not support loading non-visual elements."); + delete obj; + delete ctxt; + } + } else { + if (!component->errors().isEmpty()) + QDeclarativeEnginePrivate::warning(qmlEngine(q), component->errors()); + delete obj; + delete ctxt; + source = QUrl(); + } + component->completeCreate(); + emit q->sourceChanged(); + emit q->statusChanged(); + emit q->progressChanged(); + emit q->itemChanged(); + emit q->loaded(); + } +} + +/*! + \qmlproperty enumeration Loader::status + + This property holds the status of QML loading. It can be one of: + \list + \o Loader.Null - no QML source has been set + \o Loader.Ready - the QML source has been loaded + \o Loader.Loading - the QML source is currently being loaded + \o Loader.Error - an error occurred while loading the QML source + \endlist + + Use this status to provide an update or respond to the status change in some way. + For example, you could: + + \list + \o Trigger a state change: + \qml + State { name: 'loaded'; when: loader.status == Loader.Ready } + \endqml + + \o Implement an \c onStatusChanged signal handler: + \qml + Loader { + id: loader + onStatusChanged: if (loader.status == Loader.Ready) console.log('Loaded') + } + \endqml + + \o Bind to the status value: + \qml + Text { text: loader.status == Loader.Ready ? 'Loaded' : 'Not loaded' } + \endqml + \endlist + + Note that if the source is a local file, the status will initially be Ready (or Error). While + there will be no onStatusChanged signal in that case, the onLoaded will still be invoked. + + \sa progress +*/ + +QDeclarativeLoader::Status QDeclarativeLoader::status() const +{ + Q_D(const QDeclarativeLoader); + + if (d->component) + return static_cast<QDeclarativeLoader::Status>(d->component->status()); + + if (d->item) + return Ready; + + return d->source.isEmpty() ? Null : Error; +} + +void QDeclarativeLoader::componentComplete() +{ + Q_D(QDeclarativeLoader); + + QDeclarativeItem::componentComplete(); + d->load(); +} + + +/*! + \qmlsignal Loader::onLoaded() + + This handler is called when the \l status becomes \c Loader.Ready, or on successful + initial load. +*/ + + +/*! +\qmlproperty real Loader::progress + +This property holds the progress of loading QML data from the network, from +0.0 (nothing loaded) to 1.0 (finished). Most QML files are quite small, so +this value will rapidly change from 0 to 1. + +\sa status +*/ +qreal QDeclarativeLoader::progress() const +{ + Q_D(const QDeclarativeLoader); + + if (d->item) + return 1.0; + + if (d->component) + return d->component->progress(); + + return 0.0; +} + +void QDeclarativeLoaderPrivate::_q_updateSize(bool loaderGeometryChanged) +{ + Q_Q(QDeclarativeLoader); + if (!item || updatingSize) + return; + + updatingSize = true; + if (QDeclarativeItem *qmlItem = qobject_cast<QDeclarativeItem*>(item)) { + if (!itemWidthValid) + q->setImplicitWidth(qmlItem->implicitWidth()); + else + q->setImplicitWidth(qmlItem->width()); + if (loaderGeometryChanged && q->widthValid()) + qmlItem->setWidth(q->width()); + if (!itemHeightValid) + q->setImplicitHeight(qmlItem->implicitHeight()); + else + q->setImplicitHeight(qmlItem->height()); + if (loaderGeometryChanged && q->heightValid()) + qmlItem->setHeight(q->height()); + } else if (item && item->isWidget()) { + QGraphicsWidget *widget = static_cast<QGraphicsWidget*>(item); + QSizeF widgetSize = widget->size(); + q->setImplicitWidth(widgetSize.width()); + if (loaderGeometryChanged && q->widthValid()) + widgetSize.setWidth(q->width()); + q->setImplicitHeight(widgetSize.height()); + if (loaderGeometryChanged && q->heightValid()) + widgetSize.setHeight(q->height()); + if (widget->size() != widgetSize) + widget->resize(widgetSize); + } + updatingSize = false; +} + +/*! + \qmlproperty Item Loader::item + This property holds the top-level item that is currently loaded. +*/ +QGraphicsObject *QDeclarativeLoader::item() const +{ + Q_D(const QDeclarativeLoader); + return d->item; +} + +void QDeclarativeLoader::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeometry) +{ + Q_D(QDeclarativeLoader); + if (newGeometry != oldGeometry) { + d->_q_updateSize(); + } + QDeclarativeItem::geometryChanged(newGeometry, oldGeometry); +} + +QVariant QDeclarativeLoader::itemChange(GraphicsItemChange change, const QVariant &value) +{ + Q_D(QDeclarativeLoader); + if (change == ItemSceneHasChanged) { + if (d->item && d->item->isWidget()) { + d->item->removeEventFilter(this); + d->item->installEventFilter(this); + } + } + return QDeclarativeItem::itemChange(change, value); +} + +bool QDeclarativeLoader::eventFilter(QObject *watched, QEvent *e) +{ + Q_D(QDeclarativeLoader); + if (watched == d->item && e->type() == QEvent::GraphicsSceneResize) { + if (d->item && d->item->isWidget()) + d->_q_updateSize(false); + } + return QDeclarativeItem::eventFilter(watched, e); +} + +#include <moc_qdeclarativeloader_p.cpp> + +QT_END_NAMESPACE |