QDeclarativeEngine Class Reference

 QDeclarativeEngine engine;
 QDeclarativeComponent component(&engine);
 component.setData("import QtQuick 1.0\nText { text: \"Hello world!\" }", QUrl());
 QDeclarativeItem *item = qobject_cast<QDeclarativeItem *>(component.create());

 //add item to view, etc
 ...

Member Function Documentation

QDeclarativeEngine::QDeclarativeEngine ( QObject * parent = 0 )

Create a new QDeclarativeEngine with the given parent.

QDeclarativeEngine::~QDeclarativeEngine () [virtual]

Destroys the QDeclarativeEngine.

Any QDeclarativeContext's created on this engine will be invalidated, but not destroyed (unless they are parented to the QDeclarativeEngine object).

void QDeclarativeEngine::addImageProvider ( const QString & providerId, QDeclarativeImageProvider * provider )

Sets the provider to use for images requested via the image: url scheme, with host providerId. The QDeclarativeEngine takes ownership of provider.

Image providers enable support for pixmap and threaded image requests. See the QDeclarativeImageProvider documentation for details on implementing and using image providers.

All required image providers should be added to the engine before any QML sources files are loaded.

See also removeImageProvider().

void QDeclarativeEngine::addImportPath ( const QString & path )

Adds path as a directory where the engine searches for installed modules in a URL-based directory structure. The path may be a local filesystem directory or a URL.

The newly added path will be first in the importPathList().

See also setImportPathList() and QML Modules.

void QDeclarativeEngine::addPluginPath ( const QString & path )

Adds path as a directory where the engine searches for native plugins for imported modules (referenced in the qmldir file).

By default, the list contains only ., i.e. the engine searches in the directory of the qmldir file itself.

The newly added path will be first in the pluginPathList().

See also setPluginPathList().

QUrl QDeclarativeEngine::baseUrl () const

Return the base URL for this engine. The base URL is only used to resolve components when a relative URL is passed to the QDeclarativeComponent constructor.

If a base URL has not been explicitly set, this method returns the application's current working directory.

See also setBaseUrl().

void QDeclarativeEngine::clearComponentCache ()

Clears the engine's internal component cache.

Normally the QDeclarativeEngine caches components loaded from qml files. This method clears this cache and forces the component to be reloaded.

QDeclarativeContext * QDeclarativeEngine::contextForObject ( const QObject * object ) [static]

Returns the QDeclarativeContext for the object, or 0 if no context has been set.

When the QDeclarativeEngine instantiates a QObject, the context is set automatically.

See also setContextForObject().

QDeclarativeImageProvider * QDeclarativeEngine::imageProvider ( const QString & providerId ) const

Returns the QDeclarativeImageProvider set for providerId.

QStringList QDeclarativeEngine::importPathList () const

Returns the list of directories where the engine searches for installed modules in a URL-based directory structure.

For example, if /opt/MyApp/lib/imports is in the path, then QML that imports com.mycompany.Feature will cause the QDeclarativeEngine to look in /opt/MyApp/lib/imports/com/mycompany/Feature/ for the components provided by that module. A qmldir file is required for defining the type version mapping and possibly declarative extensions plugins.

By default, the list contains the directory of the application executable, paths specified in the QML_IMPORT_PATH environment variable, and the builtin ImportsPath from QLibraryInfo.

See also addImportPath() and setImportPathList().

bool QDeclarativeEngine::importPlugin ( const QString & filePath, const QString & uri, QString * errorString )

Imports the plugin named filePath with the uri provided. Returns true if the plugin was successfully imported; otherwise returns false.

On failure and if non-null, *errorString will be set to a message describing the failure.

The plugin has to be a Qt plugin which implements the QDeclarativeExtensionPlugin interface.

QNetworkAccessManager * QDeclarativeEngine::networkAccessManager () const

Returns a common QNetworkAccessManager which can be used by any QML element instantiated by this engine.

If a QDeclarativeNetworkAccessManagerFactory has been set and a QNetworkAccessManager has not yet been created, the QDeclarativeNetworkAccessManagerFactory will be used to create the QNetworkAccessManager; otherwise the returned QNetworkAccessManager will have no proxy or cache set.

See also setNetworkAccessManagerFactory().

QDeclarativeNetworkAccessManagerFactory * QDeclarativeEngine::networkAccessManagerFactory () const

Returns the current QDeclarativeNetworkAccessManagerFactory.

See also setNetworkAccessManagerFactory().

ObjectOwnership QDeclarativeEngine::objectOwnership ( QObject * object ) [static]

Returns the ownership of object.

See also setObjectOwnership().

bool QDeclarativeEngine::outputWarningsToStandardError () const

Returns true if warning messages will be output to stderr in addition to being emitted by the warnings() signal, otherwise false.

The default value is true.

See also setOutputWarningsToStandardError().

QStringList QDeclarativeEngine::pluginPathList () const

Returns the list of directories where the engine searches for native plugins for imported modules (referenced in the qmldir file).

By default, the list contains only ., i.e. the engine searches in the directory of the qmldir file itself.

See also addPluginPath() and setPluginPathList().

void QDeclarativeEngine::quit () [signal]

This signal is emitted when the QML loaded by the engine would like to quit.

void QDeclarativeEngine::removeImageProvider ( const QString & providerId )

Removes the QDeclarativeImageProvider for providerId.

Returns the provider if it was found; otherwise returns 0.

See also addImageProvider().

QDeclarativeContext * QDeclarativeEngine::rootContext () const

Returns the engine's root context.

The root context is automatically created by the QDeclarativeEngine. Data that should be available to all QML component instances instantiated by the engine should be put in the root context.

Additional data that should only be available to a subset of component instances should be added to sub-contexts parented to the root context.

void QDeclarativeEngine::setBaseUrl ( const QUrl & url )

Set the base URL for this engine to url.

See also baseUrl().

void QDeclarativeEngine::setContextForObject ( QObject * object, QDeclarativeContext * context ) [static]

Sets the QDeclarativeContext for the object to context. If the object already has a context, a warning is output, but the context is not changed.

When the QDeclarativeEngine instantiates a QObject, the context is set automatically.

See also contextForObject().

void QDeclarativeEngine::setImportPathList ( const QStringList & paths )

Sets paths as the list of directories where the engine searches for installed modules in a URL-based directory structure.

By default, the list contains the directory of the application executable, paths specified in the QML_IMPORT_PATH environment variable, and the builtin ImportsPath from QLibraryInfo.

See also importPathList() and addImportPath().

void QDeclarativeEngine::setNetworkAccessManagerFactory ( QDeclarativeNetworkAccessManagerFactory * factory )

Sets the factory to use for creating QNetworkAccessManager(s).

QNetworkAccessManager is used for all network access by QML. By implementing a factory it is possible to create custom QNetworkAccessManager with specialized caching, proxy and cookie support.

The factory must be set before executing the engine.

See also networkAccessManagerFactory().

void QDeclarativeEngine::setObjectOwnership ( QObject * object, ObjectOwnership ownership ) [static]

Sets the ownership of object.

See also objectOwnership().

void QDeclarativeEngine::setOutputWarningsToStandardError ( bool enabled )

Set whether warning messages will be output to stderr to enabled.

If enabled is true, any warning messages generated by QML will be output to stderr and emitted by the warnings() signal. If enabled is false, on the warnings() signal will be emitted. This allows applications to handle warning output themselves.

The default value is true.

See also outputWarningsToStandardError().

void QDeclarativeEngine::setPluginPathList ( const QStringList & paths )

Sets the list of directories where the engine searches for native plugins for imported modules (referenced in the qmldir file) to paths.

By default, the list contains only ., i.e. the engine searches in the directory of the qmldir file itself.

See also pluginPathList() and addPluginPath().

void QDeclarativeEngine::warnings ( const QList<QDeclarativeError> & warnings ) [signal]

This signal is emitted when warnings messages are generated by QML.

 qmlInfo(object) << tr("component property is a write-once property");

 QML MyCustomType (unknown location): component property is a write-once property

 template<typename T>
 int qmlRegisterType(const char *uri, int versionMajor, int versionMinor, const char *qmlName);

 template<typename T, int metaObjectRevision>
 int qmlRegisterType(const char *uri, int versionMajor, int versionMinor, const char *qmlName);

 #include <QtDeclarative>

 ...

 qmlRegisterType<MySliderItem>("com.mycompany.qmlcomponents", 1, 0, "Slider");

 import com.mycompany.qmlcomponents 1.0

 Slider {
     // ...
 }

 #ifdef NO_GAMES_ALLOWED
 qmlRegisterTypeNotAvailable("MinehuntCore", 0, 1, "Game", "Get back to work, slacker!");
 #else
 qmlRegisterType<MinehuntGame>("MinehuntCore", 0, 1, "Game");
 #endif

 fun.qml: Get back to work, slacker!
    Game {
    ^