QQmlApplicationEngine provides a convenient way to load an application from a single QML file. More...

#include <qqmlapplicationengine.h>

Inheritance diagram for QQmlApplicationEngine:

Collaboration diagram for QQmlApplicationEngine:

Public Slots
void	load (const QUrl &url)
	Loads the root QML file located at url.

void	load (const QString &filePath)
	Loads the root QML file located at filePath.

void	loadFromModule (QAnyStringView uri, QAnyStringView typeName)
	Loads the QML type typeName from the module specified by uri.

void	setInitialProperties (const QVariantMap &initialProperties)
	Sets the initialProperties with which the QML component gets initialized after it gets loaded.

void	setExtraFileSelectors (const QStringList &extraFileSelectors)
	Sets the extraFileSelectors to be passed to the internal QQmlFileSelector used for resolving URLs to local files.

void	loadData (const QByteArray &data, const QUrl &url=QUrl())
	Loads the QML given in data.

Public Slots inherited from QQmlEngine
void	retranslate ()
	Refreshes all binding expressions that use strings marked for translation.

Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Signals
void	objectCreated (QObject *object, const QUrl &url)
	This signal is emitted when an object finishes loading.

void	objectCreationFailed (const QUrl &url)

Signals inherited from QQmlEngine
void	offlineStoragePathChanged ()
	This signal is emitted when \l offlineStoragePath changes.

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

void	exit (int retCode)
	This signal is emitted when the QML loaded by the engine would like to exit from the event loop with the specified return code retCode.

void	warnings (const QList< QQmlError > &warnings)
	This signal is emitted when warnings messages are generated by QML.

Signals inherited from QJSEngine
void	uiLanguageChanged ()

Signals inherited from QObject
void	destroyed (QObject *=nullptr)
	This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.

void	objectNameChanged (const QString &objectName, QPrivateSignal)
	This signal is emitted after the object's name has been changed.

Public Member Functions
	QQmlApplicationEngine (QObject *parent=nullptr)
	Create a new QQmlApplicationEngine with the given parent.

	QQmlApplicationEngine (const QUrl &url, QObject *parent=nullptr)
	Create a new QQmlApplicationEngine and loads the QML file at the given url.

	QQmlApplicationEngine (QAnyStringView uri, QAnyStringView typeName, QObject *parent=nullptr)
	Create a new QQmlApplicationEngine and loads the QML type specified by uri and typeName This is provided as a convenience, and is the same as using the empty constructor and calling loadFromModule afterwards.

	QQmlApplicationEngine (const QString &filePath, QObject *parent=nullptr)
	Create a new QQmlApplicationEngine and loads the QML file at the given filePath, which must be a local file path.

	~QQmlApplicationEngine () override
	Destroys the QQmlApplicationEngine and all QML objects it loaded.

QList< QObject * >	rootObjects () const
	Returns a list of all the root objects instantiated by the QQmlApplicationEngine.

Public Member Functions inherited from QQmlEngine
	QQmlEngine (QObject *p=nullptr)
	Create a new QQmlEngine with the given parent.

	~QQmlEngine () override
	Destroys the QQmlEngine.

QQmlContext *	rootContext () const
	Returns the engine's root context.

void	clearComponentCache ()
	Clears the engine's internal component cache.

void	trimComponentCache ()
	Trims the engine's internal component cache.

void	clearSingletons ()
	Clears all singletons the engine owns.

QStringList	importPathList () const
	Returns the list of directories where the engine searches for installed modules in a URL-based directory structure.

void	setImportPathList (const QStringList &paths)
	Sets paths as the list of directories where the engine searches for installed modules in a URL-based directory structure.

void	addImportPath (const QString &dir)
	Adds path as a directory where the engine searches for installed modules in a URL-based directory structure.

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

void	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.

void	addPluginPath (const QString &dir)
	Adds path as a directory where the engine searches for native plugins for imported modules (referenced in the `qmldir` file).

void	addUrlInterceptor (QQmlAbstractUrlInterceptor *urlInterceptor)
	Adds a urlInterceptor to be used when resolving URLs in QML.

void	removeUrlInterceptor (QQmlAbstractUrlInterceptor *urlInterceptor)
	Remove a urlInterceptor that was previously added using \l addUrlInterceptor.

QList< QQmlAbstractUrlInterceptor * >	urlInterceptors () const
	Returns the list of currently active URL interceptors.

QUrl	interceptUrl (const QUrl &url, QQmlAbstractUrlInterceptor::DataType type) const
	Run the current URL interceptors on the given url of the given type and return the result.

void	addImageProvider (const QString &id, QQmlImageProviderBase *)
	Sets the provider to use for images requested via the image: url scheme, with host providerId.

QQmlImageProviderBase *	imageProvider (const QString &id) const
	Returns the image provider set for providerId if found; otherwise returns \nullptr.

void	removeImageProvider (const QString &id)
	Removes the image provider for providerId.

void	setIncubationController (QQmlIncubationController *)
	Sets the engine's incubation controller.

QQmlIncubationController *	incubationController () const
	Returns the currently set incubation controller, or 0 if no controller has been set.

void	setOfflineStoragePath (const QString &dir)

QString	offlineStoragePath () const

QString	offlineStorageDatabaseFilePath (const QString &databaseName) const
	Returns the file path where a \l{QtQuick.LocalStorage}{Local Storage} database with the identifier databaseName is (or would be) located.

QUrl	baseUrl () const
	Return the base URL for this engine.

void	setBaseUrl (const QUrl &)
	Set the base URL for this engine to url.

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

void	setOutputWarningsToStandardError (bool)
	Set whether warning messages will be output to stderr to enabled.

void	markCurrentFunctionAsTranslationBinding ()

template<typename T >
T	singletonInstance (int qmlTypeId)
	\qmlproperty string Qt::uiLanguage

template<typename T >
T	singletonInstance (QAnyStringView moduleName, QAnyStringView typeName)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Returns the instance of a singleton type named typeName from the module specified by uri.

void	captureProperty (QObject *object, const QMetaProperty &property) const

template<>
QJSValue	singletonInstance (int qmlTypeId)

template<>
QJSValue	singletonInstance (QAnyStringView uri, QAnyStringView typeName)

template<>
Q_QML_EXPORT QJSValue	singletonInstance (int qmlTypeId)

template<>
Q_QML_EXPORT QJSValue	singletonInstance (QAnyStringView uri, QAnyStringView typeName)

Public Member Functions inherited from QJSEngine
	QJSEngine ()
	Constructs a QJSEngine object.

	QJSEngine (QObject *parent)
	Constructs a QJSEngine object with the given parent.

	~QJSEngine () override
	Destroys this QJSEngine.

QJSValue	globalObject () const
	Returns this engine's Global Object.

QJSValue	evaluate (const QString &program, const QString &fileName=QString(), int lineNumber=1, QStringList *exceptionStackTrace=nullptr)
	Evaluates program, using lineNumber as the base line number, and returns the result of the evaluation.

QJSValue	importModule (const QString &fileName)
	Imports the module located at fileName and returns a module namespace object that contains all exported variables, constants and functions as properties.

bool	registerModule (const QString &moduleName, const QJSValue &value)
	Registers a QJSValue to serve as a module.

QJSValue	newObject ()
	Creates a JavaScript object of class Object.

QJSValue	newSymbol (const QString &name)

QJSValue	newArray (uint length=0)
	Creates a JavaScript object of class Array with the given length.

QJSValue	newQObject (QObject *object)
	Creates a JavaScript object that wraps the given QObject object, using JavaScriptOwnership.

QJSValue	newQMetaObject (const QMetaObject *metaObject)

template<typename T >
QJSValue	newQMetaObject ()

QJSValue	newErrorObject (QJSValue::ErrorType errorType, const QString &message=QString())

template<typename T >
QJSValue	toScriptValue (const T &value)
	Creates a QJSValue with the given value.

template<typename T >
QJSManagedValue	toManagedValue (const T &value)
	Creates a QJSManagedValue with the given value.

template<typename T >
QJSPrimitiveValue	toPrimitiveValue (const T &value)
	Creates a QJSPrimitiveValue with the given value.

template<typename T >
T	fromScriptValue (const QJSValue &value)
	Returns the given value converted to the template type {T}.

template<typename T >
T	fromManagedValue (const QJSManagedValue &value)
	Returns the given value converted to the template type {T}.

template<typename T >
T	fromPrimitiveValue (const QJSPrimitiveValue &value)
	Returns the given value converted to the template type {T}.

template<typename T >
T	fromVariant (const QVariant &value)
	Returns the given value converted to the template type {T}.

template<typename From , typename To >
To	coerceValue (const From &from)
	Returns the given from converted to the template type {To}.

void	collectGarbage ()
	Runs the garbage collector.

void	installExtensions (Extensions extensions, const QJSValue &object=QJSValue())

void	setInterrupted (bool interrupted)

bool	isInterrupted () const

QV4::ExecutionEngine *	handle () const

void	throwError (const QString &message)
	Throws a run-time error (exception) with the given message.

void	throwError (QJSValue::ErrorType errorType, const QString &message=QString())

void	throwError (const QJSValue &error)

bool	hasError () const
	Returns `true` if the last JavaScript execution resulted in an exception or if throwError() was called.

QJSValue	catchError ()
	If an exception is currently pending, catches it and returns it as a QJSValue.

QString	uiLanguage () const

void	setUiLanguage (const QString &language)

Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)
	Constructs an object with parent object parent.

virtual	~QObject ()
	Destroys the object, deleting all its child objects.

virtual bool	eventFilter (QObject watched, QEvent event)
	Filters events if this object has been installed as an event filter for the watched object.

QString	objectName () const

Q_WEAK_OVERLOAD void	setObjectName (const QString &name)
	Sets the object's name to name.

void	setObjectName (QAnyStringView name)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

QBindable< QString >	bindableObjectName ()

bool	isWidgetType () const
	Returns `true` if the object is a widget; otherwise returns `false`.

bool	isWindowType () const
	Returns `true` if the object is a window; otherwise returns `false`.

bool	isQuickItemType () const
	Returns `true` if the object is a QQuickItem; otherwise returns `false`.

bool	signalsBlocked () const noexcept
	Returns `true` if signals are blocked; otherwise returns `false`.

bool	blockSignals (bool b) noexcept
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).

QThread *	thread () const
	Returns the thread in which the object lives.

bool	moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
	Changes the thread affinity for this object and its children and returns `true` on success.

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
	This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.

int	startTimer (std::chrono::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)

void	killTimer (int id)
	Kills the timer with timer identifier, id.

void	killTimer (Qt::TimerId id)

template<typename T >
T	findChild (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.

template<typename T >
QList< T >	findChildren (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.

template<typename T >
T	findChild (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

template<typename T >
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

const QObjectList &	children () const
	Returns a list of child objects.

void	setParent (QObject *parent)
	Makes the object a child of parent.

void	installEventFilter (QObject *filterObj)
	Installs an event filter filterObj on this object.

void	removeEventFilter (QObject *obj)
	Removes an event filter object obj from this object.

QMetaObject::Connection	connect (const QObject sender, const char signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const

bool	disconnect (const char signal=nullptr, const QObject receiver=nullptr, const char *member=nullptr) const

bool	disconnect (const QObject receiver, const char member=nullptr) const

void	dumpObjectTree () const
	Dumps a tree of children to the debug output.

void	dumpObjectInfo () const
	Dumps information about signal connections, etc.

bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value.

bool	setProperty (const char *name, QVariant &&value)

QVariant	property (const char *name) const
	Returns the value of the object's name property.

QList< QByteArray >	dynamicPropertyNames () const

QBindingStorage *	bindingStorage ()

const QBindingStorage *	bindingStorage () const

QObject *	parent () const
	Returns a pointer to the parent object.

bool	inherits (const char *classname) const
	Returns `true` if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns `false`.

Additional Inherited Members
Public Types inherited from QJSEngine
enum	ObjectOwnership { CppOwnership , JavaScriptOwnership }
	ObjectOwnership controls whether or not the JavaScript memory manager automatically destroys the QObject when the corresponding JavaScript object is garbage collected by the engine. More...

enum	Extension { TranslationExtension = 0x1 , ConsoleExtension = 0x2 , GarbageCollectionExtension = 0x4 , AllExtensions = 0xffffffff }
	This enum is used to specify extensions to be installed via \l installExtensions(). More...

Static Public Member Functions inherited from QQmlEngine
static QQmlContext *	contextForObject (const QObject *)
	Returns the QQmlContext for the object, or nullptr if no context has been set.

static void	setContextForObject (QObject , QQmlContext )
	Sets the QQmlContext for the object to context.

Static Public Member Functions inherited from QJSEngine
static void	setObjectOwnership (QObject *, ObjectOwnership)
	Sets the ownership of object.

static ObjectOwnership	objectOwnership (QObject *)
	Returns the ownership of object.

Static Public Member Functions inherited from QObject
static QMetaObject::Connection	connect (const QObject sender, const char signal, const QObject receiver, const char member, Qt::ConnectionType=Qt::AutoConnection)
	\threadsafe

static QMetaObject::Connection	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)

static bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char member)
	\threadsafe

static bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &member)

static bool	disconnect (const QMetaObject::Connection &)
	Disconnect a connection.

template<typename Func1 , typename Func2 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object receiver, Func2 slot)

template<typename Func1 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject receiver, void **zero)

Protected Member Functions inherited from QQmlEngine
	QQmlEngine (QQmlEnginePrivate &dd, QObject *p)

bool	event (QEvent *) override
	\reimp

Protected Member Functions inherited from QJSEngine
	QJSEngine (QJSEnginePrivate &dd, QObject *parent=nullptr)

Protected Member Functions inherited from QObject
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.

int	senderSignalIndex () const

int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal.

bool	isSignalConnected (const QMetaMethod &signal) const

virtual void	timerEvent (QTimerEvent *event)
	This event handler can be reimplemented in a subclass to receive timer events for the object.

virtual void	childEvent (QChildEvent *event)
	This event handler can be reimplemented in a subclass to receive child events.

virtual void	customEvent (QEvent *event)
	This event handler can be reimplemented in a subclass to receive custom events.

virtual void	connectNotify (const QMetaMethod &signal)

virtual void	disconnectNotify (const QMetaMethod &signal)

	QObject (QObjectPrivate &dd, QObject *parent=nullptr)

Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Properties inherited from QQmlEngine
QString	offlineStoragePath
	the directory for storing offline user data

Properties inherited from QJSEngine
QString	uiLanguage
	the language to be used for translating user interface strings

Properties inherited from QObject
QString	objectName
	the name of this object

Related Symbols inherited from QQmlEngine
void	qmlRegisterModuleImport (const char uri, int moduleMajor, const char import, int importMajor, int importMinor)
	Registers a qmldir-import for module uri of major version moduleMajor.

void	qmlUnregisterModuleImport (const char uri, int moduleMajor, const char import, int importMajor, int importMinor)
	Removes a module import previously registered with qmlRegisterModuleImport()

QQmlEngine *	qmlEngine (const QObject *object)
	Returns the QQmlEngine associated with object, if any.

QQmlContext *	qmlContext (const QObject *object)
	Returns the QQmlContext associated with object, if any.

Related Symbols inherited from QJSEngine
QJSEngine *	qjsEngine (const QObject *object)

Related Symbols inherited from QObject
template< class T > T	qobject_cast (const QObject *object)
	Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.

template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()

template< typename T > QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()

	QObjectList
	\macro Q_CLASSINFO(Name, Value)

Detailed Description

QQmlApplicationEngine provides a convenient way to load an application from a single QML file.

Since: 5.1 \inmodule QtQml

This class combines a QQmlEngine and QQmlComponent to provide a convenient way to load a single QML file. It also exposes some central application functionality to QML, which a C++/QML hybrid application would normally control from C++.

It can be used like so:

#include <QGuiApplication>
#include <QQmlApplicationEngine>
 
int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);
    QQmlApplicationEngine engine("main.qml");
    return app.exec();
}

Unlike QQuickView, QQmlApplicationEngine does not automatically create a root window. If you are using visual items from Qt Quick, you will need to place them inside of a \l [QML] {Window}.

You can also use QCoreApplication with QQmlApplicationEngine, if you are not using any QML modules which require a QGuiApplication (such as QtQuick).

List of configuration changes from a default QQmlEngine:

\list

Connecting Qt.quit() to QCoreApplication::quit()
Automatically loads translation files from an i18n directory adjacent to the main QML file. \list
Translation files must have "qml_" prefix e.g. qml_ja_JP.qm. \endlist
Translations are reloaded when the QJSEngine::uiLanguage / Qt.uiLanguage property is changed.
Automatically sets an incubation controller if the scene contains a QQuickWindow.
Automatically sets a QQmlFileSelector as the url interceptor, applying file selectors to all QML files and assets. \endlist

The engine behavior can be further tweaked by using the inherited methods from QQmlEngine.

Definition at line 16 of file qqmlapplicationengine.h.

Constructor & Destructor Documentation

◆ QQmlApplicationEngine() [1/4]

QQmlApplicationEngine::QQmlApplicationEngine ( QObject * parent = nullptr )

Create a new QQmlApplicationEngine with the given parent.

You will have to call load() later in order to load a QML file.

Definition at line 278 of file qqmlapplicationengine.cpp.

References QJSEnginePrivate::addToDebugServer().

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◆ QQmlApplicationEngine() [2/4]

QQmlApplicationEngine::QQmlApplicationEngine	(	const QUrl &	url,
		QObject *	parent = nullptr )

Create a new QQmlApplicationEngine and loads the QML file at the given url.

This is provided as a convenience, and is the same as using the empty constructor and calling load afterwards.

Definition at line 288 of file qqmlapplicationengine.cpp.

References load(), and url.

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◆ QQmlApplicationEngine() [3/4]

QQmlApplicationEngine::QQmlApplicationEngine	(	QAnyStringView	uri,
		QAnyStringView	typeName,
		QObject *	parent = nullptr )

explicit

Create a new QQmlApplicationEngine and loads the QML type specified by uri and typeName This is provided as a convenience, and is the same as using the empty constructor and calling loadFromModule afterwards.

Since: 6.5

Definition at line 302 of file qqmlapplicationengine.cpp.

References loadFromModule(), and typeName.

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◆ QQmlApplicationEngine() [4/4]

QQmlApplicationEngine::QQmlApplicationEngine	(	const QString &	filePath,
		QObject *	parent = nullptr )

Create a new QQmlApplicationEngine and loads the QML file at the given filePath, which must be a local file path.

If a relative path is given then it will be interpreted as relative to the working directory of the application.

This is provided as a convenience, and is the same as using the empty constructor and calling load afterwards.

Definition at line 316 of file qqmlapplicationengine.cpp.

◆ ~QQmlApplicationEngine()

QQmlApplicationEngine::~QQmlApplicationEngine ( )

override

Destroys the QQmlApplicationEngine and all QML objects it loaded.

Definition at line 324 of file qqmlapplicationengine.cpp.

References d, and QJSEnginePrivate::removeFromDebugServer().

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Member Function Documentation

◆ load [1/2]

void QQmlApplicationEngine::load ( const QString & filePath )

slot

Loads the root QML file located at filePath.

filePath must be a path to a local file. If filePath is a relative path, it is taken as relative to the application's working directory. The object tree defined by the file is instantiated immediately.

If an error occurs, error messages are printed with qWarning.

Definition at line 355 of file qqmlapplicationengine.cpp.

References QUrl::AssumeLocalFile, d, and QUrl::fromUserInput().

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◆ load [2/2]

void QQmlApplicationEngine::load ( const QUrl & url )

slot

Loads the root QML file located at url.

The object tree defined by the file is created immediately for local file urls. Remote urls are loaded asynchronously, listen to the \l {QQmlApplicationEngine::objectCreated()}{objectCreated} signal to determine when the object tree is ready.

If an error occurs, the \l {QQmlApplicationEngine::objectCreated()}{objectCreated} signal is emitted with a null pointer as parameter and error messages are printed with qWarning.

Definition at line 341 of file qqmlapplicationengine.cpp.

References d, and url.

Referenced by QQmlApplicationEngine().

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◆ loadData

void QQmlApplicationEngine::loadData	(	const QByteArray &	data,
		const QUrl &	url = QUrl() )

slot

Loads the QML given in data.

The object tree defined by data is instantiated immediately.

If a url is specified it is used as the base url of the component. This affects relative paths within the data and error messages.

If an error occurs, error messages are printed with qWarning.

Definition at line 447 of file qqmlapplicationengine.cpp.

References d, and url.

◆ loadFromModule

void QQmlApplicationEngine::loadFromModule	(	QAnyStringView	uri,
		QAnyStringView	typeName )

slot

Loads the QML type typeName from the module specified by uri.

If the type originates from a QML file located at a remote url, the type will be loaded asynchronously. Listen to the \l {QQmlApplicationEngine::objectCreated()}{objectCreated} signal to determine when the object tree is ready.

If an error occurs, the \l {QQmlApplicationEngine::objectCreated()}{objectCreated} signal is emitted with a null pointer as parameter and error messages are printed with qWarning.

QQmlApplicationEngine engine;

engine.loadFromModule("QtQuick", "Rectangle");

Note: The module identified by uri is searched in the \l {QML Import Path}{import path}, in the same way as if you were doing {import uri} inside a QML file. If the module cannot be located there, this function will fail.

Since: 6.5

See also: QQmlComponent::loadFromModule

Definition at line 385 of file qqmlapplicationengine.cpp.

References d, and typeName.

Referenced by QQmlApplicationEngine().

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◆ objectCreated

QQmlApplicationEngine::objectCreated	(	QObject *	object,
		const QUrl &	url )

signal

This signal is emitted when an object finishes loading.

If loading was successful, object contains a pointer to the loaded object, otherwise the pointer is NULL.

The url to the component the object came from is also provided.

Note: If the path to the component was provided as a QString containing a relative path, the url will contain a fully resolved path to the file.

◆ objectCreationFailed

QQmlApplicationEngine::objectCreationFailed ( const QUrl & url )

signal

Since: 6.4

This signal is emitted when loading finishes because an error occurred.

The url to the component that failed to load is provided as an argument.

QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
 
// exit on error
QObject::connect(&engine, &QQmlApplicationEngine::objectCreationFailed,
    &app, []() { QCoreApplication::exit(-1); }, Qt::QueuedConnection);
engine.load(QUrl());
return app.exec();

Note: If the path to the component was provided as a QString containing a relative path, the url will contain a fully resolved path to the file.

See also \l {QQmlApplicationEngine::objectCreated}, which will be emitted in addition to this signal (even though creation failed).

◆ rootObjects()

QList< QObject * > QQmlApplicationEngine::rootObjects ( ) const

Returns a list of all the root objects instantiated by the QQmlApplicationEngine.

This will only contain objects loaded via load() or a convenience constructor.

Note: In Qt versions prior to 5.9, this function is marked as non-{const}.

Definition at line 461 of file qqmlapplicationengine.cpp.

References d.

◆ setExtraFileSelectors

void QQmlApplicationEngine::setExtraFileSelectors ( const QStringList & extraFileSelectors )

slot

Sets the extraFileSelectors to be passed to the internal QQmlFileSelector used for resolving URLs to local files.

The extraFileSelectors are applied when the first QML file is loaded. Setting them afterwards has no effect.

See also: QQmlFileSelector; QFileSelector::setExtraSelectors

Since: 6.0

Definition at line 427 of file qqmlapplicationengine.cpp.

References d, and qWarning.

◆ setInitialProperties

void QQmlApplicationEngine::setInitialProperties ( const QVariantMap & initialProperties )

slot

Sets the initialProperties with which the QML component gets initialized after it gets loaded.

QQmlApplicationEngine engine;
 
EventDatabase eventDatabase;
EventMonitor eventMonitor;
 
engine.setInitialProperties({
    { "eventDatabase", QVariant::fromValue(&eventDatabase) },
    { "eventMonitor", QVariant::fromValue(&eventMonitor) }
});

See also: QQmlComponent::setInitialProperties; QQmlApplicationEngine::load; QQmlApplicationEngine::loadData

Since: 5.14

Definition at line 412 of file qqmlapplicationengine.cpp.

References d.

The documentation for this class was generated from the following files:

qtdeclarative/src/qml/qml/qqmlapplicationengine.h (281497bfbc6af36c2051d255eed350c03da74439)
qtdeclarative/src/qml/qml/qqmlapplicationengine.cpp (8bdbe3d50f26d18d81acdb74703c73c419ad922b)

Public Slots

Signals

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QQmlApplicationEngine() [1/4]

◆ QQmlApplicationEngine() [2/4]

◆ QQmlApplicationEngine() [3/4]

◆ QQmlApplicationEngine() [4/4]

◆ ~QQmlApplicationEngine()

Member Function Documentation

◆ load [1/2]

◆ load [2/2]

◆ loadData

◆ loadFromModule

◆ objectCreated

◆ objectCreationFailed

◆ rootObjects()

◆ setExtraFileSelectors

◆ setInitialProperties