Struct qt_qml::QQmlEngine

#[repr(C)]pub struct QQmlEngine { /* fields omitted */ }

Each QML component is instantiated in a QQmlContext. QQmlContext's are essential for passing data to QML components. In QML, contexts are arranged hierarchically and this hierarchy is managed by the QQmlEngine.

C++ class: QQmlEngine.

C++ documentation:

Each QML component is instantiated in a QQmlContext. QQmlContext's are essential for passing data to QML components. In QML, contexts are arranged hierarchically and this hierarchy is managed by the QQmlEngine.

Prior to creating any QML components, an application must have created a QQmlEngine to gain access to a QML context. The following example shows how to create a simple Text item.

QQmlEngine engine;
QQmlComponent component(&engine);
component.setData("import QtQuick 2.0\nText { text: "Hello world!" }", QUrl());
QQuickItem item = qobject_cast<QQuickItem >(component.create());
//add item to view, etc
...

In this case, the Text item will be created in the engine's root context.

Methods

impl QQmlEngine

pub fn slot_retranslate(&self) -> Receiver<()>

Refreshes all binding expressions that use strings marked for translation.

Returns a built-in Qt slot QQmlEngine::retranslate that can be passed to qt_core::Signal::connect.

C++ documentation:

Refreshes all binding expressions that use strings marked for translation.

Call this function after you have installed a new translator with QCoreApplication::installTranslator, to ensure that your user-interface shows up-to-date translations.

Note: Due to a limitation in the implementation, this function refreshes all the engine's bindings, not only those that use strings marked for translation. This may be optimized in a future release.

This function was introduced in Qt 5.10.

pub fn quit(&self) -> Signal<()>

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

Returns a built-in Qt signal QQmlEngine::quit that can be passed to qt_core::Signal::connect.

C++ documentation:

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

See also exit().

pub fn exit(&self) -> Signal<(c_int,)>

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.

Returns a built-in Qt signal QQmlEngine::exit that can be passed to qt_core::Signal::connect.

C++ documentation:

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.

This function was introduced in Qt 5.8.

See also quit().

pub fn warnings(&self) -> Signal<(*const QListOfQQmlError,)>

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

Returns a built-in Qt signal QQmlEngine::warnings that can be passed to qt_core::Signal::connect.

C++ documentation:

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

pub unsafe fn add_image_provider(
    &self,
    id: impl CastInto<Ref<QString>>,
    arg2: impl CastInto<Ptr<QQmlImageProviderBase>>
)

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

Calls C++ function: void QQmlEngine::addImageProvider(const QString& id, QQmlImageProviderBase* arg2).

C++ documentation:

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

Image providers enable support for pixmap and threaded image requests. See the QQuickImageProvider 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(), QQuickImageProvider, and QQmlImageProviderBase.

pub unsafe fn add_import_path(&self, dir: impl CastInto<Ref<QString>>)

Adds path as a directory where the engine searches for installed modules in a URL-based directory structure.

Calls C++ function: void QQmlEngine::addImportPath(const QString& dir).

C++ documentation:

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, a Qt Resource path (:/imports), a Qt Resource url (qrc:/imports) or a URL.

The path will be converted into canonical form before it is added to the import path list.

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

See also setImportPathList() and QML Modules.

pub unsafe fn add_named_bundle(
    &self,
    name: impl CastInto<Ref<QString>>,
    file_name: impl CastInto<Ref<QString>>
) -> bool

Calls C++ function: bool QQmlEngine::addNamedBundle(const QString& name, const QString& fileName).

pub unsafe fn add_plugin_path(&self, dir: impl CastInto<Ref<QString>>)

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

Calls C++ function: void QQmlEngine::addPluginPath(const QString& dir).

C++ documentation:

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().

pub unsafe fn base_url(&self) -> CppBox<QUrl>

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

Calls C++ function: QUrl QQmlEngine::baseUrl() const.

C++ documentation:

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

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

See also setBaseUrl().

pub unsafe fn clear_component_cache(&self)

Clears the engine's internal component cache.

Calls C++ function: void QQmlEngine::clearComponentCache().

C++ documentation:

Clears the engine's internal component cache.

This function causes the property metadata of all components previously loaded by the engine to be destroyed. All previously loaded components and the property bindings for all extant objects created from those components will cease to function.

This function returns the engine to a state where it does not contain any loaded component data. This may be useful in order to reload a smaller subset of the previous component set, or to load a new version of a previously loaded component.

Once the component cache has been cleared, components must be loaded before any new objects can be created.

See also trimComponentCache().

pub unsafe fn context_for_object(
    arg1: impl CastInto<Ptr<QObject>>
) -> QPtr<QQmlContext>

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

Calls C++ function: static QQmlContext* QQmlEngine::contextForObject(const QObject* arg1).

C++ documentation:

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

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

See also setContextForObject(), qmlContext(), and qmlEngine().

pub unsafe fn image_provider(
    &self,
    id: impl CastInto<Ref<QString>>
) -> Ptr<QQmlImageProviderBase>

Returns the image provider set for providerId if found; otherwise returns nullptr.

Calls C++ function: QQmlImageProviderBase* QQmlEngine::imageProvider(const QString& id) const.

C++ documentation:

Returns the image provider set for providerId if found; otherwise returns nullptr.

See also QQuickImageProvider.

pub unsafe fn import_path_list(&self) -> CppBox<QStringList>

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

Calls C++ function: QStringList QQmlEngine::importPathList() const.

C++ documentation:

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 QQmlEngine 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 QML extensions plugins.

By default, the list contains the directory of the application executable, paths specified in the QML2_IMPORT_PATH environment variable, and the builtin Qml2ImportsPath from QLibraryInfo.

See also addImportPath() and setImportPathList().

pub unsafe fn import_plugin(
    &self,
    file_path: impl CastInto<Ref<QString>>,
    uri: impl CastInto<Ref<QString>>,
    errors: impl CastInto<Ptr<QListOfQQmlError>>
) -> bool

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

Calls C++ function: bool QQmlEngine::importPlugin(const QString& filePath, const QString& uri, QList<QQmlError>* errors).

C++ documentation:

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, the errors list will have any errors which occurred prepended to it.

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

pub unsafe fn incubation_controller(&self) -> Ptr<QQmlIncubationController>

Returns the currently set incubation controller, or 0 if no controller has been set.

Calls C++ function: QQmlIncubationController* QQmlEngine::incubationController() const.

C++ documentation:

Returns the currently set incubation controller, or 0 if no controller has been set.

See also setIncubationController().

pub unsafe fn meta_object(&self) -> Ptr<QMetaObject>

Calls C++ function: virtual const QMetaObject* QQmlEngine::metaObject() const.

pub unsafe fn network_access_manager_factory(
    &self
) -> Ptr<QQmlNetworkAccessManagerFactory>

Returns the current QQmlNetworkAccessManagerFactory.

Calls C++ function: QQmlNetworkAccessManagerFactory* QQmlEngine::networkAccessManagerFactory() const.

C++ documentation:

Returns the current QQmlNetworkAccessManagerFactory.

See also setNetworkAccessManagerFactory().

pub unsafe fn new_1a(p: impl CastInto<Ptr<QObject>>) -> QBox<QQmlEngine>

Create a new QQmlEngine with the given parent.

Calls C++ function: [constructor] void QQmlEngine::QQmlEngine(QObject* p = …).

C++ documentation:

Create a new QQmlEngine with the given parent.

pub unsafe fn new_0a() -> QBox<QQmlEngine>

Each QML component is instantiated in a QQmlContext. QQmlContext's are essential for passing data to QML components. In QML, contexts are arranged hierarchically and this hierarchy is managed by the QQmlEngine.

Calls C++ function: [constructor] void QQmlEngine::QQmlEngine().

C++ documentation:

Each QML component is instantiated in a QQmlContext. QQmlContext's are essential for passing data to QML components. In QML, contexts are arranged hierarchically and this hierarchy is managed by the QQmlEngine.

Prior to creating any QML components, an application must have created a QQmlEngine to gain access to a QML context. The following example shows how to create a simple Text item.

QQmlEngine engine;
QQmlComponent component(&engine);
component.setData("import QtQuick 2.0\nText { text: "Hello world!" }", QUrl());
QQuickItem item = qobject_cast<QQuickItem >(component.create());
//add item to view, etc
...

In this case, the Text item will be created in the engine's root context.

pub unsafe fn object_ownership(
    arg1: impl CastInto<Ptr<QObject>>
) -> ObjectOwnership

Returns the ownership of object.

Calls C++ function: static QQmlEngine::ObjectOwnership QQmlEngine::objectOwnership(QObject* arg1).

C++ documentation:

Returns the ownership of object.

See also setObjectOwnership().

pub unsafe fn offline_storage_database_file_path(
    &self,
    database_name: impl CastInto<Ref<QString>>
) -> CppBox<QString>

Returns the file path where a Local Storage database with the identifier databaseName is (or would be) located.

Calls C++ function: QString QQmlEngine::offlineStorageDatabaseFilePath(const QString& databaseName) const.

C++ documentation:

Returns the file path where a Local Storage database with the identifier databaseName is (or would be) located.

This function was introduced in Qt 5.9.

See also LocalStorage.openDatabaseSync().

pub unsafe fn offline_storage_path(&self) -> CppBox<QString>

This property holds the directory for storing offline user data

Calls C++ function: QString QQmlEngine::offlineStoragePath() const.

C++ documentation:

This property holds the directory for storing offline user data

Returns the directory where SQL and other offline storage is placed.

The SQL databases created with openDatabase() are stored here.

The default is QML/OfflineStorage in the platform-standard user application data directory.

Note that the path may not currently exist on the filesystem, so callers wanting to create new files at this location should create it first - see QDir::mkpath().

Access functions:

QString	offlineStoragePath() const
void	setOfflineStoragePath(const QString &dir)

pub unsafe fn output_warnings_to_standard_error(&self) -> bool

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

Calls C++ function: bool QQmlEngine::outputWarningsToStandardError() const.

C++ documentation:

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().

pub unsafe fn plugin_path_list(&self) -> CppBox<QStringList>

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

Calls C++ function: QStringList QQmlEngine::pluginPathList() const.

C++ documentation:

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().

pub unsafe fn qt_metacall(
    &self,
    arg1: Call,
    arg2: c_int,
    arg3: *mut *mut c_void
) -> c_int

Calls C++ function: virtual int QQmlEngine::qt_metacall(QMetaObject::Call arg1, int arg2, void** arg3).

pub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void

Calls C++ function: virtual void* QQmlEngine::qt_metacast(const char* arg1).

pub unsafe fn remove_image_provider(&self, id: impl CastInto<Ref<QString>>)

Removes the image provider for providerId.

Calls C++ function: void QQmlEngine::removeImageProvider(const QString& id).

C++ documentation:

Removes the image provider for providerId.

See also addImageProvider() and QQuickImageProvider.

pub unsafe fn retranslate(&self)

This is supported on cpp_lib_version="5.13.0" or cpp_lib_version="5.11.3" or cpp_lib_version="5.12.2" or cpp_lib_version="5.14.0" only.

Refreshes all binding expressions that use strings marked for translation.

Calls C++ function: [slot] void QQmlEngine::retranslate().

C++ documentation:

Refreshes all binding expressions that use strings marked for translation.

Call this function after you have installed a new translator with QCoreApplication::installTranslator, to ensure that your user-interface shows up-to-date translations.

Note: Due to a limitation in the implementation, this function refreshes all the engine's bindings, not only those that use strings marked for translation. This may be optimized in a future release.

This function was introduced in Qt 5.10.

pub unsafe fn root_context(&self) -> QPtr<QQmlContext>

Returns the engine's root context.

Calls C++ function: QQmlContext* QQmlEngine::rootContext() const.

C++ documentation:

Returns the engine's root context.

The root context is automatically created by the QQmlEngine. 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.

pub unsafe fn set_base_url(&self, arg1: impl CastInto<Ref<QUrl>>)

Set the base URL for this engine to url.

Calls C++ function: void QQmlEngine::setBaseUrl(const QUrl& arg1).

C++ documentation:

Set the base URL for this engine to url.

See also baseUrl().

pub unsafe fn set_context_for_object(
    arg1: impl CastInto<Ptr<QObject>>,
    arg2: impl CastInto<Ptr<QQmlContext>>
)

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

Calls C++ function: static void QQmlEngine::setContextForObject(QObject* arg1, QQmlContext* arg2).

C++ documentation:

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

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

See also contextForObject().

pub unsafe fn set_import_path_list(
    &self,
    paths: impl CastInto<Ref<QStringList>>
)

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

Calls C++ function: void QQmlEngine::setImportPathList(const QStringList& paths).

C++ documentation:

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 QML2_IMPORT_PATH environment variable, and the builtin Qml2ImportsPath from QLibraryInfo.

See also importPathList() and addImportPath().

pub unsafe fn set_incubation_controller(
    &self,
    arg1: impl CastInto<Ptr<QQmlIncubationController>>
)

Sets the engine's incubation controller. The engine can only have one active controller and it does not take ownership of it.

Calls C++ function: void QQmlEngine::setIncubationController(QQmlIncubationController* arg1).

C++ documentation:

Sets the engine's incubation controller. The engine can only have one active controller and it does not take ownership of it.

See also incubationController().

pub unsafe fn set_network_access_manager_factory(
    &self,
    arg1: impl CastInto<Ptr<QQmlNetworkAccessManagerFactory>>
)

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

Calls C++ function: void QQmlEngine::setNetworkAccessManagerFactory(QQmlNetworkAccessManagerFactory* arg1).

C++ documentation:

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.

Note: QQmlEngine does not take ownership of the factory.

See also networkAccessManagerFactory().

pub unsafe fn set_object_ownership(
    arg1: impl CastInto<Ptr<QObject>>,
    arg2: ObjectOwnership
)

Sets the ownership of object.

Calls C++ function: static void QQmlEngine::setObjectOwnership(QObject* arg1, QQmlEngine::ObjectOwnership arg2).

C++ documentation:

Sets the ownership of object.

See also objectOwnership().

pub unsafe fn set_offline_storage_path(&self, dir: impl CastInto<Ref<QString>>)

This property holds the directory for storing offline user data

Calls C++ function: void QQmlEngine::setOfflineStoragePath(const QString& dir).

C++ documentation:

This property holds the directory for storing offline user data

Returns the directory where SQL and other offline storage is placed.

The SQL databases created with openDatabase() are stored here.

The default is QML/OfflineStorage in the platform-standard user application data directory.

Note that the path may not currently exist on the filesystem, so callers wanting to create new files at this location should create it first - see QDir::mkpath().

Access functions:

QString	offlineStoragePath() const
void	setOfflineStoragePath(const QString &dir)

pub unsafe fn set_output_warnings_to_standard_error(&self, arg1: bool)

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

Calls C++ function: void QQmlEngine::setOutputWarningsToStandardError(bool arg1).

C++ documentation:

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, only the warnings() signal will be emitted. This allows applications to handle warning output themselves.

The default value is true.

See also outputWarningsToStandardError().

pub unsafe fn set_plugin_path_list(
    &self,
    paths: impl CastInto<Ref<QStringList>>
)

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

Calls C++ function: void QQmlEngine::setPluginPathList(const QStringList& paths).

C++ documentation:

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().

pub unsafe fn set_url_interceptor(
    &self,
    url_interceptor: impl CastInto<Ptr<QQmlAbstractUrlInterceptor>>
)

Calls C++ function: void QQmlEngine::setUrlInterceptor(QQmlAbstractUrlInterceptor* urlInterceptor).

pub unsafe fn static_meta_object() -> Ref<QMetaObject>

Returns a reference to the staticMetaObject field.

pub unsafe fn tr(
    s: *const c_char,
    c: *const c_char,
    n: c_int
) -> CppBox<QString>

Calls C++ function: static QString QQmlEngine::tr(const char* s, const char* c, int n).

pub unsafe fn tr_utf8(
    s: *const c_char,
    c: *const c_char,
    n: c_int
) -> CppBox<QString>

Calls C++ function: static QString QQmlEngine::trUtf8(const char* s, const char* c, int n).

pub unsafe fn trim_component_cache(&self)

Trims the engine's internal component cache.

Calls C++ function: void QQmlEngine::trimComponentCache().

C++ documentation:

Trims the engine's internal component cache.

This function causes the property metadata of any loaded components which are not currently in use to be destroyed.

A component is considered to be in use if there are any extant instances of the component itself, any instances of other components that use the component, or any objects instantiated by any of those components.

See also clearComponentCache().

pub unsafe fn url_interceptor(&self) -> Ptr<QQmlAbstractUrlInterceptor>

Calls C++ function: QQmlAbstractUrlInterceptor* QQmlEngine::urlInterceptor() const.

Methods from Deref<Target = QJSEngine>

pub unsafe fn collect_garbage(&self)

Runs the garbage collector.

Calls C++ function: void QJSEngine::collectGarbage().

C++ documentation:

Runs the garbage collector.

The garbage collector will attempt to reclaim memory by locating and disposing of objects that are no longer reachable in the script environment.

Normally you don't need to call this function; the garbage collector will automatically be invoked when the QJSEngine decides that it's wise to do so (i.e. when a certain number of new objects have been created). However, you can call this function to explicitly request that garbage collection should be performed as soon as possible.

pub unsafe fn evaluate_3a(
    &self,
    program: impl CastInto<Ref<QString>>,
    file_name: impl CastInto<Ref<QString>>,
    line_number: c_int
) -> CppBox<QJSValue>

Evaluates program, using lineNumber as the base line number, and returns the result of the evaluation.

Calls C++ function: QJSValue QJSEngine::evaluate(const QString& program, const QString& fileName = …, int lineNumber = …).

C++ documentation:

Evaluates program, using lineNumber as the base line number, and returns the result of the evaluation.

The script code will be evaluated in the context of the global object.

The evaluation of program can cause an exception in the engine; in this case the return value will be the exception that was thrown (typically an Error object; see QJSValue::isError()).

lineNumber is used to specify a starting line number for program; line number information reported by the engine that pertains to this evaluation will be based on this argument. For example, if program consists of two lines of code, and the statement on the second line causes a script exception, the exception line number would be lineNumber plus one. When no starting line number is specified, line numbers will be 1-based.

fileName is used for error reporting. For example, in error objects the file name is accessible through the "fileName" property if it is provided with this function.

Note: If an exception was thrown and the exception value is not an Error instance (i.e., QJSValue::isError() returns false), the exception value will still be returned, but there is currently no API for detecting that an exception did occur in this case.

pub unsafe fn evaluate_2a(
    &self,
    program: impl CastInto<Ref<QString>>,
    file_name: impl CastInto<Ref<QString>>
) -> CppBox<QJSValue>

Evaluates program, using lineNumber as the base line number, and returns the result of the evaluation.

Calls C++ function: QJSValue QJSEngine::evaluate(const QString& program, const QString& fileName = …).

C++ documentation:

Evaluates program, using lineNumber as the base line number, and returns the result of the evaluation.

The script code will be evaluated in the context of the global object.

The evaluation of program can cause an exception in the engine; in this case the return value will be the exception that was thrown (typically an Error object; see QJSValue::isError()).

lineNumber is used to specify a starting line number for program; line number information reported by the engine that pertains to this evaluation will be based on this argument. For example, if program consists of two lines of code, and the statement on the second line causes a script exception, the exception line number would be lineNumber plus one. When no starting line number is specified, line numbers will be 1-based.

fileName is used for error reporting. For example, in error objects the file name is accessible through the "fileName" property if it is provided with this function.

Note: If an exception was thrown and the exception value is not an Error instance (i.e., QJSValue::isError() returns false), the exception value will still be returned, but there is currently no API for detecting that an exception did occur in this case.

pub unsafe fn evaluate_1a(
    &self,
    program: impl CastInto<Ref<QString>>
) -> CppBox<QJSValue>

Evaluates program, using lineNumber as the base line number, and returns the result of the evaluation.

Calls C++ function: QJSValue QJSEngine::evaluate(const QString& program).

C++ documentation:

Evaluates program, using lineNumber as the base line number, and returns the result of the evaluation.

The script code will be evaluated in the context of the global object.

The evaluation of program can cause an exception in the engine; in this case the return value will be the exception that was thrown (typically an Error object; see QJSValue::isError()).

lineNumber is used to specify a starting line number for program; line number information reported by the engine that pertains to this evaluation will be based on this argument. For example, if program consists of two lines of code, and the statement on the second line causes a script exception, the exception line number would be lineNumber plus one. When no starting line number is specified, line numbers will be 1-based.

fileName is used for error reporting. For example, in error objects the file name is accessible through the "fileName" property if it is provided with this function.

Note: If an exception was thrown and the exception value is not an Error instance (i.e., QJSValue::isError() returns false), the exception value will still be returned, but there is currently no API for detecting that an exception did occur in this case.

pub unsafe fn global_object(&self) -> CppBox<QJSValue>

Returns this engine's Global Object.

Calls C++ function: QJSValue QJSEngine::globalObject() const.

C++ documentation:

Returns this engine's Global Object.

By default, the Global Object contains the built-in objects that are part of ECMA-262, such as Math, Date and String. Additionally, you can set properties of the Global Object to make your own extensions available to all script code. Non-local variables in script code will be created as properties of the Global Object, as well as local variables in global code.

pub unsafe fn import_module(
    &self,
    file_name: impl CastInto<Ref<QString>>
) -> CppBox<QJSValue>

This is supported on cpp_lib_version="5.13.0" or cpp_lib_version="5.12.2" or cpp_lib_version="5.14.0" only.

Imports the module located at fileName and returns a module namespace object that contains all exported variables, constants and functions as properties.

Calls C++ function: QJSValue QJSEngine::importModule(const QString& fileName).

C++ documentation:

Imports the module located at fileName and returns a module namespace object that contains all exported variables, constants and functions as properties.

If this is the first time the module is imported in the engine, the file is loaded from the specified location in either the local file system or the Qt resource system and evaluated as an ECMAScript module. The file is expected to be encoded in UTF-8 text.

Subsequent imports of the same module will return the previously imported instance. Modules are singletons and remain around until the engine is destroyed.

The specified fileName will internally be normalized using QFileInfo::canonicalFilePath(). That means that multiple imports of the same file on disk using different relative paths will load the file only once.

Note: If an exception is thrown during the loading of the module, the return value will be the exception (typically an Error object; see QJSValue::isError()).

This function was introduced in Qt 5.12.

pub unsafe fn install_extensions_2a(
    &self,
    extensions: QFlags<Extension>,
    object: impl CastInto<Ref<QJSValue>>
)

Installs JavaScript extensions to add functionality that is not available in a standard ECMAScript implementation.

Calls C++ function: void QJSEngine::installExtensions(QFlags<QJSEngine::Extension> extensions, const QJSValue& object = …).

C++ documentation:

Installs JavaScript extensions to add functionality that is not available in a standard ECMAScript implementation.

The extensions are installed on the given object, or on the Global Object if no object is specified.

Several extensions can be installed at once by OR-ing the enum values:

installExtensions(QJSEngine::TranslationExtension | QJSEngine::ConsoleExtension);

This function was introduced in Qt 5.6.

See also Extension.

pub unsafe fn install_extensions_1a(&self, extensions: QFlags<Extension>)

Installs JavaScript extensions to add functionality that is not available in a standard ECMAScript implementation.

Calls C++ function: void QJSEngine::installExtensions(QFlags<QJSEngine::Extension> extensions).

C++ documentation:

Installs JavaScript extensions to add functionality that is not available in a standard ECMAScript implementation.

The extensions are installed on the given object, or on the Global Object if no object is specified.

Several extensions can be installed at once by OR-ing the enum values:

installExtensions(QJSEngine::TranslationExtension | QJSEngine::ConsoleExtension);

This function was introduced in Qt 5.6.

See also Extension.

pub unsafe fn install_translator_functions_1a(
    &self,
    object: impl CastInto<Ref<QJSValue>>
)

This function is obsolete. It is provided to keep old source code working. We strongly advise against using it in new code.

Calls C++ function: void QJSEngine::installTranslatorFunctions(const QJSValue& object = …).

C++ documentation:

This function is obsolete. It is provided to keep old source code working. We strongly advise against using it in new code.

Installs translator functions on the given object, or on the Global Object if no object is specified.

The relation between script translator functions and C++ translator functions is described in the following table:

Script Function	Corresponding C++ Function
qsTr()	QObject::tr()
QT_TR_NOOP()	QT_TR_NOOP()
qsTranslate()	QCoreApplication::translate()
QT_TRANSLATE_NOOP()	QT_TRANSLATE_NOOP()
qsTrId()	qtTrId()
QT_TRID_NOOP()	QT_TRID_NOOP()

It also adds an arg() method to the string prototype.

This function was introduced in Qt 5.4.

See also Internationalization with Qt.

pub unsafe fn install_translator_functions_0a(&self)

This function is obsolete. It is provided to keep old source code working. We strongly advise against using it in new code.

Calls C++ function: void QJSEngine::installTranslatorFunctions().

C++ documentation:

This function is obsolete. It is provided to keep old source code working. We strongly advise against using it in new code.

Installs translator functions on the given object, or on the Global Object if no object is specified.

The relation between script translator functions and C++ translator functions is described in the following table:

Script Function	Corresponding C++ Function
qsTr()	QObject::tr()
QT_TR_NOOP()	QT_TR_NOOP()
qsTranslate()	QCoreApplication::translate()
QT_TRANSLATE_NOOP()	QT_TRANSLATE_NOOP()
qsTrId()	qtTrId()
QT_TRID_NOOP()	QT_TRID_NOOP()

It also adds an arg() method to the string prototype.

This function was introduced in Qt 5.4.

See also Internationalization with Qt.

pub unsafe fn is_interrupted(&self) -> bool

This is supported on cpp_lib_version="5.14.0" only.

Returns whether JavaScript execution is currently interrupted.

Calls C++ function: bool QJSEngine::isInterrupted() const.

C++ documentation:

Returns whether JavaScript execution is currently interrupted.

This function was introduced in Qt 5.14.

See also setInterrupted().

pub unsafe fn meta_object(&self) -> Ptr<QMetaObject>

Calls C++ function: virtual const QMetaObject* QJSEngine::metaObject() const.

pub unsafe fn new_array_1a(&self, length: c_uint) -> CppBox<QJSValue>

Creates a JavaScript object of class Array with the given length.

Calls C++ function: QJSValue QJSEngine::newArray(unsigned int length = …).

C++ documentation:

Creates a JavaScript object of class Array with the given length.

See also newObject().

pub unsafe fn new_array_0a(&self) -> CppBox<QJSValue>

Creates a JavaScript object of class Array with the given length.

Calls C++ function: QJSValue QJSEngine::newArray().

C++ documentation:

Creates a JavaScript object of class Array with the given length.

See also newObject().

pub unsafe fn new_error_object_2a(
    &self,
    error_type: ErrorType,
    message: impl CastInto<Ref<QString>>
) -> CppBox<QJSValue>

This is supported on cpp_lib_version="5.13.0" or cpp_lib_version="5.12.2" or cpp_lib_version="5.14.0" only.

Creates a JavaScript object of class Error.

Calls C++ function: QJSValue QJSEngine::newErrorObject(QJSValue::ErrorType errorType, const QString& message = …).

C++ documentation:

Creates a JavaScript object of class Error.

The prototype of the created object will be errorType.

This function was introduced in Qt 5.12.

See also newObject(), throwError(), and QJSValue::isError().

pub unsafe fn new_error_object_1a(
    &self,
    error_type: ErrorType
) -> CppBox<QJSValue>

This is supported on cpp_lib_version="5.13.0" or cpp_lib_version="5.12.2" or cpp_lib_version="5.14.0" only.

Creates a JavaScript object of class Error.

Calls C++ function: QJSValue QJSEngine::newErrorObject(QJSValue::ErrorType errorType).

C++ documentation:

Creates a JavaScript object of class Error.

The prototype of the created object will be errorType.

This function was introduced in Qt 5.12.

See also newObject(), throwError(), and QJSValue::isError().

pub unsafe fn new_object(&self) -> CppBox<QJSValue>

Creates a JavaScript object of class Object.

Calls C++ function: QJSValue QJSEngine::newObject().

C++ documentation:

Creates a JavaScript object of class Object.

The prototype of the created object will be the Object prototype object.

See also newArray() and QJSValue::setProperty().

pub unsafe fn new_q_meta_object(
    &self,
    meta_object: impl CastInto<Ptr<QMetaObject>>
) -> CppBox<QJSValue>

Creates a JavaScript object that wraps the given QMetaObject The metaObject must outlive the script engine. It is recommended to only use this method with static metaobjects.

Calls C++ function: QJSValue QJSEngine::newQMetaObject(const QMetaObject* metaObject).

C++ documentation:

Creates a JavaScript object that wraps the given QMetaObject The metaObject must outlive the script engine. It is recommended to only use this method with static metaobjects.

When called as a constructor, a new instance of the class will be created. Only constructors exposed by Q_INVOKABLE will be visible from the script engine.

This function was introduced in Qt 5.8.

See also newQObject() and QObject Integration.

pub unsafe fn new_q_object(
    &self,
    object: impl CastInto<Ptr<QObject>>
) -> CppBox<QJSValue>

Creates a JavaScript object that wraps the given QObject object, using JavaScriptOwnership.

Calls C++ function: QJSValue QJSEngine::newQObject(QObject* object).

C++ documentation:

Creates a JavaScript object that wraps the given QObject object, using JavaScriptOwnership.

Signals and slots, properties and children of object are available as properties of the created QJSValue.

If object is a null pointer, this function returns a null value.

If a default prototype has been registered for the object's class (or its superclass, recursively), the prototype of the new script object will be set to be that default prototype.

If the given object is deleted outside of the engine's control, any attempt to access the deleted QObject's members through the JavaScript wrapper object (either by script code or C++) will result in a script exception.

See also QJSValue::toQObject().

pub unsafe fn qt_metacall(
    &self,
    arg1: Call,
    arg2: c_int,
    arg3: *mut *mut c_void
) -> c_int

Calls C++ function: virtual int QJSEngine::qt_metacall(QMetaObject::Call arg1, int arg2, void** arg3).

pub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void

Calls C++ function: virtual void* QJSEngine::qt_metacast(const char* arg1).

pub unsafe fn set_interrupted(&self, interrupted: bool)

This is supported on cpp_lib_version="5.14.0" only.

Interrupts or re-enables JavaScript execution.

Calls C++ function: void QJSEngine::setInterrupted(bool interrupted).

C++ documentation:

Interrupts or re-enables JavaScript execution.

If interrupted is true, any JavaScript executed by this engine immediately aborts and returns an error object until this function is called again with a value of false for interrupted.

This function is thread safe. You may call it from a different thread in order to interrupt, for example, an infinite loop in JavaScript.

This function was introduced in Qt 5.14.

See also isInterrupted().

pub unsafe fn throw_error_q_string(&self, message: impl CastInto<Ref<QString>>)

This is supported on cpp_lib_version="5.13.0" or cpp_lib_version="5.12.2" or cpp_lib_version="5.14.0" only.

Throws a run-time error (exception) with the given message.

Calls C++ function: void QJSEngine::throwError(const QString& message).

C++ documentation:

Throws a run-time error (exception) with the given message.

This method is the C++ counterpart of a throw() expression in JavaScript. It enables C++ code to report run-time errors to QJSEngine. Therefore it should only be called from C++ code that was invoked by a JavaScript function through QJSEngine.

When returning from C++, the engine will interrupt the normal flow of execution and call the the next pre-registered exception handler with an error object that contains the given message. The error object will point to the location of the top-most context on the JavaScript caller stack; specifically, it will have properties lineNumber, fileName and stack. These properties are described in Script Exceptions.

In the following example a C++ method in FileAccess.cpp throws an error in qmlFile.qml at the position where readFileAsText() is called:

// qmlFile.qml
function someFunction() {
    ...
    var text = FileAccess.readFileAsText("/path/to/file.txt");
}

// FileAccess.cpp
// Assuming that FileAccess is a QObject-derived class that has been
// registered as a singleton type and provides an invokable method
// readFileAsText()
QJSValue FileAccess::readFileAsText(const QString & filePath) {
    QFile file(filePath);
    if (!file.open(QIODevice::ReadOnly)) {
      jsEngine->throwError(file.errorString());
      return QString();
    }
    ...
    return content;
}

It is also possible to catch the thrown error in JavaScript:

// qmlFile.qml
function someFunction() {
    ...
    var text;
    try {
      text = FileAccess.readFileAsText("/path/to/file.txt");
    } catch (error) {
      console.warn("In " + error.fileName + ":" + "error.lineNumber" +
                   ": " + error.message);
    }
}

If you need a more specific run-time error to describe an exception, you can use the throwError(QJSValue::ErrorType errorType, const QString &message) overload.

This function was introduced in Qt 5.12.

See also Script Exceptions.

pub unsafe fn throw_error_error_type_q_string(
    &self,
    error_type: ErrorType,
    message: impl CastInto<Ref<QString>>
)

This is supported on cpp_lib_version="5.13.0" or cpp_lib_version="5.12.2" or cpp_lib_version="5.14.0" only.

This function overloads throwError().

Calls C++ function: void QJSEngine::throwError(QJSValue::ErrorType errorType, const QString& message = …).

C++ documentation:

This function overloads throwError().

Throws a run-time error (exception) with the given errorType and message.

// Assuming that DataEntry is a QObject-derived class that has been
// registered as a singleton type and provides an invokable method
// setAge().
void DataEntry::setAge(int age) {
    if (age < 0 || age > 200) {
      jsEngine->throwError(QJSValue::RangeError,
                           "Age must be between 0 and 200");
    }
    ...
}

This function was introduced in Qt 5.12.

See also Script Exceptions and newErrorObject().

pub unsafe fn throw_error_error_type(&self, error_type: ErrorType)

This is supported on cpp_lib_version="5.13.0" or cpp_lib_version="5.12.2" or cpp_lib_version="5.14.0" only.

This function overloads throwError().

Calls C++ function: void QJSEngine::throwError(QJSValue::ErrorType errorType).

C++ documentation:

This function overloads throwError().

Throws a run-time error (exception) with the given errorType and message.

// Assuming that DataEntry is a QObject-derived class that has been
// registered as a singleton type and provides an invokable method
// setAge().
void DataEntry::setAge(int age) {
    if (age < 0 || age > 200) {
      jsEngine->throwError(QJSValue::RangeError,
                           "Age must be between 0 and 200");
    }
    ...
}

This function was introduced in Qt 5.12.

See also Script Exceptions and newErrorObject().

Trait Implementations

impl CppDeletable for QQmlEngine

unsafe fn delete(&self)

Destroys the QQmlEngine.

Calls C++ function: virtual [destructor] void QQmlEngine::~QQmlEngine().

C++ documentation:

Destroys the QQmlEngine.

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

See QJSEngine docs for details on cleaning up the JS engine.

impl Deref for QQmlEngine

type Target = QJSEngine

The resulting type after dereferencing.

fn deref(&self) -> &QJSEngine

Calls C++ function: QJSEngine* static_cast<QJSEngine*>(QQmlEngine* ptr).

impl DynamicCast<QQmlApplicationEngine> for QQmlEngine

unsafe fn dynamic_cast(ptr: Ptr<QQmlEngine>) -> Ptr<QQmlApplicationEngine>

Calls C++ function: QQmlApplicationEngine* dynamic_cast<QQmlApplicationEngine*>(QQmlEngine* ptr).

impl DynamicCast<QQmlEngine> for QJSEngine

unsafe fn dynamic_cast(ptr: Ptr<QJSEngine>) -> Ptr<QQmlEngine>

Calls C++ function: QQmlEngine* dynamic_cast<QQmlEngine*>(QJSEngine* ptr).

impl DynamicCast<QQmlEngine> for QObject

unsafe fn dynamic_cast(ptr: Ptr<QObject>) -> Ptr<QQmlEngine>

Calls C++ function: QQmlEngine* dynamic_cast<QQmlEngine*>(QObject* ptr).

impl StaticDowncast<QQmlApplicationEngine> for QQmlEngine

unsafe fn static_downcast(ptr: Ptr<QQmlEngine>) -> Ptr<QQmlApplicationEngine>

Calls C++ function: QQmlApplicationEngine* static_cast<QQmlApplicationEngine*>(QQmlEngine* ptr).

impl StaticDowncast<QQmlEngine> for QJSEngine

unsafe fn static_downcast(ptr: Ptr<QJSEngine>) -> Ptr<QQmlEngine>

Calls C++ function: QQmlEngine* static_cast<QQmlEngine*>(QJSEngine* ptr).

impl StaticDowncast<QQmlEngine> for QObject

unsafe fn static_downcast(ptr: Ptr<QObject>) -> Ptr<QQmlEngine>

Calls C++ function: QQmlEngine* static_cast<QQmlEngine*>(QObject* ptr).

impl StaticUpcast<QJSEngine> for QQmlEngine

unsafe fn static_upcast(ptr: Ptr<QQmlEngine>) -> Ptr<QJSEngine>

Calls C++ function: QJSEngine* static_cast<QJSEngine*>(QQmlEngine* ptr).

impl StaticUpcast<QObject> for QQmlEngine

unsafe fn static_upcast(ptr: Ptr<QQmlEngine>) -> Ptr<QObject>

Calls C++ function: QObject* static_cast<QObject*>(QQmlEngine* ptr).

impl StaticUpcast<QQmlEngine> for QQmlApplicationEngine

unsafe fn static_upcast(ptr: Ptr<QQmlApplicationEngine>) -> Ptr<QQmlEngine>

Calls C++ function: QQmlEngine* static_cast<QQmlEngine*>(QQmlApplicationEngine* ptr).