QQmlEngine¶

The QQmlEngine class provides an environment for instantiating QML components. More…

Inherited by: QQmlApplicationEngine

Synopsis¶

Functions¶

def addImageProvider (id, arg__2)
def addImportPath (dir)
def addNamedBundle (arg__1, arg__2)
def addPluginPath (dir)
def addUrlInterceptor (urlInterceptor)
def baseUrl ()
def captureProperty (object, property)
def clearComponentCache ()
def imageProvider (id)
def importPathList ()
def importPlugin (filePath, uri, errors)
def incubationController ()
def interceptUrl (url, type)
def networkAccessManager ()
def networkAccessManagerFactory ()
def offlineStorageDatabaseFilePath (databaseName)
def offlineStoragePath ()
def outputWarningsToStandardError ()
def pluginPathList ()
def removeImageProvider (id)
def removeUrlInterceptor (urlInterceptor)
def rootContext ()
def setBaseUrl (arg__1)
def setImportPathList (paths)
def setIncubationController (arg__1)
def setNetworkAccessManagerFactory (arg__1)
def setOfflineStoragePath (dir)
def setOutputWarningsToStandardError (arg__1)
def setPluginPathList (paths)
def setUrlInterceptor (urlInterceptor)
def trimComponentCache ()
def urlInterceptor ()
def urlInterceptors ()

Slots¶

def retranslate ()

Signals¶

def exit (retCode)
def quit ()
def warnings (warnings)

Static functions¶

def contextForObject (arg__1)
def setContextForObject (arg__1, arg__2)

Detailed Description¶

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 .

See also

QQmlComponent QQmlContext QML Global Object

class PySide6.QtQml.QQmlEngine([p=None])¶

Parameters: p – PySide6.QtCore.QObject

Create a new QQmlEngine with the given parent.

PySide6.QtQml.QQmlEngine.addImageProvider(id, arg__2)¶

Parameters

id – str
arg__2 – PySide6.QtQml.QQmlImageProviderBase

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 QQmlImageProviderBase

PySide6.QtQml.QQmlEngine.addImportPath(dir)¶

Parameters: dir – str

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() QML Modules

PySide6.QtQml.QQmlEngine.addNamedBundle(arg__1, arg__2)¶

Parameters

arg__1 – str
arg__2 – str

Return type

bool

Note

This function is deprecated.

PySide6.QtQml.QQmlEngine.addPluginPath(dir)¶

Parameters: dir – str

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()

PySide6.QtQml.QQmlEngine.addUrlInterceptor(urlInterceptor)¶

Parameters: urlInterceptor – PySide6.QtQml.QQmlAbstractUrlInterceptor

Adds a urlInterceptor to be used when resolving URLs in QML. This also applies to URLs used for loading script files and QML types. The URL interceptors should not be modifed while the engine is loading files, or URL selection may be inconsistent. Multiple URL interceptors, when given, will be called in the order they were added for each URL.

QQmlEngine does not take ownership of the interceptor and won’t delete it.

PySide6.QtQml.QQmlEngine.baseUrl()¶

Return type: PySide6.QtCore.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.

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

See also

setBaseUrl()

PySide6.QtQml.QQmlEngine.captureProperty(object, property)¶

Parameters

object – PySide6.QtCore.QObject
property – PySide6.QtCore.QMetaProperty

PySide6.QtQml.QQmlEngine.clearComponentCache()¶

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.

Note

Any existing objects created from QML components retain their types, even if you clear the component cache. This includes singleton objects. If you create more objects from the same QML code after clearing the cache, the new objects will be of different types than the old ones. Assigning such a new object to a property of its declared type belonging to an object created before clearing the cache won’t work.

As a general rule of thumb, make sure that no objects created from QML components are alive when you clear the component cache.

See also

trimComponentCache()

static PySide6.QtQml.QQmlEngine.contextForObject(arg__1)¶

Parameters: arg__1 – PySide6.QtCore.QObject
Return type: PySide6.QtQml.QQmlContext

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() qmlEngine()

PySide6.QtQml.QQmlEngine.exit(retCode)¶

Parameters: retCode – int

PySide6.QtQml.QQmlEngine.imageProvider(id)¶

Parameters: id – str
Return type: PySide6.QtQml.QQmlImageProviderBase

Returns the image provider set for providerId if found; otherwise returns None.

See also

QQuickImageProvider

PySide6.QtQml.QQmlEngine.importPathList()¶

Return type: list of strings

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 QML_IMPORT_PATH environment variable, and the builtin QmlImportsPath from QLibraryInfo .

See also

addImportPath() setImportPathList()

PySide6.QtQml.QQmlEngine.importPlugin(filePath, uri, errors)¶

Parameters

filePath – str
uri – str
errors – QList

Return type

bool

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 QQmlEngineExtensionPlugin interface.

PySide6.QtQml.QQmlEngine.incubationController()¶

Return type: PySide6.QtQml.QQmlIncubationController

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

See also

setIncubationController()

PySide6.QtQml.QQmlEngine.interceptUrl(url, type)¶

Parameters

url – PySide6.QtCore.QUrl
type – DataType

Return type

PySide6.QtCore.QUrl

Run the current URL interceptors on the given url of the given type and return the result.

PySide6.QtQml.QQmlEngine.networkAccessManager()¶

Return type: PySide6.QtNetwork.QNetworkAccessManager

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

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

See also

setNetworkAccessManagerFactory()

PySide6.QtQml.QQmlEngine.networkAccessManagerFactory()¶

Return type: PySide6.QtQml.QQmlNetworkAccessManagerFactory

Returns the current QQmlNetworkAccessManagerFactory .

See also

setNetworkAccessManagerFactory()

PySide6.QtQml.QQmlEngine.offlineStorageDatabaseFilePath(databaseName)¶

Parameters: databaseName – str
Return type: str

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

See also

LocalStorage.openDatabaseSync()

PySide6.QtQml.QQmlEngine.offlineStoragePath()¶

Return type: str

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 mkpath() .

PySide6.QtQml.QQmlEngine.outputWarningsToStandardError()¶

Return type: bool

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()

PySide6.QtQml.QQmlEngine.pluginPathList()¶

Return type: list of strings

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() setPluginPathList()

PySide6.QtQml.QQmlEngine.quit()¶

PySide6.QtQml.QQmlEngine.removeImageProvider(id)¶

Parameters: id – str

Removes the image provider for providerId.

See also

addImageProvider() QQuickImageProvider

PySide6.QtQml.QQmlEngine.removeUrlInterceptor(urlInterceptor)¶

Parameters: urlInterceptor – PySide6.QtQml.QQmlAbstractUrlInterceptor

Remove a urlInterceptor that was previously added using addUrlInterceptor . The URL interceptors should not be modifed while the engine is loading files, or URL selection may be inconsistent.

This does not delete the interceptor, but merely removes it from the engine. You can re-use it on the same or a different engine afterwards.

PySide6.QtQml.QQmlEngine.retranslate()¶

Refreshes all binding expressions that use strings marked for translation.

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

PySide6.QtQml.QQmlEngine.rootContext()¶

Return type: PySide6.QtQml.QQmlContext

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.

PySide6.QtQml.QQmlEngine.setBaseUrl(arg__1)¶

Parameters: arg__1 – PySide6.QtCore.QUrl

Set the base URL for this engine to url.

See also

baseUrl()

static PySide6.QtQml.QQmlEngine.setContextForObject(arg__1, arg__2)¶

Parameters

arg__1 – PySide6.QtCore.QObject
arg__2 – PySide6.QtQml.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.

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

See also

contextForObject()

PySide6.QtQml.QQmlEngine.setImportPathList(paths)¶

Parameters: paths – list of strings

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 QmlImportsPath from QLibraryInfo .

See also

importPathList() addImportPath()

PySide6.QtQml.QQmlEngine.setIncubationController(arg__1)¶

Parameters: arg__1 – PySide6.QtQml.QQmlIncubationController

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()

PySide6.QtQml.QQmlEngine.setNetworkAccessManagerFactory(arg__1)¶

Parameters: arg__1 – PySide6.QtQml.QQmlNetworkAccessManagerFactory

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.

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QQmlEngine¶

Synopsis¶

Functions¶

Slots¶

Signals¶

Static functions¶

Detailed Description¶