QDeclarativeNetworkAccessManagerFactory ¶

PySide.QtDeclarative.QDeclarativeNetworkAccessManagerFactory class creates PySide.QtNetwork.QNetworkAccessManager instances for a QML engine.

A QML engine uses PySide.QtNetwork.QNetworkAccessManager for all network access. By implementing a factory, it is possible to provide the QML engine with custom PySide.QtNetwork.QNetworkAccessManager instances with specialized caching, proxy and cookies support.

To implement a factory, subclass PySide.QtDeclarative.QDeclarativeNetworkAccessManagerFactory and implement the virtual PySide.QtDeclarative.QDeclarativeNetworkAccessManagerFactory.create() method, then assign it to the relevant QML engine using QDeclarativeEngine.setNetworkAccessManagerFactory() .

Note the QML engine may create PySide.QtNetwork.QNetworkAccessManager instances from multiple threads. Because of this, the implementation of the PySide.QtDeclarative.QDeclarativeNetworkAccessManagerFactory.create() method must be 可重入 . In addition, the developer should be careful if the signals of the object to be returned from PySide.QtDeclarative.QDeclarativeNetworkAccessManagerFactory.create() are connected to the slots of an object that may be created in a different thread:

• The QML engine internally handles all requests, and cleans up any PySide.QtNetwork.QNetworkReply objects it creates. Receiving the QNetworkAccessManager.finished() signal in another thread may not provide the receiver with a valid reply object if it has already been deleted.
• Authentication details provided to QNetworkAccessManager.authenticationRequired() must be provided immediately, so this signal cannot be connected as a Qt.QueuedConnection (or as the default Qt.AutoConnection from another thread).

For more information about signals and threads, see 线程和 QObject and 信号和槽跨线程 .