QQmlNetworkAccessManagerFactory Class

The QQmlNetworkAccessManagerFactory class creates QNetworkAccessManager instances for a QML engine. 更多...

头: #include <QQmlNetworkAccessManagerFactory>
CMake: find_package(Qt6 REQUIRED COMPONENTS Qml)
target_link_libraries(mytarget PRIVATE Qt6::Qml)
qmake: QT += qml

公共函数

virtual ~QQmlNetworkAccessManagerFactory ()
virtual QNetworkAccessManager * create (QObject * parent ) = 0

详细描述

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

To implement a factory, subclass QQmlNetworkAccessManagerFactory and implement the virtual create () method, then assign it to the relevant QML engine using QQmlEngine::setNetworkAccessManagerFactory (). For instance, the QNetworkAccessManager objects created by the following snippet will cache requests.

class CachingNetworkAccessManagerFactory : public QQmlNetworkAccessManagerFactory
{
public:
    inline QNetworkAccessManager *create(QObject *parent) override
    {
        QNetworkAccessManager *networkAccessManager = new QNetworkAccessManager(parent);
        QNetworkDiskCache *diskCache = new QNetworkDiskCache(parent);
        diskCache->setCacheDirectory("requestCache");
        networkAccessManager->setCache(diskCache);
        return networkAccessManager;
    }
};
					

The factory can then be passed to the QML engine so it can instantiate the QNetworkAccessManager with the custom behavior.

CachingNetworkAccessManagerFactory networkManagerFactory;
engine->setNetworkAccessManagerFactory(&networkManagerFactory);
					

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

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

另请参阅 QNetworkDiskCache .

成员函数文档编制

[virtual noexcept] QQmlNetworkAccessManagerFactory:: ~QQmlNetworkAccessManagerFactory ()

Destroys the factory. The default implementation does nothing.

[pure virtual] QNetworkAccessManager *QQmlNetworkAccessManagerFactory:: create ( QObject * parent )

Creates and returns a network access manager with the specified parent . This method must return a new QNetworkAccessManager instance each time it is called.

Note: this method may be called by multiple threads, so ensure the implementation of this method is reentrant.