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-rw-r--r--src/qml/doc/src/qmlfunctions.qdoc97
1 files changed, 95 insertions, 2 deletions
diff --git a/src/qml/doc/src/qmlfunctions.qdoc b/src/qml/doc/src/qmlfunctions.qdoc
index ab54b5fd1d..9c106558fd 100644
--- a/src/qml/doc/src/qmlfunctions.qdoc
+++ b/src/qml/doc/src/qmlfunctions.qdoc
@@ -487,8 +487,7 @@
A QObject singleton type may be referenced via the type name with which it was registered, and this
typename may be used as the target in a \l Connections type or otherwise used as any other type id would.
- One exception to this is that a QObject singleton type property may not be aliased (because the
- singleton type name does not identify an object within the same component as any other item).
+ One exception to this is that a QObject singleton type property may not be aliased.
\b{NOTE:} A QObject singleton type instance returned from a singleton type provider is owned by
the QML engine unless the object has explicit QQmlEngine::CppOwnership flag set.
@@ -619,6 +618,100 @@
*/
/*!
+ \fn int qmlRegisterSingletonInstance(const char *uri, int versionMajor, int
+ versionMinor, const char *typeName, QObject* cppObject)
+ \relates QQmlEngine
+ \since 5.14
+
+ This function is used to register a singleton object \a cppObject, with a
+ particular \a uri and \a typeName. Its version is a combination of \a
+ versionMajor and \a versionMinor.
+
+ Installing a singleton type into a URI allows you to provide arbitrary
+ functionality (methods and properties) to QML code without requiring
+ individual instances of the type to be instantiated by the client.
+
+ Use this function to register an object of the given type T as a singleton
+ type.
+
+ A QObject singleton type may be referenced via the type name with which it
+ was registered; in turn this type name may be used as the target in a \l
+ Connections type, or like any other type ID. However, there's one
+ exception: a QObject singleton type property can't be aliased because the
+ singleton type name does not identify an object within the same component
+ as any other item.
+
+ \note \a cppObject must outlive the QML engine in which it is used.
+ Moreover, \cppObject must have the same thread affinity as the engine. If
+ you want separate singleton instances for multiple engines, you need to use
+ \l {qmlRegisterSingletonType}. See \l{Threads and QObjects} for more
+ information about thread safety.
+
+ Usage:
+ \code
+ // First, define your QObject which provides the functionality.
+ class SingletonTypeExample : public QObject
+ {
+ Q_OBJECT
+ Q_PROPERTY(int someProperty READ someProperty WRITE setSomeProperty NOTIFY somePropertyChanged)
+
+ public:
+ explicit SingletonTypeExample(QObject* parent = nullptr) : QObject(parent) {}
+
+ Q_INVOKABLE int doSomething()
+ {
+ setSomeProperty(5);
+ return m_someProperty;
+ }
+
+ int someProperty() const { return m_someProperty; }
+ void setSomeProperty(int val) {
+ if (m_someProperty != val) {
+ m_someProperty = val;
+ emit somePropertyChanged(val);
+ }
+ }
+
+ signals:
+ void somePropertyChanged(int newValue);
+
+ private:
+ int m_someProperty = 0;
+ };
+ \endcode
+
+ \code
+ // Second, create an instance of the object
+
+ // allocate example before the engine to ensure that it outlives it
+ QScopedPointer<SingletonTypeExample> example(new SingletonTypeExample);
+ QQmlEngine engine;
+
+ // Third, register the singleton type provider with QML by calling this
+ // function in an initialization function.
+ qmlRegisterSingletonInstance("Qt.example.qobjectSingleton", 1, 0, "MyApi", example.get());
+ \endcode
+
+
+ In order to use the registered singleton type in QML, you must import the
+ URI with the corresponding version.
+ \qml
+ import QtQuick 2.0
+ import Qt.example.qobjectSingleton 1.0
+ Item {
+ id: root
+ property int someValue: MyApi.someProperty
+
+ Component.onCompleted: {
+ console.log(MyApi.doSomething())
+ }
+ }
+ \endqml
+
+ \sa qmlRegisterSingletonType
+ */
+
+/*!
\fn int qmlRegisterType(const QUrl &url, const char *uri, int versionMajor, int versionMinor, const char *qmlName);
\relates QQmlEngine