The QMetaObject class stores meta information about objects. More...

Public Methods
virtual QMetaClassInfo	classInfo (int index) const = 0

virtual int	classInfoCount () const = 0

int	classInfoOffset () const

virtual const QString &	className () const = 0

virtual QMetaMethod	constructor (int index) const = 0

virtual int	constructorCount () const = 0

virtual QMetaEnum	enumerator (int index) const = 0

virtual int	enumeratorCount () const = 0

int	enumeratorOffset () const

int	indexOfClassInfo (const QString &name) const

int	indexOfConstructor (const QString &constructor) const

int	indexOfEnumerator (const QString &name) const

int	indexOfMethod (const QString &method) const

int	indexOfProperty (const QString &name) const

int	indexOfSignal (const QString &signal) const

int	indexOfSlot (const QString &slot) const

virtual QMetaMethod	method (int index) const = 0

virtual int	methodCount () const = 0

int	methodOffset () const

template<class... Ts>
QObject *	newInstance (Ts...Vs) const

virtual QMetaProperty	property (int index) const = 0

virtual int	propertyCount () const = 0

int	propertyOffset () const

virtual const QMetaObject *	superClass () const = 0

QString	tr (const char text, const char comment=nullptr, std::optional< int > numArg=std::optional< int >()) const

QString	tr (const QString &text, const QString &comment=QString (), std::optional< int > numArg=std::optional< int >()) const

QMetaProperty	userProperty () const

Static Public Methods
static bool	checkConnectArgs (const QString &signal, const QString &method)

static void	connectSlotsByName (QObject *object)

template<class... Ts>
static bool	invokeMethod (QObject *object, const QString &member, CSArgument< Ts >...Vs)

template<class R , class... Ts>
static bool	invokeMethod (QObject *object, const QString &member, CSReturnArgument< R > retval, CSArgument< Ts >...Vs)

template<class... Ts>
static bool	invokeMethod (QObject *object, const QString &member, Qt::ConnectionType type, CSArgument< Ts >...Vs)

template<class R , class... Ts>
static bool	invokeMethod (QObject *object, const QString &member, Qt::ConnectionType type, CSReturnArgument< R > retval, CSArgument< Ts >...Vs)

static QString	normalizedSignature (const QString &method)

static QString	normalizedType (const QString &type)

Detailed Description

The QMetaObject class stores meta information about objects.

The CopperSpice Meta Object System is responsible for the signals and slots inter-object communication mechanism, runtime type information, and the CopperSpice property system. A single QMetaObject instance is created for each QObject subclass that is used in an application, and this instance stores all the meta information for the QObject subclass. This object is available as QObject::metaObject().

The most commonly used methods are shown below.

className() returns the name of a class.
superClass() returns the superclass meta object.
method() and methodCount() provide information about class meta methods (signals, slots and other invokable member functions).
enumerator() and enumeratorCount() and provide information about class enumerators.
propertyCount() and property() provide information about class properties.
constructor() and constructorCount() provide information about class meta constructors.

The index methods indexOfConstructor(), indexOfMethod(), indexOfEnumerator(), and indexOfProperty() map names of constructors, methods, enumerators, or properties to indexes in the meta object.

Classes can also have a list of name / value pairs of additional class information which is stored in QMetaClassInfo objects. The number of pairs is returned by classInfoCount() and single pairs are returned by classInfo(). You can search for pairs using the indexOfClassInfo() method.

See also: QMetaClassInfo, QMetaEnum, QMetaMethod, QMetaProperty, Meta Object System

Method Documentation

bool QMetaObject::checkConnectArgs	(	const QString &	signal,
		const QString &	method
	)

static

Returns true if the signal and method arguments are compatible, otherwise returns false. Both signal and method are expected to be normalized.

See also: normalizedSignature()

QMetaClassInfo QMetaObject::classInfo ( int index ) const

pure virtual

Returns the meta data for the item of class information with the given index.

class MyClass : public QObject
{
  CS_OBJECT(MyClass)
 
  CS_CLASSINFO("author", "Ray Bradbury")
  CS_CLASSINFO("url",    "http://www.raybradbury.com/about.html")
 
public:
  // ...
};

See also: classInfoCount(), classInfoOffset(), indexOfClassInfo()

int QMetaObject::classInfoCount ( ) const

pure virtual

Returns the number of items of class information in this class.

See also: classInfo(), classInfoOffset(), indexOfClassInfo()

int QMetaObject::classInfoOffset ( ) const

Returns the class information offset for this class. If the class has no parent with class information the offset is 0, otherwise the offset is the sum of all the class information items in all parent classes.

See also: classInfo(), classInfoCount(), indexOfClassInfo()

const QString & QMetaObject::className ( ) const

pure virtual

Returns the class name.

See also: superClass()

void QMetaObject::connectSlotsByName ( QObject * object )

static

This method searches recursively for all child objects of the specified object and creates a connection from any matching signal to the corresponding slot.

void on_<object name>_<signal name>(<signal parameters>);

For example, assume the given object has a child named myButton which is of type QPushButton. If you have a slot declared as shown below this method will create the connection automatically.

public:
   CS_SLOT_1(Private, void on_myButton_clicked())
   CS_SLOT_2(on_myButton_clicked)

See also: QObject::setObjectName()

QMetaMethod QMetaObject::constructor ( int index ) const

pure virtual

Returns the meta data for the constructor with the given index.

See also: constructorCount(), newInstance()

int QMetaObject::constructorCount ( ) const

pure virtual

Returns the number of constructors in this class.

See also: constructor(), indexOfConstructor()

QMetaEnum QMetaObject::enumerator ( int index ) const

pure virtual

Returns the meta data for the enumerator with the given index.

See also: enumeratorCount(), enumeratorOffset(), indexOfEnumerator()

int QMetaObject::enumeratorCount ( ) const

pure virtual

Returns the number of enumerators in this class.

See also: enumerator(), enumeratorOffset(), indexOfEnumerator()

int QMetaObject::enumeratorOffset ( ) const

Returns the enumerator offset for this class. If the class has no parents with enumerators the offset is 0, otherwise the offset is the sum of all the enumerators in all parent classes.

See also: enumerator(), enumeratorCount(), indexOfEnumerator()

int QMetaObject::indexOfClassInfo ( const QString & name ) const

Finds class information item name and returns its index, otherwise returns -1.

See also: classInfo(), classInfoCount(), classInfoOffset()

int QMetaObject::indexOfConstructor ( const QString & constructor ) const

Finds constructor and returns its index, otherwise returns -1. The constructor must be in normalized form as returned by normalizedSignature().

See also: constructor(), constructorCount(), normalizedSignature()

int QMetaObject::indexOfEnumerator ( const QString & name ) const

Finds enumerator name and returns its index, otherwise returns -1.

See also: enumerator(), enumeratorCount(), enumeratorOffset()

int QMetaObject::indexOfMethod ( const QString & method ) const

Finds method and returns its index, otherwise returns -1. The method must be in normalized form as returned by normalizedSignature().

See also: method(), methodCount(), methodOffset(), normalizedSignature()

int QMetaObject::indexOfProperty ( const QString & name ) const

Finds property name and returns its index, otherwise returns -1.

See also: property(), propertyCount(), propertyOffset()

int QMetaObject::indexOfSignal ( const QString & signal ) const

Finds signal and returns its index, otherwise returns -1. The signal must be in normalized form, as returned by normalizedSignature(). This is the same as indexOfMethod() except it will return -1 if the method exists but is not a signal.

See also: indexOfMethod(), normalizedSignature(), method(), methodCount(), methodOffset()

int QMetaObject::indexOfSlot ( const QString & slot ) const

Finds slot and returns its index, otherwise returns -1. This is the same as indexOfMethod(), except that it will return -1 if the method exists but is not a slot.

See also: indexOfMethod(), method(), methodCount(), methodOffset()

template<class... Ts>

bool QMetaObject::invokeMethod	(	QObject *	object,
		const QString &	member,
		CSArgument< Ts >...	Vs
	)

static

This overload invokes the member using the connection type Qt::AutoConnection and ignores return values.

template<class R , class... Ts>

bool QMetaObject::invokeMethod	(	QObject *	object,
		const QString &	member,
		CSReturnArgument< R >	retval,
		CSArgument< Ts >...	Vs
	)

static

This overload always invokes the member using the connection type Qt::AutoConnection.

template<class... Ts>

bool QMetaObject::invokeMethod	(	QObject *	object,
		const QString &	member,
		Qt::ConnectionType	type,
		CSArgument< Ts >...	Vs
	)

static

This overload can be used if the return value of the member is of no interest.

template<class R , class... Ts>

bool QMetaObject::invokeMethod	(	QObject *	object,
		const QString &	member,
		Qt::ConnectionType	type,
		CSReturnArgument< R >	retval,
		CSArgument< Ts >...	Vs
	)

static

Invokes the member (a signal or a slot name) on the given object. Returns true if the member could be invoked. Returns false if there is no such member or the parameters did not match. The invocation can be either synchronous or asynchronous, depending on the given type.

If type is Qt::DirectConnection, the member will be invoked immediately.
If type is Qt::QueuedConnection, a QEvent will be sent and the member is invoked as soon as the application enters the main event loop.
If type is Qt::BlockingQueuedConnection, the method will be invoked in the same way as for Qt::QueuedConnection, except that the current thread will block until the event is delivered. Using this connection type to communicate between objects in the same thread will lead to deadlocks.
If type is Qt::AutoConnection, the member is invoked synchronously if obj lives in the same thread as the caller, otherwise it will invoke the member asynchronously.

The return value is placed in retval. You must enclose the return value in a Q_RETURN_ARG() macro. Q_RETURN_ARG() takes a type name and a non-const reference. If the invocation is asynchronous there is no return value. You only need to pass the name of the signal or slot to this method not the entire signature. For example, to asynchronously invoke the animateClick() slot on a QPushButton, use the following code.

QMetaObject::invokeMethod(pushButton, "animateClick", Qt::QueuedConnection);

To synchronously invoke the compute(QString, int, double) slot on some arbitrary object obj retrieve its return value. If the "compute" slot does not take exactly one QString, one int, and one double in the specified order, the call will fail.

QString retval;

QMetaObject::invokeMethod(object, "compute", Qt::DirectConnection, Q_RETURN_ARG(QString, retval), QString("sqrt"), 42, 9.7);

See also: Q_RETURN_ARG(), QMetaMethod::invoke()

QMetaMethod QMetaObject::method ( int index ) const

pure virtual

Returns the meta data for the method with the given index.

See also: methodCount(), methodOffset(), indexOfMethod()

int QMetaObject::methodCount ( ) const

pure virtual

Returns the number of methods known to the meta object system in this class, including the number of properties provided by each base class. These include signals and slots as well as member functions declared with the CS_INVOKABLE() macro.

Use code like the following to obtain a QStringList containing the methods specific to a given class.

const QMetaObject * metaObject = obj->metaObject();
QStringList methods;
 
for(int i = metaObject->methodOffset(); i < metaObject->methodCount(); ++i) {
   methods << metaObject->method(i).signature();
}

See also: method(), methodOffset(), indexOfMethod()

int QMetaObject::methodOffset ( ) const

Returns the method offset for this class. The offset is the sum of all the methods in the class superclasses (which is always positive since QObject has the deleteLater() slot and a destroyed() signal).

See also: method(), methodCount(), indexOfMethod()

template<class... Ts>

QObject * QMetaObject::newInstance ( Ts... Vs ) const

Constructs a new instance of this class. Returns the new object or a nullptr if no suitable constructor is available. Only constructors that are declared with the CS_INVOKABLE() modifier are made available through the meta object system.

See also: constructor()

QString QMetaObject::normalizedSignature ( const QString & method )

static

Normalizes the signature of the given method.

CopperSpice uses normalized signatures to decide whether a given signal and slot are compatible. Normalization reduces whitespace to a minimum, moves 'const' to the front where appropriate, removes 'const' from value types, and for a parameter replaces a const reference with a value.

QString str = "mySlot(int const &) const";

QString normalStr = QMetaObject::normalizedSignature(str); // returns "mySlot(int)"

See also: checkConnectArgs(), normalizedType()

QString QMetaObject::normalizedType ( const QString & type )

static

Normalizes a data type.

QString normType = QMetaObject::normalizedType(" int const *"); // return "const int*"

See also: normalizedSignature()

QMetaProperty QMetaObject::property ( int index ) const

pure virtual

Returns the meta data for the property with the given index. If no such property exists, a null QMetaProperty is returned.

See also: propertyCount(), propertyOffset(), indexOfProperty()

int QMetaObject::propertyCount ( ) const

pure virtual

Returns the number of properties in this class, including the number of properties provided by each base class. The following example can be used to obtain a QStringList containing the properties specific to a given class.

const QMetaObject * metaObject = obj->metaObject();
QStringList properties;
 
for (int i = metaObject->propertyOffset(); i < metaObject->propertyCount(); ++i)  {
    properties << metaObject->property(i).name();
}

See also: property(), propertyOffset(), indexOfProperty()

int QMetaObject::propertyOffset ( ) const

Returns the property offset for this class. The offset is the sum of all the properties in the class superclasses (which is always positive since QObject has the name() property).

See also: property(), propertyCount(), indexOfProperty()

const QMetaObject * QMetaObject::superClass ( ) const

pure virtual

Returns the meta object of the superclass or nullptr if there is no object.

See also: className()

QString QMetaObject::tr	(	const char *	text,
		const char *	comment = `nullptr`,
		std::optional< int >	numArg = `std::optional<int>()`
	)		const

Returns a translated version of text which is based on the given comment and the value of numArg for translations containing numbers. Returns the original given text if no translation is available.

QString QMetaObject::tr	(	const QString &	text,
		const QString &	comment = `QString()`,
		std::optional< int >	numArg = `std::optional<int>()`
	)		const

Returns a translated version of text which is based on the given comment and the value of numArg for translations containing numbers. Returns the original given text if no translation is available.

QMetaProperty QMetaObject::userProperty ( ) const

Returns the property where the USER flag is set to true. There should be only one property with the User flag set for a particular class and any parent classes.

See also: QMetaProperty::isUser()

Public Methods

Static Public Methods

Detailed Description

Method Documentation