The QSignalMapper class bundles signals from identifiable senders. More...

Inheritance diagram for QSignalMapper:

Public Signals
void	mapped (const QString &text)

void	mapped (int index)

void	mapped (QObject *object)

void	mapped (QWidget *widget)

Public Signals inherited from QObject
void	destroyed (QObject *obj=nullptr)

void	objectNameChanged (const QString &objectName)

Public Slots
void	map ()

void	map (QObject *sender)

Public Slots inherited from QObject
void	deleteLater ()

Public Methods
	QSignalMapper (QObject *parent=nullptr)

	~QSignalMapper ()

QObject *	mapping (const QString &text) const

QObject *	mapping (int id) const

QObject *	mapping (QObject *object) const

QObject *	mapping (QWidget *widget) const

void	removeMappings (QObject *sender)

void	setMapping (QObject *sender, const QString &text)

void	setMapping (QObject *sender, int id)

void	setMapping (QObject sender, QObject object)

void	setMapping (QObject sender, QWidget widget)

Public Methods inherited from QObject
	QObject (QObject *parent=nullptr)

	~QObject ()

bool	blockSignals (bool block)

const QList< QObject * > &	children () const

bool	connect (const QObject *sender, const QString &signalMethod, const QString &location, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	connect (const QObject *sender, const QString &signalMethod, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	disconnect (const QObject *receiver, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod, const QString &location, const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod=QString (), const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QString >	dynamicPropertyNames () const

virtual bool	event (QEvent *event)

virtual bool	eventFilter (QObject watched, QEvent event)

template<typename T >
T	findChild (const QString &childName=QString ()) const

template<class T >
QList< T >	findChildren (const QRegularExpression &regExp, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

template<class T >
QList< T >	findChildren (const QString &childName=QString (), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

bool	inherits (const QString &className) const

void	installEventFilter (QObject *filterObj)

bool	isWidgetType () const

bool	isWindowType () const

void	killTimer (int id)

const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

QString	objectName () const

QObject *	parent () const

template<class T = QVariant>
T	property (const QString &name) const

void	removeEventFilter (QObject *obj)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const QString &name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)

QThread *	thread () const

Additional Inherited Members
Static Public Methods inherited from QObject
static bool	connect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

static bool	connect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection, const QString &location=QString ())

static bool	connect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...), Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotLambda, Qt::ConnectionType type=Qt::AutoConnection)

static bool	disconnect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, std::nullptr_t, const QObject receiver, std::nullptr_t)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...))

template<class Sender , class SignalClass , class... SignalArgs, class Receiver >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, std::nullptr_t slotMethod=nullptr)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotMethod)

static QMetaObject &	staticMetaObject ()

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

Protected Methods inherited from QObject
virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const QMetaMethod &signalMethod) const

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const QMetaMethod &signalMethod) const

bool	isSignalConnected (const QMetaMethod &signalMethod) const

int	receivers (const QString &signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Properties inherited from QObject
	objectName

Related Functions inherited from QObject
T	qobject_cast (QObject *object)

	QObjectList

Detailed Description

The QSignalMapper class bundles signals from identifiable senders. This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal.

The class supports the mapping of particular strings or integers with particular objects using setMapping(). The objects' signals can then be connected to the map() slot which will emit the mapped() signal with the string or integer associated with the original signaling object. Mappings can be removed later using removeMappings().

Example

Suppose we want to create a custom widget that contains a group of buttons (like a tool palette). One approach is to connect each button's clicked() signal to its own custom slot; but in this example we want to connect all the buttons to a single slot and parameterize the slot by the button that was clicked.

Here is the definition of a simple custom widget that has a single signal, clicked(), which is emitted with the text of the button that was clicked.

class ButtonWidget : public QWidget {
    CS_OBJECT(ButtonWidget)
 
    public:
       ButtonWidget(QStringList texts, QWidget *parent = nullptr);
 
       CS_SIGNAL_1(Public, void clicked(const QString &text))
       CS_SIGNAL_2(clicked, text)
 
    private:
          QSignalMapper *signalMapper;
};

The only function that we need to implement is the constructor:

ButtonWidget::ButtonWidget(QStringList texts, QWidget *parent) : QWidget(parent)
{
    signalMapper = new QSignalMapper(this);
 
    QGridLayout *gridLayout = new QGridLayout;
    for (int i = 0; i < texts.size(); ++i) {
        QPushButton *button = new QPushButton(texts[i]);
        connect(button, SIGNAL(clicked()), signalMapper, SLOT(map()));
        signalMapper->setMapping(button, texts[i]);
        gridLayout->addWidget(button, i / 3, i % 3);
    }
 
    connect(signalMapper, SIGNAL(mapped(const QString &)), this, SIGNAL(clicked(const QString &)));
 
    setLayout(gridLayout);
}

A list of texts is passed to the constructor. A signal mapper is constructed and for each text in the list a QPushButton is created. We connect each button's clicked() signal to the signal mapper's map() slot, and create a mapping in the signal mapper from each button to the button's text. Finally we connect the signal mapper's mapped() signal to the custom widget's clicked() signal. When the user clicks a button, the custom widget will emit a single clicked() signal whose argument is the text of the button the user clicked.

See also: QObject, QButtonGroup, QActionGroup

Constructor & Destructor Documentation

QSignalMapper::QSignalMapper ( QObject * parent = nullptr )

explicit

Constructs a QSignalMapper with the given parent.

QSignalMapper::~QSignalMapper ( )

Destroys the QSignalMapper.

Method Documentation

void QSignalMapper::map ( )

slot

This slot emits signals based on which object sends signals to it.

void QSignalMapper::map ( QObject * sender )

slot

This slot emits signals based on the sender object.

void QSignalMapper::mapped ( const QString & text )

signal

This signal is emitted when map() is signalled from an object that has a string mapping set. The object's mapped string is passed in text.

See also: setMapping()

void QSignalMapper::mapped ( int index )

signal

This signal is emitted when map() is signalled from an object that has an integer mapping set. The object's mapped integer is passed in index.

See also: setMapping()

void QSignalMapper::mapped ( QObject * object )

signal

This signal is emitted when map() is signalled from an object that has an object mapping set. The object provided by the map is passed in object.

See also: setMapping()

void QSignalMapper::mapped ( QWidget * widget )

signal

This signal is emitted when map() is signalled from an object that has a widget mapping set. The object's mapped widget is passed in widget.

See also: setMapping()

QObject * QSignalMapper::mapping ( const QString & text ) const

Returns the sender QObject associated with the given text.

QObject * QSignalMapper::mapping ( int id ) const

Returns the sender QObject associated with the given id.

See also: setMapping()

QObject * QSignalMapper::mapping ( QObject * object ) const

Returns the sender QObject that is associated with the object.

QObject * QSignalMapper::mapping ( QWidget * widget ) const

Returns the sender QObject that is associated with the widget.

void QSignalMapper::removeMappings ( QObject * sender )

Removes all mappings for sender. This is done automatically when mapped objects are destroyed.

void QSignalMapper::setMapping	(	QObject *	sender,
		const QString &	text
	)

Adds a mapping so when map() is triggered from the sender, the signal mapped(text) is emitted. There may be at most one text for each sender.

void QSignalMapper::setMapping	(	QObject *	sender,
		int	id
	)

Adds a mapping so when map() is triggered from the given sender, the signal mapped(id) is emitted. There may be at most one integer ID for each sender.

See also: mapping()

void QSignalMapper::setMapping	(	QObject *	sender,
		QObject *	object
	)

Adds a mapping so when map() is triggered from the sender, the signal mapped(object) is emitted. There may be at most one object for each sender.

void QSignalMapper::setMapping	(	QObject *	sender,
		QWidget *	widget
	)

Adds a mapping so when map() is triggered from the sender, the signal mapped(widget) is emitted. There may be at most one widget for each sender.

Public Signals

Public Slots

Public Methods

Additional Inherited Members

Detailed Description

Example

Constructor & Destructor Documentation

Method Documentation