QButtonGroup Class Reference

The QButtonGroup class provides a container to organize groups of button widgets. More...

#include <qbuttongroup.h>

Inheritance diagram for QButtonGroup:

Signals
void	buttonClicked (QAbstractButton *)
	This signal is emitted when the given button is clicked. More...
void	buttonClicked (int)
	This signal is emitted when a button with the given id is clicked. More...
void	buttonPressed (QAbstractButton *)
void	buttonPressed (int)
	This signal is emitted when a button with the given id is pressed down. More...
void	buttonReleased (QAbstractButton *)
void	buttonReleased (int)
	This signal is emitted when a button with the given id is released. More...
Signals inherited from QObject
void	destroyed (QObject *=0)
	This signal is emitted immediately before the object obj is destroyed, and can not be blocked. More...

Public Functions
void	addButton (QAbstractButton *)
	Adds the given button to the end of the group's internal list of buttons. More...
void	addButton (QAbstractButton *, int id)
	Adds the given button to the button group, with the given id. More...
QAbstractButton *	button (int id) const
QList< QAbstractButton * >	buttons () const
	Returns the list of this groups's buttons. More...
QAbstractButton *	checkedButton () const
	Returns the button group's checked button, or 0 if no buttons are checked. More...
int	checkedId () const
	Returns the id of the checkedButton(), or -1 if no button is checked. More...
bool	exclusive () const
int	id (QAbstractButton *button) const
	QButtonGroup (QObject *parent=0)
	Constructs a new, empty button group with the given parent. More...
void	removeButton (QAbstractButton *)
	Removes the given button from the button group. More...
void	setExclusive (bool)
void	setId (QAbstractButton *button, int id)
	~QButtonGroup ()
	Destroys the button group. More...
Public Functions inherited from QObject
bool	blockSignals (bool b)
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). More...
const QObjectList &	children () const
	Returns a list of child objects. More...
bool	connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
bool	disconnect (const char *signal=0, const QObject *receiver=0, const char *member=0)
bool	disconnect (const QObject *receiver, const char *member=0)
void	dumpObjectInfo ()
	Dumps information about signal connections, etc. More...
void	dumpObjectTree ()
	Dumps a tree of children to the debug output. More...
QList< QByteArray >	dynamicPropertyNames () const
	Returns the names of all properties that were dynamically added to the object using setProperty(). More...
virtual bool	event (QEvent *)
	This virtual function receives events to an object and should return true if the event e was recognized and processed. More...
virtual bool	eventFilter (QObject *, QEvent *)
	Filters events if this object has been installed as an event filter for the watched object. More...
template<typename T >
T	findChild (const QString &aName=QString()) const
	Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. More...
template<typename T >
QList< T >	findChildren (const QString &aName=QString()) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. More...
template<typename T >
QList< T >	findChildren (const QRegExp &re) const
bool	inherits (const char *classname) const
	Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false. More...
void	installEventFilter (QObject *)
	Installs an event filter filterObj on this object. More...
bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false. More...
void	killTimer (int id)
	Kills the timer with timer identifier, id. More...
virtual const QMetaObject *	metaObject () const
	Returns a pointer to the meta-object of this object. More...
void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children. More...
QString	objectName () const
QObject *	parent () const
	Returns a pointer to the parent object. More...
QVariant	property (const char *name) const
	Returns the value of the object's name property. More...
Q_INVOKABLE	QObject (QObject *parent=0)
	Constructs an object with parent object parent. More...
void	removeEventFilter (QObject *)
	Removes an event filter object obj from this object. More...
void	setObjectName (const QString &name)
void	setParent (QObject *)
	Makes the object a child of parent. More...
bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value. More...
void	setUserData (uint id, QObjectUserData *data)
bool	signalsBlocked () const
	Returns true if signals are blocked; otherwise returns false. More...
int	startTimer (int interval)
	Starts a timer and returns a timer identifier, or returns zero if it could not start a timer. More...
QThread *	thread () const
	Returns the thread in which the object lives. More...
QObjectUserData *	userData (uint id) const
virtual	~QObject ()
	Destroys the object, deleting all its child objects. More...

Properties
bool	exclusive
	whether the button group is exclusive More...

Friends
class	QAbstractButton
class	QAbstractButtonPrivate

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()
	Schedules this object for deletion. More...
Static Public Functions inherited from QObject
static bool	connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
	Creates a connection of the given type from the signal in the sender object to the method in the receiver object. More...
static bool	connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
static bool	disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
	Disconnects signal in object sender from method in object receiver. More...
static bool	disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
static uint	registerUserData ()
static QString	tr (const char *sourceText, const char *comment=0, int n=-1)
static QString	trUtf8 (const char *sourceText, const char *comment=0, int n=-1)
Static Public Variables inherited from QObject
static const QMetaObject	staticMetaObject
	This variable stores the meta-object for the class. More...
Protected Functions inherited from QObject
virtual void	childEvent (QChildEvent *)
	This event handler can be reimplemented in a subclass to receive child events. More...
virtual void	connectNotify (const char *signal)
	This virtual function is called when something has been connected to signal in this object. More...
virtual void	customEvent (QEvent *)
	This event handler can be reimplemented in a subclass to receive custom events. More...
virtual void	disconnectNotify (const char *signal)
	This virtual function is called when something has been disconnected from signal in this object. More...
	QObject (QObjectPrivate &dd, QObject *parent=0)
int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal. More...
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns 0. More...
int	senderSignalIndex () const
virtual void	timerEvent (QTimerEvent *)
	This event handler can be reimplemented in a subclass to receive timer events for the object. More...
Protected Variables inherited from QObject
QScopedPointer< QObjectData >	d_ptr
Static Protected Variables inherited from QObject
static const QMetaObject	staticQtMetaObject
Related Functions inherited from QObject
T	qFindChildqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()
QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QRegExp &regExp)()
T *	qobject_cast (QObject *object)
	QObjectList
void *	qt_find_obj_child (QObject *parent, const char *type, const QString &name)
	Returns a pointer to the object named name that inherits type and with a given parent. More...

Detailed Description

The QButtonGroup class provides a container to organize groups of button widgets.

QButtonGroup provides an abstract container into which button widgets can be placed. It does not provide a visual representation of this container (see QGroupBox for a container widget), but instead manages the states of each of the buttons in the group.

An QButtonGroup::exclusive {exclusive} button group switches off all checkable (toggle) buttons except the one that was clicked. By default, a button group is exclusive. The buttons in a button group are usually checkable QPushButton's, (normally for non-exclusive button groups), or QRadioButton . If you create an exclusive button group, you should ensure that one of the buttons in the group is initially checked; otherwise, the group will initially be in a state where no buttons are checked.

A button is added to the group with addButton(). It can be removed from the group with removeButton(). If the group is exclusive, the currently checked button is available as checkedButton(). If a button is clicked the buttonClicked() signal is emitted. For a checkable button in an exclusive group this means that the button was checked. The list of buttons in the group is returned by buttons().

In addition, QButtonGroup can map between integers and buttons. You can assign an integer id to a button with setId(), and retrieve it with id(). The id of the currently checked button is available with checkedId(), and there is an overloaded signal buttonClicked() which emits the id of the button. The id {-1} is reserved by QButtonGroup to mean "no such button". The purpose of the mapping mechanism is to simplify the representation of enum values in a user interface.

See also

QGroupBox QPushButton, QCheckBox, QRadioButton

Definition at line 59 of file qbuttongroup.h.

Constructors and Destructors

QButtonGroup()

QButtonGroup::QButtonGroup ( QObject *  parent = 0 )

explicit

Constructs a new, empty button group with the given parent.

See also

addButton() setExclusive()

Definition at line 198 of file qabstractbutton.cpp.

    : QObject(*new QButtonGroupPrivate, parent)
{
}

~QButtonGroup()

QButtonGroup::~QButtonGroup

(

)

Destroys the button group.

Definition at line 203 of file qabstractbutton.cpp.

{
    Q_D(QButtonGroup);
    for (int i = 0; i < d->buttonList.count(); ++i)
        d->buttonList.at(i)->d_func()->group = 0;
}

Functions

addButton() [1/2]

void QButtonGroup::addButton

(

QAbstractButton *

button

)

Adds the given button to the end of the group's internal list of buttons.

An id will be assigned to the button by this QButtonGroup. Automatically assigned ids are guaranteed to be negative, starting with -2. If you are also assigning your own ids, use positive values to avoid conflicts.

See also

removeButton() buttons()

Definition at line 225 of file qabstractbutton.cpp.

Referenced by QPrintDialogPrivate::setupDestination(), and QPrintDialogPrivate::setupPrinterSettings().

{
    addButton(button, -1);
}

addButton() [2/2]

void QButtonGroup::addButton	(	QAbstractButton *	button,
		int	id
	)

Adds the given button to the button group, with the given id.

It is recommended to assign only positive ids.

See also

removeButton() buttons()

Definition at line 230 of file qabstractbutton.cpp.

{
    Q_D(QButtonGroup);
    if (QButtonGroup *previous = button->d_func()->group)
        previous->removeButton(button);
    button->d_func()->group = this;
    d->buttonList.append(button);
    if (id == -1) {
        QList<int> ids = d->mapping.values();
        if (ids.isEmpty())
           d->mapping[button] = -2;
        else {
            qSort(ids);
            d->mapping[button] = ids.first()-1;
        }
    } else {
        d->mapping[button] = id;
    }

    if (d->exclusive && button->isChecked())
        button->d_func()->notifyChecked();
}

button()

QAbstractButton * QButtonGroup::button

(

int

id

)

const

Since

4.1

Returns the button with the specified id, or 0 if no such button exists.

Definition at line 278 of file qabstractbutton.cpp.

Referenced by addButton(), QAbstractButtonPrivate::moveFocus(), and setId().

{
    Q_D(const QButtonGroup);
    return d->mapping.key(id);
}

buttonClicked [1/2]

void QButtonGroup::buttonClicked ( QAbstractButton *  button )

signal

This signal is emitted when the given button is clicked.

A button is clicked when it is first pressed and then released, when its shortcut key is typed, or programmatically when QAbstractButton::click() or QAbstractButton::animateClick() is called.

See also

checkedButton(), QAbstractButton::clicked()

buttonClicked [2/2]

void QButtonGroup::buttonClicked ( int  id )

signal

This signal is emitted when a button with the given id is clicked.

See also

checkedButton(), QAbstractButton::clicked()

buttonPressed [1/2]

void QButtonGroup::buttonPressed ( QAbstractButton *  button )

signal

Since

4.2

This signal is emitted when the given button is pressed down.

See also

QAbstractButton::pressed()

buttonPressed [2/2]

void QButtonGroup::buttonPressed ( int  id )

signal

This signal is emitted when a button with the given id is pressed down.

Since

4.2

See also

QAbstractButton::pressed()

buttonReleased [1/2]

void QButtonGroup::buttonReleased ( QAbstractButton *  button )

signal

Since

4.2

This signal is emitted when the given button is released.

See also

QAbstractButton::released()

buttonReleased [2/2]

void QButtonGroup::buttonReleased ( int  id )

signal

This signal is emitted when a button with the given id is released.

Since

4.2

See also

QAbstractButton::released()

buttons()

QList< QAbstractButton * > QButtonGroup::buttons

(

)

const

Returns the list of this groups's buttons.

This may be empty.

See also

addButton(), removeButton()

Definition at line 266 of file qabstractbutton.cpp.

{
    Q_D(const QButtonGroup);
    return d->buttonList;
}

checkedButton()

QAbstractButton * QButtonGroup::checkedButton

(

)

const

Returns the button group's checked button, or 0 if no buttons are checked.

See also

buttonClicked()

Definition at line 272 of file qabstractbutton.cpp.

Referenced by QButtonGroupPrivate::detectCheckedButton().

{
    Q_D(const QButtonGroup);
    return d->checkedButton;
}

checkedId()

int QButtonGroup::checkedId

(

)

const

Returns the id of the checkedButton(), or -1 if no button is checked.

Since

4.1

See also

setId()

Definition at line 297 of file qabstractbutton.cpp.

{
    Q_D(const QButtonGroup);
    return d->mapping.value(d->checkedButton, -1);
}

exclusive()

bool QButtonGroup::exclusive

(

)

const

Referenced by QButtonGroupPrivate::detectCheckedButton(), QAbstractButtonPrivate::moveFocus(), setExclusive(), and ~QButtonGroup().

id()

int QButtonGroup::id

(

QAbstractButton *

button

)

const

Since

4.1

Returns the id for the specified button, or -1 if no such button exists.

See also

setId()

Definition at line 291 of file qabstractbutton.cpp.

Referenced by addButton(), and setId().

{
    Q_D(const QButtonGroup);
    return d->mapping.value(button, -1);
}

removeButton()

void QButtonGroup::removeButton

(

QAbstractButton *

button

)

Removes the given button from the button group.

See also

addButton() buttons()

Definition at line 253 of file qabstractbutton.cpp.

{
    Q_D(QButtonGroup);
    if (d->checkedButton == button) {
        d->detectCheckedButton();
    }
    if (button->d_func()->group == this) {
        button->d_func()->group = 0;
        d->buttonList.removeAll(button);
        d->mapping.remove(button);
    }
}

setExclusive()

void QButtonGroup::setExclusive

(

bool

exclusive

)

Definition at line 217 of file qabstractbutton.cpp.

{
    Q_D(QButtonGroup);
    d->exclusive = exclusive;
}

setId()

void QButtonGroup::setId	(	QAbstractButton *	button,
		int	id
	)

Since

4.1

Sets the id for the specified button. Note that id can not be -1.

See also

id()

Definition at line 284 of file qabstractbutton.cpp.

{
    Q_D(QButtonGroup);
    if (button && id != -1)
        d->mapping[button] = id;
}

Friends and Related Functions

QAbstractButton

friend class QAbstractButton

friend

Definition at line 102 of file qbuttongroup.h.

QAbstractButtonPrivate

friend class QAbstractButtonPrivate

friend

Definition at line 103 of file qbuttongroup.h.

Properties

exclusive

QButtonGroup::exclusive

private

whether the button group is exclusive

If this property is true then only one button in the group can be checked at any given time. The user can click on any button to check it, and that button will replace the existing one as the checked button in the group.

In an exclusive group, the user cannot uncheck the currently checked button by clicking on it; instead, another button in the group must be clicked to set the new checked button for that group.

By default, this property is true.

Definition at line 63 of file qbuttongroup.h.

---

The documentation for this class was generated from the following files:

• /src/gui/widgets/qbuttongroup.h
• /src/gui/widgets/qabstractbutton.cpp
• /src/gui/widgets/qbuttongroup.cpp