Home | All Classes | Main Classes | Annotated | Grouped Classes | Functions |

# QCheckBox Class Reference

The QCheckBox widget provides a checkbox with a text label. More...

    #include <QCheckBox>

Inherits QAbstractButton.

- List of all members, including inherited members
- Compatibility members

### Public Types

- enum ToggleState { Off, NoChange, On }

### Writable Properties

- tristate : bool

- 8 writable properties inherited from QAbstractButton
- 33 writable properties inherited from QWidget
- 1 writable property inherited from QObject

### Read-Only Properties

- autoMask : bool

- 24 read-only properties inherited from QWidget

### Public Functions

- QCheckBox ( QWidget * parent = 0 )
- QCheckBox ( const QString & text, QWidget * parent = 0 )
- void setState ( ToggleState state )
- ToggleState state () const

- 1 public function inherited from QAbstractButton
- 83 public functions inherited from QWidget
- 24 public functions inherited from QObject
- 2 public functions inherited from QPaintDevice

### Public Slots

- 4 public slots inherited from QAbstractButton
- 16 public slots inherited from QWidget
- 1 public slot inherited from QObject

### Signals

- void stateChanged ( int state )

- 4 signals inherited from QAbstractButton
- 1 signal inherited from QObject

### Static Public Members

- 4 static public members inherited from QWidget
- 4 static public members inherited from QObject

### Protected Functions

- void drawBevel ( QPainter * paint )
- void drawLabel ( QPainter * p )
- virtual void paintEvent ( QPaintEvent * event )

- 3 protected functions inherited from QAbstractButton
- 44 protected functions inherited from QWidget
- 9 protected functions inherited from QObject

## Detailed Description

The QCheckBox widget provides a checkbox with a text label.

A QCheckBox is an option button that can be switched on (checked) or off (unchecked). Checkboxes are typically used to represent features in an application that can be enabled or disabled without affecting others, but different types of behavior can be implemented.

A QButtonGroup can be used to group check buttons visually.

Whenever a checkbox is checked or cleared it emits the signal stateChanged(). Connect to this signal if you want to trigger an action each time the checkbox changes state. You can use isChecked() to query whether or not a checkbox is checked.

In addition to the usual checked and unchecked states, QCheckBox optionally provides a third state to indicate "no change". This is useful whenever you need to give the user the option of neither checking nor unchecking a checkbox. If you need this third state, enable it with setTristate(), and use state() to query the current toggle state.

Just like QPushButton, a checkbox can display text or a pixmap. The text can be set in the constructor or with setText(); the pixmap is set with setPixmap().

Important inherited functions: text(), setText(), text(), pixmap(), setPixmap(), accel(), setAccel(), isToggleButton(), setDown(), isDown(), isOn(), state(), autoRepeat(), isExclusiveToggle(), group(), setAutoRepeat(), toggle(), pressed(), released(), clicked(), toggled(), state(), and stateChanged().

Fowler: Check Box

See also QButton and QRadioButton.

## Member Type Documentation

### enum QCheckBox::ToggleState

`QCheckBox::Off` |
`QCheckBox::NoChange` |
`QCheckBox::On` |

## Property Documentation

### autoMask : bool

This property holds whether the checkbox is automatically masked.

See also QWidget::setAutoMask().

### tristate : bool

This property holds whether the checkbox is a tri-state checkbox.

The default is false; i.e. the checkbox has only two states.

Access functions:

- bool isTristate () const
- void setTristate ( bool y = true )

## Member Function Documentation

### QCheckBox::QCheckBox ( QWidget * parent = 0 )

Constructs a checkbox with the given parent, but with no text.

The parent argument is passed on to the QAbstractButton constructor.

### QCheckBox::QCheckBox ( const QString & text, QWidget * parent = 0 )

Constructs a checkbox with the given parent and text.

The parent argument is passed on to the QAbstractButton constructor.

### void QCheckBox::drawBevel ( QPainter * paint ) `[protected]`

Draws the checkbox bevel on painter paint. Called from paintEvent().

See also drawLabel().

### void QCheckBox::drawLabel ( QPainter * p ) `[protected]`

Draws the check box label on painter p. Called from paintEvent().

See also drawBevel().

### void QCheckBox::paintEvent ( QPaintEvent * event ) `[virtual protected]`

Paints the button in response to the paint event, by first calling drawBevel() and then drawLabel(). If you reimplement paintEvent() in order to draw a different label only, you can call drawBevel() from your own code.

        QPainter p(this);
        drawBevel(&p);
        // ... your label drawing code

Reimplemented from QWidget.

### void QCheckBox::setState ( ToggleState state )

Sets the check box's toggle state to state.

See also state() and ToggleState.

### ToggleState QCheckBox::state () const

Returns the check box's toggle state.

See also setState() and ToggleState.

### void QCheckBox::stateChanged ( int state ) `[signal]`

This signal is emitted whenever the check box's state changes, i.e. whenever the user checks or unchecks it.

state contains the check box's new `ToggleState`.