Qt 4.3: QStackedWidget Class Reference

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# QStackedWidget Class Reference
[QtGui module]

The QStackedWidget class provides a stack of widgets where only one widget is visible at a time. More...

     #include <QStackedWidget>

Inherits QFrame.

- List of all members, including inherited members

### Properties

- count : const int
- currentIndex : int

- 6 properties inherited from QFrame
- 56 properties inherited from QWidget
- 1 property inherited from QObject

### Public Functions

- QStackedWidget ( QWidget * parent = 0 )
- ~QStackedWidget ()
- int addWidget ( QWidget * widget )
- int count () const
- int currentIndex () const
- QWidget * currentWidget () const
- int indexOf ( QWidget * widget ) const
- int insertWidget ( int index, QWidget * widget )
- void removeWidget ( QWidget * widget )
- QWidget * widget ( int index ) const

- 13 public functions inherited from QFrame
- 201 public functions inherited from QWidget
- 29 public functions inherited from QObject
- 12 public functions inherited from QPaintDevice

### Public Slots

- void setCurrentIndex ( int index )
- void setCurrentWidget ( QWidget * widget )

- 19 public slots inherited from QWidget
- 1 public slot inherited from QObject

### Signals

- void currentChanged ( int index )
- void widgetRemoved ( int index )

- 1 signal inherited from QWidget
- 1 signal inherited from QObject

### Additional Inherited Members

- 4 static public members inherited from QWidget
- 5 static public members inherited from QObject
- 38 protected functions inherited from QWidget
- 7 protected functions inherited from QObject
- 1 protected function inherited from QPaintDevice
- 1 protected slot inherited from QWidget

## Detailed Description

The QStackedWidget class provides a stack of widgets where only one widget is visible at a time.

QStackedWidget can be used to create a user interface similar to the one provided by QTabWidget. It is a convenience layout widget built on top of the QStackedLayout class.

Like QStackedLayout, QStackedWidget can be constructed and populated with a number of child widgets ("pages"):

         QWidget *firstPageWidget = new QWidget;
         QWidget *secondPageWidget = new QWidget;
         QWidget *thirdPageWidget = new QWidget;

         QStackedWidget *stackedWidget = new QStackedWidget;
         stackedWidget->addWidget(firstPageWidget);
         stackedWidget->addWidget(secondPageWidget);
         stackedWidget->addWidget(thirdPageWidget);

         QVBoxLayout *layout = new QVBoxLayout;
         layout->addWidget(stackedWidget);
         setLayout(layout);

QStackedWidget provides no intrinsic means for the user to switch page. This is typically done through a QComboBox or a QListWidget that stores the titles of the QStackedWidget's pages. For example:

         QComboBox *pageComboBox = new QComboBox;
         pageComboBox->addItem(tr("Page 1"));
         pageComboBox->addItem(tr("Page 2"));
         pageComboBox->addItem(tr("Page 3"));
         connect(pageComboBox, SIGNAL(activated(int)),
                 stackedWidget, SLOT(setCurrentIndex(int)));

When populating a stacked widget, the widgets are added to an internal list. The indexOf() function returns the index of a widget in that list. The widgets can either be added to the end of the list using the addWidget() function, or inserted at a given index using the insertWidget() function. The removeWidget() function removes the widget at the given index from the stacked widget. The number of widgets contained in the stacked widget, can be obtained using the count() function.

The widget() function returns the widget at a given index position. The index of the widget that is shown on screen is given by currentIndex() and can be changed using setCurrentIndex(). In a similar manner, the currently shown widget can be retrieved using the currentWidget() function, and altered using the setCurrentWidget() function.

Whenever the current widget in the stacked widget changes or a widget is removed from the stacked widget, the currentChanged() and widgetRemoved() signals are emitted respectively.

See also QStackedLayout, QTabWidget, and Config Dialog Example.

## Property Documentation

### count : const int

This property holds the number of widgets contained by this stacked widget.

Access functions:

- int count () const

See also currentIndex() and widget().

### currentIndex : int

This property holds the index position of the widget that is visible.

The current index is -1 if there is no current widget.

Access functions:

- int currentIndex () const
- void setCurrentIndex ( int index )

See also currentWidget() and indexOf().

## Member Function Documentation

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

Constructs a QStackedWidget with the given parent.

See also addWidget() and insertWidget().

### QStackedWidget::~QStackedWidget ()

Destroys this stacked widget, and frees any allocated resources.

### int QStackedWidget::addWidget ( QWidget * widget )

Appends the given widget to this QStackedWidget and returns the index position.

If the QStackedWidget is empty before this function is called, widget becomes the current widget.

See also insertWidget(), removeWidget(), and setCurrentWidget().

### void QStackedWidget::currentChanged ( int index ) `[signal]`

This signal is emitted whenever the current widget changes.

The parameter holds the index of the new current widget, or -1 if there isn't a new one (for example, if there are no widgets in the QStackedWidget).

See also currentWidget() and setCurrentWidget().

### QWidget * QStackedWidget::currentWidget () const

Returns the current widget, or 0 if there are no child widgets.

See also currentIndex() and setCurrentWidget().

### int QStackedWidget::indexOf ( QWidget * widget ) const

Returns the index of the given widget, or -1 if the given widget is not a child of this QStackedWidget.

See also currentIndex() and widget().

### int QStackedWidget::insertWidget ( int index, QWidget * widget )

Inserts the given widget at the given index in this QStackedWidget. If index is out of range, the widget is appended (in which case it is the actual index of the widget that is returned).

If the QStackedWidget was empty before this function is called, the given widget becomes the current widget.

Inserting a new widget at an index less than or equal to the current index will increment the current index, but keep the current widget.

See also addWidget(), removeWidget(), and setCurrentWidget().

### void QStackedWidget::removeWidget ( QWidget * widget )

Removes the given widget from this QStackedWidget. The widget is not deleted.

See also addWidget(), insertWidget(), and currentWidget().

### void QStackedWidget::setCurrentWidget ( QWidget * widget ) `[slot]`

Sets the current widget to be the specified widget. The new current widget must already be contained in this stacked widget.

See also currentWidget() and setCurrentIndex().

### QWidget * QStackedWidget::widget ( int index ) const

Returns the widget at the given index, or 0 if there is no such widget.

See also currentWidget() and indexOf().

### void QStackedWidget::widgetRemoved ( int index ) `[signal]`

This signal is emitted whenever a widget is removed. The widget's index is passed as parameter.

See also removeWidget().