Qt 4.0: QStackedLayout Class Reference

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# QStackedLayout Class Reference
[QtGui module]

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

    #include <QStackedLayout>

Inherits QLayout.

- List of all members, including inherited members

### Properties

- count : const int
- currentIndex : int

- 3 properties inherited from QLayout
- 1 property inherited from QObject

### Public Functions

- QStackedLayout ()
- QStackedLayout ( QWidget * parent )
- QStackedLayout ( QLayout * parentLayout )
- ~QStackedLayout ()
- int addWidget ( QWidget * widget )
- virtual int count () const
- int currentIndex () const
- QWidget * currentWidget () const
- int insertWidget ( int index, QWidget * widget )
- QWidget * widget ( int index ) const

- 26 public functions inherited from QLayout
- 28 public functions inherited from QObject
- 16 public functions inherited from QLayoutItem

### Public Slots

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

- 1 public slot inherited from QObject

### Signals

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

- 1 signal inherited from QObject

### Additional Inherited Members

- 1 static public member inherited from QLayout
- 4 static public members inherited from QObject
- 3 protected functions inherited from QLayout
- 7 protected functions inherited from QObject

## Detailed Description

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

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

A QStackedLayout can be populated with a number of child widgets ("pages"):

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

        QStackedLayout *layout = new QStackedLayout;
        layout->addWidget(firstPageWidget);
        layout->addWidget(secondPageWidget);
        layout->addWidget(thirdPageWidget);
        setLayout(layout);

When inserted, the widgets are added to an internal list. The indexOf() function returns the index of a widget in that list. 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().

QStackedLayout 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 QStackedLayout'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)),
                layout, SLOT(setCurrentIndex(int)));

See also QStackedWidget and QTabWidget.

## Property Documentation

### count : const int

This property holds the number of widgets contained in the layout.

Access functions:

- virtual int count () const

### 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

### QStackedLayout::QStackedLayout ()

Constructs a QStackedLayout with no parent.

This QStackedLayout must be added to another layout later on to become effective.

### QStackedLayout::QStackedLayout ( QWidget * parent )

Constructs a new QStackedLayout with the given parent.

This layout will install itself on the parent widget and manage the geometry of its children.

### QStackedLayout::QStackedLayout ( QLayout * parentLayout )

Constructs a new QStackedLayout and inserts it into the given parentLayout.

### QStackedLayout::~QStackedLayout ()

Destroys this QStackedLayout.

The layout's widgets are not destroyed.

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

Adds widget to the end of this layout and returns the index position of widget.

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

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

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

This signal is emitted when the current widget in the layout changes. The index specifies the index of the new current widget.

See also currentWidget() and setCurrentWidget().

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

Returns the current widget, or 0 if there are no widgets in this layout.

Equivalent to widget(currentIndex()).

See also setCurrentWidget() and currentIndex().

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

Inserts widget at position index in this QStackedLayout. If index is out of range, the widget is appended. Returns the actual index of widget.

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

See also addWidget().

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

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

See also setCurrentIndex() and currentWidget().

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

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

See also currentWidget() and indexOf().

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

This signal is emitted when the widget at position index is removed from the layout.

See also removeWidget().