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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...

Inherits QLayout.

### Types

- enum StackingMode { StackOne, StackAll }

### Methods

- __init__ (self)
- __init__ (self, QWidget parent)
- __init__ (self, QLayout parentLayout)
- addItem (self, QLayoutItem item)
- int addWidget (self, QWidget w)
- int count (self)
- int currentIndex (self)
- QWidget currentWidget (self)
- int insertWidget (self, int index, QWidget w)
- QLayoutItem itemAt (self, int)
- QSize minimumSize (self)
- setCurrentIndex (self, int index)
- setCurrentWidget (self, QWidget w)
- setGeometry (self, QRect rect)
- setStackingMode (self, StackingMode stackingMode)
- QSize sizeHint (self)
- StackingMode stackingMode (self)
- QLayoutItem takeAt (self, int)
- QWidget widget (self, int)
- QWidget widget (self)

### Qt Signals

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

## 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"). For example:

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

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

         QVBoxLayout *mainLayout = new QVBoxLayout;
         mainLayout->addLayout(stackedLayout);
         setLayout(mainLayout);

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)),
                 stackedLayout, SLOT(setCurrentIndex(int)));

When populating a layout, 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 layout. The number of widgets contained in the layout, 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 layout changes or a widget is removed from the layout, the currentChanged() and widgetRemoved() signals are emitted respectively.

## Type Documentation

### QStackedLayout.StackingMode

This enum specifies how the layout handles its child widgets regarding their visibility.

Constant | Value | Description
--- | --- | ---
`QStackedLayout.StackOne` | `0` | Only the current widget is visible. This is the default.
`QStackedLayout.StackAll` | `1` | All widgets are visible. The current widget is merely raised.

This enum was introduced or modified in Qt 4.4.

## Method Documentation

### QStackedLayout.__init__ (self)

Constructs a QStackedLayout with no parent.

This QStackedLayout must be installed on a widget later on to become effective.

See also addWidget() and insertWidget().

### QStackedLayout.__init__ (self, QWidget parent)

The parent argument, if not None, causes self to be owned by Qt instead of PyQt.

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.__init__ (self, QLayout parentLayout)

The parentLayout argument, if not None, causes self to be owned by Qt instead of PyQt.

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

### QStackedLayout.addItem (self, QLayoutItem item)

The item argument has it's ownership transferred to Qt.

Reimplemented from QLayout.addItem().

### int QStackedLayout.addWidget (self, QWidget w)

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

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

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

### int QStackedLayout.count (self)

### int QStackedLayout.currentIndex (self)

### QWidget QStackedLayout.currentWidget (self)

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

See also currentIndex() and setCurrentWidget().

### int QStackedLayout.insertWidget (self, int index, QWidget w)

Inserts the given widget at the given index in this QStackedLayout. 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 QStackedLayout is 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().

### QLayoutItem QStackedLayout.itemAt (self, int)

Reimplemented from QLayout.itemAt().

### QSize QStackedLayout.minimumSize (self)

Reimplemented from QLayoutItem.minimumSize().

### QStackedLayout.setCurrentIndex (self, int index)

This method is also a Qt slot with the C++ signature `void setCurrentIndex(int)`.

### QStackedLayout.setCurrentWidget (self, QWidget w)

This method is also a Qt slot with the C++ signature `void setCurrentWidget( ::QWidget*)`.

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

See also setCurrentIndex() and currentWidget().

### QStackedLayout.setGeometry (self, QRect rect)

Reimplemented from QLayoutItem.setGeometry().

### QStackedLayout.setStackingMode (self, StackingMode stackingMode)

### QSize QStackedLayout.sizeHint (self)

Reimplemented from QLayoutItem.sizeHint().

### StackingMode QStackedLayout.stackingMode (self)

### QLayoutItem QStackedLayout.takeAt (self, int)

The QLayoutItem result

Reimplemented from QLayout.takeAt().

### QWidget QStackedLayout.widget (self, int)

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

See also currentWidget() and indexOf().

### QWidget QStackedLayout.widget (self)

## Qt Signal Documentation

### void currentChanged (int)

This is the default overload of this signal.

This signal is emitted whenever the current widget in the layout changes. The index specifies 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 QStackedLayout)

See also currentWidget() and setCurrentWidget().

### void widgetRemoved (int)

This is the default overload of this signal.

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

See also removeWidget().