QSplitter Class Reference
^{[QtGui module]}

Detailed Description

The QSplitter class implements a splitter widget.

A splitter lets the user control the size of child widgets by dragging the boundary between the children. Any number of widgets may be controlled by a single splitter. The typical use of a QSplitter is to create several widgets and add them using insertWidget() or addWidget().

The following example will show a QListView, QTreeView, and QTextEdit side by side, with two splitter handles:

     QSplitter *splitter = new QSplitter(parent);
     QListView *listview = new QListView;
     QTreeView *treeview = new QTreeView;
     QTextEdit *textedit = new QTextEdit;
     splitter->addWidget(listview);
     splitter->addWidget(treeview);
     splitter->addWidget(textedit);

If a widget is already inside a QSplitter when insertWidget() or addWidget() is called, it will move to the new position. This can be used to reorder widgets in the splitter later. You can use indexOf(), widget(), and count() to get access to the widgets inside the splitter.

A default QSplitter lays out its children horizontally (side by side); you can use setOrientation(Qt::Vertical) to lay its children out vertically.

By default, all widgets can be as large or as small as the user wishes, between the minimumSizeHint() (or minimumSize()) and maximumSize() of the widgets.

QSplitter resizes its children dynamically by default. If you would rather have QSplitter resize the children only at the end of a resize operation, call setOpaqueResize(false).

The initial distribution of size between the widgets is determined by the initial size of each widget. You can also use setSizes() to set the sizes of all the widgets. The function sizes() returns the sizes set by the user. Alternatively, you can save and restore the sizes of the widgets from a QByteArray using saveState() and restoreState() respectively.

When you hide() a child its space will be distributed among the other children. It will be reinstated when you show() it again.

See also QSplitterHandle, QHBoxLayout, QVBoxLayout, and QTabWidget.

Property Documentation

childrenCollapsible : bool

This property holds whether child widgets can be resized down to size 0 by the user.

By default, children are collapsible. It is possible to enable and disable the collapsing of individual children using setCollapsible().

Access functions:

• bool childrenCollapsible () const
• void setChildrenCollapsible ( bool )

See also setCollapsible().

handleWidth : int

This property holds the width of the splitter handles.

Access functions:

• int handleWidth () const
• void setHandleWidth ( int )

opaqueResize : bool

This property holds whether resizing is opaque.

Opaque resizing is on by default.

Access functions:

• bool opaqueResize () const
• void setOpaqueResize ( bool opaque = true )

orientation : Qt::Orientation

This property holds the orientation of the splitter.

By default the orientation is horizontal (i.e., the widgets are laid out side by side). The possible orientations are Qt::Horizontal and Qt::Vertical.

Access functions:

• Qt::Orientation orientation () const
• void setOrientation ( Qt::Orientation )

See also QSplitterHandle::orientation().

Member Function Documentation

QSplitter::QSplitter ( QWidget * parent = 0 )

Constructs a horizontal splitter with the parent arguments is passed on to the QFrame constructor.

See also setOrientation().

QSplitter::QSplitter ( Qt::Orientation orientation, QWidget * parent = 0 )

Constructs a splitter with the given orientation and parent.

See also setOrientation().

QSplitter::~QSplitter ()

Destroys the splitter. All children are deleted.

void QSplitter::addWidget ( QWidget * widget )

Adds the given widget to the splitter's layout after all the other items.

If widget is already in the splitter, it will be moved to the new position.

See also insertWidget(), widget(), and indexOf().

int QSplitter::closestLegalPosition ( int pos, int index )   [protected]

Returns the closest legal position to pos of the widget with index index.

For right-to-left languages such as Arabic and Hebrew, the layout of horizontal splitters is reversed. Positions are then measured from the right edge of the widget.

See also getRange().

int QSplitter::count () const

Returns the number of widgets contained in the splitter's layout.

See also widget() and handle().

QSplitterHandle * QSplitter::createHandle ()   [virtual protected]

Returns a new splitter handle as a child widget of this splitter. This function can be reimplemented in subclasses to provide support for custom handles.

See also handle() and indexOf().

void QSplitter::getRange ( int index, int * min, int * max ) const

Returns the valid range of the splitter with index index in *min and *max if min and max are not 0.

QSplitterHandle * QSplitter::handle ( int index ) const

Returns the handle to the left (or above) for the item in the splitter's layout at the given index. The handle at index 0 is always hidden.

For right-to-left languages such as Arabic and Hebrew, the layout of horizontal splitters is reversed. The handle will be to the right of the widget at index.

See also count(), widget(), indexOf(), createHandle(), and setHandleWidth().

int QSplitter::indexOf ( QWidget * widget ) const

Returns the index in the splitter's layout of the specified widget. This also works for handles.

Handles are numbered from 0. There are as many handles as there are child widgets, but the handle at position 0 is always hidden.

See also count() and widget().

void QSplitter::insertWidget ( int index, QWidget * widget )

Inserts the widget specified into the splitter's layout at the given index.

If widget is already in the splitter, it will be moved to the new position.

if index is an invalid index, then the widget will be inserted at the end.

See also addWidget(), indexOf(), and widget().

bool QSplitter::isCollapsible ( int index ) const

Returns true if the widget at index is collapsible, otherwise returns false

void QSplitter::moveSplitter ( int pos, int index )   [protected]

Moves the left or top edge of the splitter handle at index as close as possible to position pos, which is the distance from the left or top edge of the widget.

For right-to-left languages such as Arabic and Hebrew, the layout of horizontal splitters is reversed. pos is then the distance from the right edge of the widget.

See also splitterMoved(), closestLegalPosition(), and getRange().

void QSplitter::refresh ()

Updates the splitter's state. You should not need to call this function.

bool QSplitter::restoreState ( const QByteArray & state )

Restores the splitter's layout to the state specified. Returns true if the state is restored; otherwise returns false.

Typically this is used in conjunction with QSettings to restore the size from a past session. Here is an example:

Restore the splitters's state:

     QSettings settings;
     splitter->restoreState(settings.value("splitterSizes").toByteArray());

A failure to restore the splitter's layout may result from either invalid or out-of-date data in the supplied byte array.

See also saveState().

QByteArray QSplitter::saveState () const

Saves the state of the splitter's layout.

Typically this is used in conjunction with QSettings to remember the size for a future session. A version number is stored as part of the data. Here is an example:

     QSettings settings;
     settings.setValue("splitterSizes", splitter->saveState());

See also restoreState().

void QSplitter::setCollapsible ( int index, bool collapse )

Sets whether the child widget at index index is collapsible to collapse.

By default, children are collapsible, meaning that the user can resize them down to size 0, even if they have a non-zero minimumSize() or minimumSizeHint(). This behavior can be changed on a per-widget basis by calling this function, or globally for all the widgets in the splitter by setting the childrenCollapsible property.

See also isCollapsible() and childrenCollapsible.

void QSplitter::setRubberBand ( int pos )   [protected]

Displays a rubber band at position pos. If pos is negative, the rubber band is removed.

void QSplitter::setSizes ( const QList<int> & list )

Sets the size parameters to the values given in the list. If the splitter is horizontal, the values set the widths of each widget going from left to right. If the splitter is vertical, the values set the heights of each widget going from top to bottom. Extra values in the list are ignored.

If list contains too few values, the result is undefined but the program will still be well-behaved.

The values in list should be the height or width (depending on orientation()) that the widgets should be resized to.

See also sizes().

void QSplitter::setStretchFactor ( int index, int stretch )

Updates the size policy of the widget at position index to have a stretch factor of stretch.

This function is provided for convenience. It is equivalent to

 QWidget *widget = splitter->widget(index);
 QSizePolicy policy = widget->sizePolicy();
 policy.setHorizontalStretch(stretch);
 policy.setVerticalStretch(stretch);
 widget->setSizePolicy(policy);

See also setSizes() and widget().

QList<int> QSplitter::sizes () const

Returns a list of the size parameters of all the widgets in this splitter.

If the splitter's orientation is horizontal, the list is a list of widget widths; if the orientation is vertical, the list is a list of widget heights.

Giving the values to another splitter's setSizes() function will produce a splitter with the same layout as this one.

The easiest way to iterate over the list is to use the Java-style iterators.

     QListIterator<int> it(splitter->sizes());
     while (it.hasNext())
         processSize(it.next());

See also setSizes().

void QSplitter::splitterMoved ( int pos, int index )   [signal]

This signal is emitted when the splitter handle at a particular index has been moved to position pos.

For right-to-left languages such as Arabic and Hebrew, the layout of horizontal splitters is reversed. pos is then the distance from the right edge of the widget.

See also moveSplitter().

QWidget * QSplitter::widget ( int index ) const

Returns the widget at the given index in the splitter's layout.

See also count(), handle(), indexOf(), and insertWidget().

Member Type Documentation

enum QSplitter::ResizeMode

This enum describes the different resizing behaviors child widgets can have:

Use setStretchFactor() instead.

Member Function Documentation

QSplitter::QSplitter ( QWidget * parent, const char * name )

Use one of the constructors that doesn't take the name argument and then use setObjectName() instead.

QSplitter::QSplitter ( Qt::Orientation orientation, QWidget * parent, const char * name )

Use one of the constructors that don't take the name argument and then use setObjectName() instead.

int QSplitter::margin () const

Returns the with of the the margin around the contents of the widget.

Use QWidget::getContentsMargins() instead.

See also setMargin() and QWidget::getContentsMargins().

void QSplitter::moveToFirst ( QWidget * widget )

Use insertWidget(0, widget) instead.

void QSplitter::moveToLast ( QWidget * widget )

Use addWidget(widget) instead.

void QSplitter::setCollapsible ( QWidget * widget, bool collapsible )

This is an overloaded member function, provided for convenience.

Use setCollapsible(indexOf(widget, collapsible)) instead.

void QSplitter::setMargin ( int margin )

Sets the width of the margin around the contents of the widget to margin.

Use QWidget::setContentsMargins() instead.

See also margin() and QWidget::setContentsMargins().

void QSplitter::setResizeMode ( QWidget * widget, ResizeMode mode )

Use setStretchFactor() instead.

For example, if you have code like

 splitter->setResizeMode(firstChild, QSplitter::KeepSize);
 splitter->setResizeMode(secondChild, QSplitter::Stretch);

you can rewrite it as

 splitter->setStretchFactor(splitter->indexOf(firstChild), 0);
 splitter->setStretchFactor(splitter->indexOf(secondChild), 1);