QLayout(3qt)QLayout(3qt)NAME
QLayout - The base class of geometry specifiers
#include <qabstractlayout.h>
Inherits QLayoutItem and QObject.
Inherited by QBoxLayout and QGridLayout.
Public Members
QLayout ( QWidget * parent, int margin=0, int space=-1,
const char * name=0 )
QLayout ( QLayout * parentLayout, int space=-1, const char
* name=0 )
QLayout ( int space=-1, const char * name=0 )
~QLayout ()
int margin () const
int spacing () const
virtual void setMargin ( int )
virtual void setSpacing ( int )
enum { unlimited = QWIDGETSIZE_MAX }
enum ResizeMode { FreeResize, Minimum, Fixed }
void setResizeMode ( ResizeMode )
ResizeMode resizeMode () const
virtual void setMenuBar ( QMenuBar * w )
QMenuBar* menuBar () const
QWidget* mainWidget ()
bool isTopLevel () const
virtual void setAutoAdd ( bool )
bool autoAdd () const
virtual void invalidate ()
bool activate ()
void add ( QWidget * w )
virtual void addItem ( QLayoutItem * )
virtual QSizePolicy::ExpandData expanding () const
virtual QSize minimumSize () const
virtual QSize maximumSize () const
virtual void setGeometry ( const QRect & )
virtual QLayoutIterator iterator ()
virtual bool isEmpty () const
int totalHeightForWidth ( int w ) const (internal)
QSize totalMinimumSize () const (internal)
QSize totalMaximumSize () const (internal)
QSize totalSizeHint () const (internal)
bool supportsMargin () const
void setEnabled ( bool )
bool isEnabled () const
Protected Members
virtual bool eventFilter ( QObject *, QEvent * )
void addChildLayout ( QLayout * l )
void deleteAllItems ()
void setSupportsMargin ( bool )
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QLayout(3qt)QLayout(3qt)
QRect alignmentRect ( const QRect & ) const
Properties
Type Name READ WRITE Options
---------------------------------------------------------------
int margin margin setMargin
int spacing spacing setSpacing
ResizeMode resizeMode resizeMode setResizeMode
DESCRIPTION
The QLayout class is the base class of geometry
specifiers.
This is an abstract base class. The concrete layout
managers QBoxLayout and QGridLayout inherit from this one.
For users of Q*Layout or QMainWindow, there is seldom need
to use any of the basic functions provided by QLayout,
such as setResizeMode() or setMenuBar(). See the layout
overview page for more information.
To make your own layout manager, make a subclass of
QGLayoutIterator and implement the functions addItem(),
sizeHint(), setGeometry() and iterator(). You should also
implement minimumSize(), otherwise your layout will be
resized to zero size if there is little space. To support
children whose height depend on their widths, implement
hasHeightForWidth() and heightForWidth(). See the custom
layout page for an in-depth description.
Geometry management stops when the layout manager is
deleted.
Member Type Documentation
QLayout::ResizeMode
The possible values are are:
Fixed - the main widget's size is set to sizeHint(), it
cannot be resized at all.
Minimum - The main widget's minimum size is set to
minimumSize(), it cannot be smaller.
FreeResize - the widget is not constrained.
MEMBER FUNCTION DOCUMENTATIONQLayout::QLayout ( QWidget * parent, int border=0, int space=-1,
const char * name=0 )
Constructs a new top-level QLayout with main widget
parent. parent may not be 0.
border is the number of pixels between the edge of the
widget and the managed children. space sets the value of
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QLayout(3qt)QLayout(3qt)spacing(), which gives the spacing between widgets. The
default value for space is -1, which means that the value
of border is used.
name is the internal object name
There can only be one top-level layout for a widget. It is
returned by QWidget::layout().
QLayout::QLayout ( QLayout * parentLayout, int space=-1, const
char * name=0 )
Constructs a new child QLayout, and places it inside
parentLayout, using the default placement defined by
addItem().
If space is -1, this QLayout inherits parentLayout's
spacing(), otherwise space is used.
QLayout::QLayout ( int space=-1, const char * name=0 )
Constructs a new child QLayout, If space is -1, this
QLayout inherits its parent's spacing(), otherwise space
is used.
This layout has to be inserted into another layout before
geometry management will work.
QLayout::~QLayout ()
Destructs the layout, deleting all child layouts. Geometry
management stops when a toplevel layout is deleted.
bool QLayout::activate ()
Redoes the layout for mainWidget(). You should generally
not need to call this, as it is automatically called at
most appropriate times.
However, if you set up a QLayout for a visible widget
without resizing that widget, you need to call this
function in order to lay it out.
See also QWidget::updateGeometry().
Examples: layout/layout.cpp popup/popup.cpp
scrollview/scrollview.cpp
void QLayout::add ( QWidget * w )
Adds w to this layout in a manner specific to the layout.
This function uses addItem.
Examples: customlayout/main.cpp
void QLayout::addChildLayout ( QLayout * l ) [protected]
This function is called from addLayout functions in
subclasses, to add l layout as a sublayout.
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QLayout(3qt)QLayout(3qt)void QLayout::addItem ( QLayoutItem * item ) [virtual]
Implemented in subclasses to add item. How it is added is
specific to each subclass.
Note that the ownership of item is transferred to the
layout, and it is the layout's responsibility to delete
it.
Reimplemented in QGridLayout and QBoxLayout.
QRect QLayout::alignmentRect ( const QRect & r ) const
[protected]
Returns the rectangle that should be covered when the
geometry of this layout is set to r, if this layout
supports setAlignment().
The result is calculated from sizeHint() and expanding().
It is never larger than r.
bool QLayout::autoAdd () const
Returns TRUE if this layout automatically grabs all new
mainWidget()'s new children and adds them as defined by
addItem(). This only has effect for top-level layouts, ie.
layouts that are direct children of their mainWidget().
autoAdd() is disabled by default.
See also setAutoAdd().
void QLayout::deleteAllItems () [protected]
Removes and deletes all items in this layout.
bool QLayout::eventFilter ( QObject * o, QEvent * e ) [virtual
protected]
Performs child widget layout when the parent widget is
resized. Also handles removal of widgets and child
layouts.
Reimplemented from QObject.
QSizePolicy::ExpandData QLayout::expanding() const [virtual]
Returns whether this layout can make use of more space
than sizeHint(). A value of Vertical or Horizontal means
that it wants to grow in only one dimension, while
BothDirections means that it wants to grow in both
dimensions.
The default implementation returns BothDirections.
Reimplemented from QLayoutItem.
QRect QLayout::geometry () const [virtual]
Reimplemented for internal reasons; the API is not
affected.
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QLayout(3qt)QLayout(3qt)
Reimplemented from QLayoutItem.
void QLayout::invalidate () [virtual]
Invalidates cached information. Reimplementations must
call this.
Reimplemented from QLayoutItem.
bool QLayout::isEmpty () const [virtual]
Returns TRUE if this layout is empty. The default
implementation returns FALSE.
Reimplemented from QLayoutItem.
bool QLayout::isEnabled () const
Returns whether or not this layout is enabled.
See also setEnabled().
bool QLayout::isTopLevel () const
Returns TRUE if this layout is a top level layout, i.e.
not a child of another layout.
QLayoutIterator QLayout::iterator () [virtual]
Returns an iterator over the children of this layout.
This function must be implemented by subclasses.
Reimplemented from QLayoutItem.
QLayout * QLayout::layout () [virtual]
Reimplemented for internal reasons; the API is not
affected.
Reimplemented from QLayoutItem.
QWidget * QLayout::mainWidget ()
Returns the main widget (parent widget) of this layout, or
0 if this layout is a sub-layout which is not yet
inserted.
int QLayout::margin () const
returns the width of the outside border of the layout.
See also spacing() and setMargin().
QSize QLayout::maximumSize () const [virtual]
Returns the maximum size of this layout. This is the
largest size that the layout can have, while still
respecting the specifications. Does not include what's
needed by margin() or menuBar().
The default implementation allows unlimited resizing.
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QLayout(3qt)QLayout(3qt)
Reimplemented from QLayoutItem.
QMenuBar* QLayout::menuBar () const
Returns the menu bar set for this layout, or a null
pointer if no menu bar is set.
QSize QLayout::minimumSize () const [virtual]
Returns the minimum size of this layout. This is the
smallest size that the layout can have, while still
respecting the specifications. Does not include what's
needed by margin() or menuBar().
The default implementation allows unlimited resizing.
Reimplemented from QLayoutItem.
QLayout::ResizeMode QLayout::resizeMode() const
Returns the resize mode.
void QLayout::setAutoAdd ( bool b ) [virtual]
Sets autoAdd() if b is TRUE.
See also autoAdd().
Examples: i18n/main.cpp
void QLayout::setEnabled ( bool enable )
Enables this layout if enable is TRUE, otherwise disables
it.
An enabled layout adjusts dynamically to changes, a
disabled layout acts as if it was not existing.
By default, all layouts are enabled.
See also isEnabled().
void QLayout::setGeometry ( const QRect & r ) [virtual]
This function is reimplemented in subclasses to perform
layout.
The default implementation maintains the geometry()
information. Reimplementors must call this function.
Reimplemented from QLayoutItem.
void QLayout::setMargin ( int border ) [virtual]
Sets the outside border of the layout to border.
For some layout classes, this function only has an effect
on top-level layouts; QBoxLayout and QGridLayout support
margins for child layouts.
For some layout classes, this function only has an effect
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QLayout(3qt)QLayout(3qt)
on top-level layouts; QBoxLayout and QGridLayout support
margins for child layouts.
See also margin(), setSpacing() and supportsMargin().
void QLayout::setMenuBar ( QMenuBar * w ) [virtual]
Makes the geometry manager take account of the menu bar w.
All child widgets are placed below the bottom edge of the
menu bar.
A menu bar does its own geometry managing, never do
addWidget() on a QMenuBar.
Examples: scrollview/scrollview.cpp
void QLayout::setResizeMode ( ResizeMode mode )
Sets the resize mode to mode.
The default mode is Minimum for top level widgets, and
FreeResize for all others.
See also QLayout::ResizeMode.
void QLayout::setSpacing ( int space ) [virtual]
Sets the internal spacing of the layout to space.
See also spacing() and setMargin().
void QLayout::setSupportsMargin ( bool b ) [protected]
Sets the value returned by supportsMargin(). If b is TRUE,
margin() handling is implemented by the subclass. If b is
FALSE (the default) QLayout will add margin() around top-
level layouts.
If b is TRUE, margin handling needs to be implemented in
setGeometry(), maximumSize(), minimumSize(), sizeHint()
and heightForWidth().
See also supportsMargin().
int QLayout::spacing () const
Returns the spacing between widgets inside the layout.
See also margin() and setSpacing().
bool QLayout::supportsMargin () const
Returns TRUE if this layout supports setMargin() on non-
toplevel layouts.
See also setMargin().
int QLayout::totalHeightForWidth ( int w ) const
For internal use only.
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QLayout(3qt)QLayout(3qt)QSize QLayout::totalMaximumSize () const
For internal use only.
QSize QLayout::totalMinimumSize () const
For internal use only.
QSize QLayout::totalSizeHint () const
For internal use only.
SEE ALSO
http://doc.trolltech.com/qlayout.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2001 Trolltech AS,
http://www.trolltech.com. See the license file included
in the distribution for a complete license statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports
make our job much simpler. Thank you.
In case of content or formattting problems with this
manual page, please report them to qt-bugs@trolltech.com.
Please include the name of the manual page (qlayout.3qt)
and the Qt version (2.3.1).
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