The QLayoutItem class provides an abstract item that a QLayout manipulates. Más...

#include <qlayout.h>

Diagrama de herencias de QLayoutItem

Métodos públicos
	QLayoutItem (int alignment=0)
virtual	~QLayoutItem ()
virtual QSize	sizeHint () const =0
virtual QSize	minimumSize () const =0
virtual QSize	maximumSize () const =0
virtual QSizePolicy::ExpandData	expanding () const =0
virtual void	setGeometry (const QRect &)=0
virtual QRect	geometry () const =0
virtual bool	isEmpty () const =0
virtual bool	hasHeightForWidth () const
virtual int	heightForWidth (int) const
virtual void	invalidate ()
virtual QWidget *	widget ()
virtual QLayoutIterator	iterator ()
virtual QLayout *	layout ()
virtual QSpacerItem *	spacerItem ()
int	alignment () const
virtual void	setAlignment (int a)
	QLayoutItem (int alignment=0)
virtual	~QLayoutItem ()
virtual QSize	sizeHint () const =0
virtual QSize	minimumSize () const =0
virtual QSize	maximumSize () const =0
virtual QSizePolicy::ExpandData	expanding () const =0
virtual void	setGeometry (const QRect &)=0
virtual QRect	geometry () const =0
virtual bool	isEmpty () const =0
virtual bool	hasHeightForWidth () const
virtual int	heightForWidth (int) const
virtual void	invalidate ()
virtual QWidget *	widget ()
virtual QLayoutIterator	iterator ()
virtual QLayout *	layout ()
virtual QSpacerItem *	spacerItem ()
int	alignment () const
virtual void	setAlignment (int a)
Atributos protegidos
int	align

Descripción detallada

The QLayoutItem class provides an abstract item that a QLayout manipulates.

This is used by custom layouts.

Pure virtual functions are provided to return information about the layout, including, sizeHint(), minimumSize(), maximumSize() and expanding().

The layout's geometry can be set and retrieved with setGeometry() and geometry(), and its alignment with setAlignment() and alignment().

isEmpty() returns whether the layout is empty. iterator() returns an iterator for the layout's children. If the concrete item is a QWidget, it can be retrieved using widget(). Similarly for layout() and spacerItem().

Ver también:: QLayout

Documentación del constructor y destructor

QLayoutItem::QLayoutItem ( int alignment = 0 ) [inline]

Constructs a layout item with an alignment that is a bitwise OR of the {Qt::AlignmentFlags}. Not all subclasses support alignment.

QLayoutItem::~QLayoutItem ( ) [virtual]

Destroys the QLayoutItem.

QLayoutItem::QLayoutItem ( int alignment = 0 ) [inline]

virtual QLayoutItem::~QLayoutItem ( ) [virtual]

Documentación de las funciones miembro

int QLayoutItem::alignment ( ) const [inline]

Returns the alignment of this item.

int QLayoutItem::alignment ( ) const [inline]

virtual QSizePolicy::ExpandData QLayoutItem::expanding ( ) const [pure virtual]

Implementado en QTextTableCell, QDockAreaLayout, QSpacerItem, QWidgetItem, QLayout, QGridLayout, QBoxLayout, QSpacerItem, QWidgetItem, QLayout, QGridLayout, QBoxLayout, QTextTableCell, QDockAreaLayout, QDockWindowGridLayout, QMainWindowLayout y QwtDynGridLayout.

QSizePolicy::ExpandData QLayoutItem::expanding ( ) const [pure virtual]

Implemented in subclasses to return the direction(s) this item "wants" to expand in (if any).

Implementado en QTextTableCell, QDockAreaLayout, QSpacerItem, QWidgetItem, QLayout, QGridLayout, QBoxLayout, QSpacerItem, QWidgetItem, QLayout, QGridLayout, QBoxLayout, QTextTableCell, QDockAreaLayout, QDockWindowGridLayout, QMainWindowLayout y QwtDynGridLayout.

virtual QRect QLayoutItem::geometry ( ) const [pure virtual]

Implementado en QTextTableCell, QSpacerItem, QWidgetItem, QLayout, QSpacerItem, QWidgetItem, QLayout y QTextTableCell.

QRect QLayoutItem::geometry ( ) const [pure virtual]

Returns the rectangle covered by this layout item.

Implementado en QTextTableCell, QSpacerItem, QWidgetItem, QLayout, QSpacerItem, QWidgetItem, QLayout y QTextTableCell.

bool QLayoutItem::hasHeightForWidth ( ) const [virtual]

Returns TRUE if this layout's preferred height depends on its width; otherwise returns FALSE. The default implementation returns FALSE.

Reimplement this function in layout managers that support height for width.

Ver también:: heightForWidth(), QWidget::heightForWidth()

Reimplementado en QTextTableCell, QDockAreaLayout, QWidgetItem, QGridLayout, QBoxLayout, QWidgetItem, QGridLayout, QBoxLayout, QTextTableCell, QDockAreaLayout, QMainWindowLayout y QwtDynGridLayout.

virtual bool QLayoutItem::hasHeightForWidth ( ) const [virtual]

Reimplementado en QTextTableCell, QDockAreaLayout, QWidgetItem, QGridLayout, QBoxLayout, QWidgetItem, QGridLayout, QBoxLayout, QTextTableCell, QDockAreaLayout, QMainWindowLayout y QwtDynGridLayout.

int QLayoutItem::heightForWidth ( int ) const [virtual]

Returns the preferred height for this layout item, given the width w.

The default implementation returns -1, indicating that the preferred height is independent of the width of the item. Using the function hasHeightForWidth() will typically be much faster than calling this function and testing for -1.

Reimplement this function in layout managers that support height for width. A typical implementation will look like this:

        int MyLayout::heightForWidth( int w ) const
        {
            if ( cache_dirty || cached_width != w ) {
                // not all C++ compilers support "mutable"
                MyLayout *that = (MyLayout*)this;
                int h = calculateHeightForWidth( w );
                that->cached_hfw = h;
                return h;
            }
            return cached_hfw;
        }

Caching is strongly recommended; without it layout will take exponential time.