Qt 4.8: QGraphicsGridLayout Class Reference

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# QGraphicsGridLayout Class Reference

The QGraphicsGridLayout class provides a grid layout for managing widgets in Graphics View. More...

     #include <QGraphicsGridLayout>

Inherits: QGraphicsLayout.

This class was introduced in Qt 4.4.

- List of all members, including inherited members

## Public Functions

| QGraphicsGridLayout ( QGraphicsLayoutItem * parent = 0 )
virtual | ~QGraphicsGridLayout ()
void | addItem ( QGraphicsLayoutItem * item, int row, int column, int rowSpan, int columnSpan, Qt::Alignment alignment = 0 )
void | addItem ( QGraphicsLayoutItem * item, int row, int column, Qt::Alignment alignment = 0 )
Qt::Alignment | alignment ( QGraphicsLayoutItem * item ) const
Qt::Alignment | columnAlignment ( int column ) const
int | columnCount () const
qreal | columnMaximumWidth ( int column ) const
qreal | columnMinimumWidth ( int column ) const
qreal | columnPreferredWidth ( int column ) const
qreal | columnSpacing ( int column ) const
int | columnStretchFactor ( int column ) const
qreal | horizontalSpacing () const
QGraphicsLayoutItem * | itemAt ( int row, int column ) const
void | removeItem ( QGraphicsLayoutItem * item )
Qt::Alignment | rowAlignment ( int row ) const
int | rowCount () const
qreal | rowMaximumHeight ( int row ) const
qreal | rowMinimumHeight ( int row ) const
qreal | rowPreferredHeight ( int row ) const
qreal | rowSpacing ( int row ) const
int | rowStretchFactor ( int row ) const
void | setAlignment ( QGraphicsLayoutItem * item, Qt::Alignment alignment )
void | setColumnAlignment ( int column, Qt::Alignment alignment )
void | setColumnFixedWidth ( int column, qreal width )
void | setColumnMaximumWidth ( int column, qreal width )
void | setColumnMinimumWidth ( int column, qreal width )
void | setColumnPreferredWidth ( int column, qreal width )
void | setColumnSpacing ( int column, qreal spacing )
void | setColumnStretchFactor ( int column, int stretch )
void | setHorizontalSpacing ( qreal spacing )
void | setRowAlignment ( int row, Qt::Alignment alignment )
void | setRowFixedHeight ( int row, qreal height )
void | setRowMaximumHeight ( int row, qreal height )
void | setRowMinimumHeight ( int row, qreal height )
void | setRowPreferredHeight ( int row, qreal height )
void | setRowSpacing ( int row, qreal spacing )
void | setRowStretchFactor ( int row, int stretch )
void | setSpacing ( qreal spacing )
void | setVerticalSpacing ( qreal spacing )
qreal | verticalSpacing () const

## Reimplemented Public Functions

virtual int | count () const
virtual void | invalidate ()
virtual QGraphicsLayoutItem * | itemAt ( int index ) const
virtual void | removeAt ( int index )
virtual void | setGeometry ( const QRectF & rect )
virtual QSizeF | sizeHint ( Qt::SizeHint which, const QSizeF & constraint = QSizeF() ) const

- 10 public functions inherited from QGraphicsLayout
- 35 public functions inherited from QGraphicsLayoutItem

### Additional Inherited Members

- 2 static public members inherited from QGraphicsLayout
- 1 protected function inherited from QGraphicsLayout
- 3 protected functions inherited from QGraphicsLayoutItem

## Detailed Description

The QGraphicsGridLayout class provides a grid layout for managing widgets in Graphics View.

The most common way to use QGraphicsGridLayout is to construct an object on the heap with no parent, add widgets and layouts by calling addItem(), and finally assign the layout to a widget by calling QGraphicsWidget::setLayout(). QGraphicsGridLayout automatically computes the dimensions of the grid as you add items.

     QGraphicsScene scene;
     QGraphicsWidget *textEdit = scene.addWidget(new QTextEdit);
     QGraphicsWidget *pushButton = scene.addWidget(new QPushButton);

     QGraphicsGridLayout *layout = new QGraphicsGridLayout;
     layout->addItem(textEdit, 0, 0);
     layout->addItem(pushButton, 0, 1);

     QGraphicsWidget *form = new QGraphicsWidget;
     form->setLayout(layout);
     scene.addItem(form);

The layout takes ownership of the items. In some cases when the layout item also inherits from QGraphicsItem (such as QGraphicsWidget) there will be a ambiguity in ownership because the layout item belongs to two ownership hierarchies. See the documentation of QGraphicsLayoutItem::setOwnedByLayout() how to handle this. You can access each item in the layout by calling count() and itemAt(). Calling removeAt() will remove an item from the layout, without destroying it.

### Size Hints and Size Policies in QGraphicsGridLayout

QGraphicsGridLayout respects each item's size hints and size policies, and when a cell in the grid has more space than the items can fill, each item is arranged according to the layout's alignment for that item. You can set an alignment for each item by calling setAlignment(), and check the alignment for any item by calling alignment(). You can also set the alignment for an entire row or column by calling setRowAlignment() and setColumnAlignment() respectively. By default, items are aligned to the top left.

See also QGraphicsLinearLayout and QGraphicsWidget.

## Member Function Documentation

### QGraphicsGridLayout::QGraphicsGridLayout ( QGraphicsLayoutItem * parent = 0 )

Constructs a QGraphicsGridLayout instance. parent is passed to QGraphicsLayout's constructor.

### QGraphicsGridLayout::~QGraphicsGridLayout ()`[virtual]`

Destroys the QGraphicsGridLayout object.

### void QGraphicsGridLayout::addItem ( QGraphicsLayoutItem * item, int row, int column, int rowSpan, int columnSpan, Qt::Alignment alignment = 0 )

Adds item to the grid on row and column. You can specify a rowSpan and columnSpan and an optional alignment.

### void QGraphicsGridLayout::addItem ( QGraphicsLayoutItem * item, int row, int column, Qt::Alignment alignment = 0 )

Adds item to the grid on row and column. You can specify an optional alignment for item.

### Qt::Alignment QGraphicsGridLayout::alignment ( QGraphicsLayoutItem * item ) const

Returns the alignment for item.

See also setAlignment().

### Qt::Alignment QGraphicsGridLayout::columnAlignment ( int column ) const

Returns the alignment for column.

See also setColumnAlignment().

### int QGraphicsGridLayout::columnCount () const

Returns the number of columns in the grid layout. This is always one more than the index of the last column that is occupied by a layout item (empty columns are counted except for those at the end).

### qreal QGraphicsGridLayout::columnMaximumWidth ( int column ) const

Returns the maximum width for column.

See also setColumnMaximumWidth().

### qreal QGraphicsGridLayout::columnMinimumWidth ( int column ) const

Returns the minimum width for column.

See also setColumnMinimumWidth().

### qreal QGraphicsGridLayout::columnPreferredWidth ( int column ) const

Returns the preferred width for column.

See also setColumnPreferredWidth().

### qreal QGraphicsGridLayout::columnSpacing ( int column ) const

Returns the column spacing for column.

See also setColumnSpacing().

### int QGraphicsGridLayout::columnStretchFactor ( int column ) const

Returns the stretch factor for column.

See also setColumnStretchFactor().

### int QGraphicsGridLayout::count () const`[virtual]`

Reimplemented from QGraphicsLayout::count().

Returns the number of layout items in this grid layout.

### qreal QGraphicsGridLayout::horizontalSpacing () const

Returns the default horizontal spacing for the grid layout.

See also setHorizontalSpacing().

### void QGraphicsGridLayout::invalidate ()`[virtual]`

Reimplemented from QGraphicsLayout::invalidate().

### QGraphicsLayoutItem * QGraphicsGridLayout::itemAt ( int row, int column ) const

Returns a pointer to the layout item at (row, column).

### QGraphicsLayoutItem * QGraphicsGridLayout::itemAt ( int index ) const`[virtual]`

Reimplemented from QGraphicsLayout::itemAt().

Returns the layout item at index, or 0 if there is no layout item at this index.

### void QGraphicsGridLayout::removeAt ( int index )`[virtual]`

Reimplemented from QGraphicsLayout::removeAt().

Removes the layout item at index without destroying it. Ownership of the item is transferred to the caller.

See also addItem().

### void QGraphicsGridLayout::removeItem ( QGraphicsLayoutItem * item )

Removes the layout item item without destroying it. Ownership of the item is transferred to the caller.

This function was introduced in Qt 4.8.

See also addItem().

### Qt::Alignment QGraphicsGridLayout::rowAlignment ( int row ) const

Returns the alignment of row.

See also setRowAlignment().

### int QGraphicsGridLayout::rowCount () const

Returns the number of rows in the grid layout. This is always one more than the index of the last row that is occupied by a layout item (empty rows are counted except for those at the end).

### qreal QGraphicsGridLayout::rowMaximumHeight ( int row ) const

Returns the maximum height for row, row.

See also setRowMaximumHeight().

### qreal QGraphicsGridLayout::rowMinimumHeight ( int row ) const

Returns the minimum height for row, row.

See also setRowMinimumHeight().

### qreal QGraphicsGridLayout::rowPreferredHeight ( int row ) const

Returns the preferred height for row, row.

See also setRowPreferredHeight().

### qreal QGraphicsGridLayout::rowSpacing ( int row ) const

Returns the row spacing for row.

See also setRowSpacing().

### int QGraphicsGridLayout::rowStretchFactor ( int row ) const

Returns the stretch factor for row.

See also setRowStretchFactor().

### void QGraphicsGridLayout::setAlignment ( QGraphicsLayoutItem * item, Qt::Alignment alignment )

Sets the alignment for item to alignment.

See also alignment().

### void QGraphicsGridLayout::setColumnAlignment ( int column, Qt::Alignment alignment )

Sets the alignment for column to alignment.

See also columnAlignment().

### void QGraphicsGridLayout::setColumnFixedWidth ( int column, qreal width )

Sets the fixed width of column to width.

### void QGraphicsGridLayout::setColumnMaximumWidth ( int column, qreal width )

Sets the maximum width of column to width.

See also columnMaximumWidth().

### void QGraphicsGridLayout::setColumnMinimumWidth ( int column, qreal width )

Sets the minimum width for column to width.

See also columnMinimumWidth().

### void QGraphicsGridLayout::setColumnPreferredWidth ( int column, qreal width )

Sets the preferred width for column to width.

See also columnPreferredWidth().

### void QGraphicsGridLayout::setColumnSpacing ( int column, qreal spacing )

Sets the spacing for column to spacing.

See also columnSpacing().

### void QGraphicsGridLayout::setColumnStretchFactor ( int column, int stretch )

Sets the stretch factor for column to stretch.

See also columnStretchFactor().

### void QGraphicsGridLayout::setGeometry ( const QRectF & rect )`[virtual]`

Reimplemented from QGraphicsLayoutItem::setGeometry().

Sets the bounding geometry of the grid layout to rect.

### void QGraphicsGridLayout::setHorizontalSpacing ( qreal spacing )

Sets the default horizontal spacing for the grid layout to spacing.

See also horizontalSpacing().

### void QGraphicsGridLayout::setRowAlignment ( int row, Qt::Alignment alignment )

Sets the alignment of row to alignment.

See also rowAlignment().

### void QGraphicsGridLayout::setRowFixedHeight ( int row, qreal height )

Sets the fixed height for row, row, to height.

### void QGraphicsGridLayout::setRowMaximumHeight ( int row, qreal height )

Sets the maximum height for row, row, to height.

See also rowMaximumHeight().

### void QGraphicsGridLayout::setRowMinimumHeight ( int row, qreal height )

Sets the minimum height for row, row, to height.

See also rowMinimumHeight().

### void QGraphicsGridLayout::setRowPreferredHeight ( int row, qreal height )

Sets the preferred height for row, row, to height.

See also rowPreferredHeight().

### void QGraphicsGridLayout::setRowSpacing ( int row, qreal spacing )

Sets the spacing for row to spacing.

See also rowSpacing().

### void QGraphicsGridLayout::setRowStretchFactor ( int row, int stretch )

Sets the stretch factor for row to stretch.

See also rowStretchFactor().

### void QGraphicsGridLayout::setSpacing ( qreal spacing )

Sets the grid layout's default spacing, both vertical and horizontal, to spacing.

See also rowSpacing() and columnSpacing().

### void QGraphicsGridLayout::setVerticalSpacing ( qreal spacing )

Sets the default vertical spacing for the grid layout to spacing.

See also verticalSpacing().

### QSizeF QGraphicsGridLayout::sizeHint ( Qt::SizeHint which, const QSizeF & constraint = QSizeF() ) const`[virtual]`

Reimplemented from QGraphicsLayoutItem::sizeHint().

### qreal QGraphicsGridLayout::verticalSpacing () const

Returns the default vertical spacing for the grid layout.

See also setVerticalSpacing().