QHeaderView Class Reference

The QHeaderView class provides a header row or header column for item views. More...

 #include <QHeaderView>

Inherits: QAbstractItemView.

Public Types

enum ResizeMode { Interactive, Fixed, Stretch, ResizeToContents, Custom }

Properties

Public Functions

QHeaderView ( Qt::Orientation orientation, QWidget * parent = 0 )
virtual ~QHeaderView ()
bool cascadingSectionResizes () const
int count () const
Qt::Alignment defaultAlignment () const
int defaultSectionSize () const
int hiddenSectionCount () const
void hideSection ( int logicalIndex )
bool highlightSections () const
bool isClickable () const
bool isMovable () const
bool isSectionHidden ( int logicalIndex ) const
bool isSortIndicatorShown () const
int length () const
int logicalIndex ( int visualIndex ) const
int logicalIndexAt ( int position ) const
int logicalIndexAt ( int x, int y ) const
int logicalIndexAt ( const QPoint & pos ) const
int minimumSectionSize () const
void moveSection ( int from, int to )
int offset () const
Qt::Orientation orientation () const
ResizeMode resizeMode ( int logicalIndex ) const
void resizeSection ( int logicalIndex, int size )
void resizeSections ( QHeaderView::ResizeMode mode )
bool restoreState ( const QByteArray & state )
QByteArray saveState () const
int sectionPosition ( int logicalIndex ) const
int sectionSize ( int logicalIndex ) const
int sectionSizeHint ( int logicalIndex ) const
int sectionViewportPosition ( int logicalIndex ) const
bool sectionsHidden () const
bool sectionsMoved () const
void setCascadingSectionResizes ( bool enable )
void setClickable ( bool clickable )
void setDefaultAlignment ( Qt::Alignment alignment )
void setDefaultSectionSize ( int size )
void setHighlightSections ( bool highlight )
void setMinimumSectionSize ( int size )
void setMovable ( bool movable )
void setResizeMode ( ResizeMode mode )
void setResizeMode ( int logicalIndex, ResizeMode mode )
void setSectionHidden ( int logicalIndex, bool hide )
void setSortIndicator ( int logicalIndex, Qt::SortOrder order )
void setSortIndicatorShown ( bool show )
void setStretchLastSection ( bool stretch )
void showSection ( int logicalIndex )
Qt::SortOrder sortIndicatorOrder () const
int sortIndicatorSection () const
bool stretchLastSection () const
int stretchSectionCount () const
void swapSections ( int first, int second )
int visualIndex ( int logicalIndex ) const
int visualIndexAt ( int position ) const

Reimplemented Public Functions

virtual void reset ()
virtual void setModel ( QAbstractItemModel * model )
virtual QSize sizeHint () const

Public Slots

void headerDataChanged ( Qt::Orientation orientation, int logicalFirst, int logicalLast )
void setOffset ( int offset )
void setOffsetToLastSection ()
void setOffsetToSectionPosition ( int visualIndex )

Signals

void geometriesChanged ()
void sectionAutoResize ( int logicalIndex, QHeaderView::ResizeMode mode )
void sectionClicked ( int logicalIndex )
void sectionCountChanged ( int oldCount, int newCount )
void sectionDoubleClicked ( int logicalIndex )
void sectionEntered ( int logicalIndex )
void sectionHandleDoubleClicked ( int logicalIndex )
void sectionMoved ( int logicalIndex, int oldVisualIndex, int newVisualIndex )
void sectionPressed ( int logicalIndex )
void sectionResized ( int logicalIndex, int oldSize, int newSize )
void sortIndicatorChanged ( int logicalIndex, Qt::SortOrder order )

Protected Functions

void initStyleOption ( QStyleOptionHeader * option ) const
virtual void paintSection ( QPainter * painter, const QRect & rect, int logicalIndex ) const
virtual QSize sectionSizeFromContents ( int logicalIndex ) const

Reimplemented Protected Functions

virtual void currentChanged ( const QModelIndex & current, const QModelIndex & old )
virtual bool event ( QEvent * e )
virtual int horizontalOffset () const
virtual void mouseDoubleClickEvent ( QMouseEvent * e )
virtual void mouseMoveEvent ( QMouseEvent * e )
virtual void mousePressEvent ( QMouseEvent * e )
virtual void mouseReleaseEvent ( QMouseEvent * e )
virtual void paintEvent ( QPaintEvent * e )
virtual void setSelection ( const QRect & rect, QItemSelectionModel::SelectionFlags flags )
virtual int verticalOffset () const
virtual bool viewportEvent ( QEvent * e )

Protected Slots

void resizeSections ()
void sectionsAboutToBeRemoved ( const QModelIndex & parent, int logicalFirst, int logicalLast )
void sectionsInserted ( const QModelIndex & parent, int logicalFirst, int logicalLast )

Additional Inherited Members

  • 4 static public members inherited from QWidget
  • 7 static public members inherited from QObject

Detailed Description

The QHeaderView class provides a header row or header column for item views.

A QHeaderView displays the headers used in item views such as the QTableView and QTreeView classes. It takes the place of Qt3's QHeader class previously used for the same purpose, but uses the Qt's model/view architecture for consistency with the item view classes.

The QHeaderView class is one of the Model/View Classes and is part of Qt's model/view framework.

The header gets the data for each section from the model using the QAbstractItemModel::headerData() function. You can set the data by using QAbstractItemModel::setHeaderData().

Each header has an orientation() and a number of sections, given by the count() function. A section refers to a part of the header - either a row or a column, depending on the orientation.

Sections can be moved and resized using moveSection() and resizeSection(); they can also be hidden and shown with hideSection() and showSection().

Each section of a header is described by a section ID, specified by its section(), and can be located at a particular visualIndex() in the header. A section can have a sort indicator set with setSortIndicator(); this indicates whether the items in the associated item view will be sorted in the order given by the section.

For a horizontal header the section is equivalent to a column in the model, and for a vertical header the section is equivalent to a row in the model.

Moving Header Sections

A header can be fixed in place, or made movable with setMovable(). It can be made clickable with setClickable(), and has resizing behavior in accordance with setResizeMode().

Note: Double-clicking on a header to resize a section only applies for visible rows.

A header will emit sectionMoved() if the user moves a section, sectionResized() if the user resizes a section, and sectionClicked() as well as sectionHandleDoubleClicked() in response to mouse clicks. A header will also emit sectionCountChanged() and sectionAutoResize().

You can identify a section using the logicalIndex() and logicalIndexAt() functions, or by its index position, using the visualIndex() and visualIndexAt() functions. The visual index will change if a section is moved, but the logical index will not change.

Appearance

QTableWidget and QTableView create default headers. If you want the headers to be visible, you can use setVisible().

Not all ItemDataRoles will have an effect on a QHeaderView. If you need to draw other roles, you can subclass QHeaderView and reimplement paintEvent(). QHeaderView respects the following item data roles: TextAlignmentRole, DisplayRole, FontRole, DecorationRole, ForegroundRole, and BackgroundRole.

Note: Each header renders the data for each section itself, and does not rely on a delegate. As a result, calling a header's setItemDelegate() function will have no effect.

See also Model/View Programming, QListView, QTableView, and QTreeView.

Member Type Documentation

enum QHeaderView::ResizeMode

The resize mode specifies the behavior of the header sections. It can be set on the entire header view or on individual sections using setResizeMode().

ConstantValueDescription
QHeaderView::Interactive0The user can resize the section. The section can also be resized programmatically using resizeSection(). The section size defaults to defaultSectionSize. (See also cascadingSectionResizes.)
QHeaderView::Fixed2The user cannot resize the section. The section can only be resized programmatically using resizeSection(). The section size defaults to defaultSectionSize.
QHeaderView::Stretch1QHeaderView will automatically resize the section to fill the available space. The size cannot be changed by the user or programmatically.
QHeaderView::ResizeToContents3QHeaderView will automatically resize the section to its optimal size based on the contents of the entire column or row. The size cannot be changed by the user or programmatically. (This value was introduced in 4.2)

The following values are obsolete:

ConstantValueDescription
QHeaderView::CustomFixedUse Fixed instead.

See also setResizeMode(), stretchLastSection, and minimumSectionSize.

Property Documentation

cascadingSectionResizes : bool

This property holds whether interactive resizing will be cascaded to the following sections once the section being resized by the user has reached its minimum size.

This property only affects sections that have Interactive as their resize mode.

The default value is false.

This property was introduced in Qt 4.2.

Access functions:

bool cascadingSectionResizes () const
void setCascadingSectionResizes ( bool enable )

See also setResizeMode().

defaultAlignment : Qt::Alignment

This property holds the default alignment of the text in each header section.

This property was introduced in Qt 4.1.

Access functions:

Qt::Alignment defaultAlignment () const
void setDefaultAlignment ( Qt::Alignment alignment )

defaultSectionSize : int

This property holds the default size of the header sections before resizing.

This property only affects sections that have Interactive or Fixed as their resize mode.

Access functions:

int defaultSectionSize () const
void setDefaultSectionSize ( int size )

See also setResizeMode() and minimumSectionSize.

highlightSections : bool

This property holds whether the sections containing selected items are highlighted.

By default, this property is false.

Access functions:

bool highlightSections () const
void setHighlightSections ( bool highlight )

minimumSectionSize : int

This property holds the minimum size of the header sections.

The minimum section size is the smallest section size allowed. If the minimum section size is set to -1, QHeaderView will use the maximum of the global strut or the font metrics size.

This property is honored by all resize modes.

This property was introduced in Qt 4.2.

Access functions:

int minimumSectionSize () const
void setMinimumSectionSize ( int size )

See also setResizeMode() and defaultSectionSize.

showSortIndicator : bool

This property holds whether the sort indicator is shown.

By default, this property is false.

Access functions:

bool isSortIndicatorShown () const
void setSortIndicatorShown ( bool show )

See also setClickable().

stretchLastSection : bool

This property holds whether the last visible section in the header takes up all the available space.

The default value is false.

Note: The horizontal headers provided by QTreeView are configured with this property set to true, ensuring that the view does not waste any of the space assigned to it for its header. If this value is set to true, this property will override the resize mode set on the last section in the header.

Access functions:

bool stretchLastSection () const
void setStretchLastSection ( bool stretch )

See also setResizeMode().

Member Function Documentation

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

Creates a new generic header with the given orientation and parent.

QHeaderView::~QHeaderView () [virtual]

Destroys the header.

int QHeaderView::count () const

Returns the number of sections in the header.

See also sectionCountChanged() and length().

void QHeaderView::currentChanged ( const QModelIndex & current, const QModelIndex & old ) [virtual protected]

Reimplemented from QAbstractItemView::currentChanged().

bool QHeaderView::event ( QEvent * e ) [virtual protected]

Reimplemented from QObject::event().

void QHeaderView::geometriesChanged () [signal]

This signal is emitted when the header's geometries have changed.

This function was introduced in Qt 4.2.

void QHeaderView::headerDataChanged ( Qt::Orientation orientation, int logicalFirst, int logicalLast ) [slot]

Updates the changed header sections with the given orientation, from logicalFirst to logicalLast inclusive.

int QHeaderView::hiddenSectionCount () const

Returns the number of sections in the header that has been hidden.

This function was introduced in Qt 4.1.

See also setSectionHidden() and isSectionHidden().

void QHeaderView::hideSection ( int logicalIndex )

Hides the section specified by logicalIndex.

See also showSection(), isSectionHidden(), hiddenSectionCount(), and setSectionHidden().

int QHeaderView::horizontalOffset () const [virtual protected]

Reimplemented from QAbstractItemView::horizontalOffset().

Returns the horizontal offset of the header. This is 0 for vertical headers.

See also offset().

void QHeaderView::initStyleOption ( QStyleOptionHeader * option ) const [protected]

Initialize option with the values from this QHeaderView. This method is useful for subclasses when they need a QStyleOptionHeader, but do not want to fill in all the information themselves.

See also QStyleOption::initFrom().

bool QHeaderView::isClickable () const

Returns true if the header is clickable; otherwise returns false. A clickable header could be set up to allow the user to change the representation of the data in the view related to the header.

See also setClickable().

bool QHeaderView::isMovable () const

Returns true if the header can be moved by the user; otherwise returns false.

See also setMovable().

bool QHeaderView::isSectionHidden ( int logicalIndex ) const

Returns true if the section specified by logicalIndex is explicitly hidden from the user; otherwise returns false.

See also hideSection(), showSection(), setSectionHidden(), and hiddenSectionCount().

int QHeaderView::length () const

Returns the length along the orientation of the header.

See also sizeHint(), setResizeMode(), and offset().

int QHeaderView::logicalIndex ( int visualIndex ) const

Returns the logicalIndex for the section at the given visualIndex position, or -1 if visualIndex < 0 or visualIndex >= QHeaderView::count().

Note that the visualIndex is not affected by hidden sections.

See also visualIndex() and sectionPosition().

int QHeaderView::logicalIndexAt ( int position ) const

Returns the section that covers the given position in the viewport.

See also visualIndexAt() and isSectionHidden().

int QHeaderView::logicalIndexAt ( int x, int y ) const

Returns the logical index of the section at the given coordinate. If the header is horizontal x will be used, otherwise y will be used to find the logical index.

int QHeaderView::logicalIndexAt ( const QPoint & pos ) const

Returns the logical index of the section at the position given in pos. If the header is horizontal the x-coordinate will be used, otherwise the y-coordinate will be used to find the logical index.

See also sectionPosition().

void QHeaderView::mouseDoubleClickEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mouseDoubleClickEvent().

void QHeaderView::mouseMoveEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mouseMoveEvent().

void QHeaderView::mousePressEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mousePressEvent().

void QHeaderView::mouseReleaseEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mouseReleaseEvent().

void QHeaderView::moveSection ( int from, int to )

Moves the section at visual index from to occupy visual index to.

See also sectionsMoved().

int QHeaderView::offset () const

Returns the offset of the header: this is the header's left-most (or top-most for vertical headers) visible pixel.

See also setOffset().

Qt::Orientation QHeaderView::orientation () const

Returns the orientation of the header.

See also Qt::Orientation.

void QHeaderView::paintEvent ( QPaintEvent * e ) [virtual protected]

Reimplemented from QWidget::paintEvent().

void QHeaderView::paintSection ( QPainter * painter, const QRect & rect, int logicalIndex ) const [virtual protected]

Paints the section specified by the given logicalIndex, using the given painter and rect.

Normally, you do not have to call this function.

void QHeaderView::reset () [virtual]

Reimplemented from QAbstractItemView::reset().

ResizeMode QHeaderView::resizeMode ( int logicalIndex ) const

Returns the resize mode that applies to the section specified by the given logicalIndex.

See also setResizeMode().

void QHeaderView::resizeSection ( int logicalIndex, int size )

Resizes the section specified by logicalIndex to size measured in pixels.

See also sectionResized(), resizeMode(), and sectionSize().

void QHeaderView::resizeSections ( QHeaderView::ResizeMode mode )

Resizes the sections according to the given mode, ignoring the current resize mode.

See also resizeMode() and sectionResized().

void QHeaderView::resizeSections () [protected slot]

Resizes the sections according to their size hints. Normally, you do not have to call this function.

bool QHeaderView::restoreState ( const QByteArray & state )

Restores the state of this header view. This function returns true if the state was restored; otherwise returns false.

This function was introduced in Qt 4.3.

See also saveState().

QByteArray QHeaderView::saveState () const

Saves the current state of this header view.

To restore the saved state, pass the return value to restoreState().

This function was introduced in Qt 4.3.

See also restoreState().

void QHeaderView::sectionAutoResize ( int logicalIndex, QHeaderView::ResizeMode mode ) [signal]

This signal is emitted when a section is automatically resized. The section's logical index is specified by logicalIndex, and the resize mode by mode.

See also setResizeMode() and stretchLastSection().

void QHeaderView::sectionClicked ( int logicalIndex ) [signal]

This signal is emitted when a section is clicked. The section's logical index is specified by logicalIndex.

Note that the sectionPressed signal will also be emitted.

See also setClickable() and sectionPressed().

void QHeaderView::sectionCountChanged ( int oldCount, int newCount ) [signal]

This signal is emitted when the number of sections changes, i.e., when sections are added or deleted. The original count is specified by oldCount, and the new count by newCount.

See also count(), length(), and headerDataChanged().

void QHeaderView::sectionDoubleClicked ( int logicalIndex ) [signal]

This signal is emitted when a section is double-clicked. The section's logical index is specified by logicalIndex.

See also setClickable().

void QHeaderView::sectionEntered ( int logicalIndex ) [signal]

This signal is emitted when the cursor moves over the section and the left mouse button is pressed. The section's logical index is specified by logicalIndex.

This function was introduced in Qt 4.3.

See also setClickable() and sectionPressed().

void QHeaderView::sectionHandleDoubleClicked ( int logicalIndex ) [signal]

This signal is emitted when a section is double-clicked. The section's logical index is specified by logicalIndex.

See also setClickable().

void QHeaderView::sectionMoved ( int logicalIndex, int oldVisualIndex, int newVisualIndex ) [signal]

This signal is emitted when a section is moved. The section's logical index is specified by logicalIndex, the old index by oldVisualIndex, and the new index position by newVisualIndex.

See also moveSection().

int QHeaderView::sectionPosition ( int logicalIndex ) const

Returns the section position of the given logicalIndex, or -1 if the section is hidden. The position is measured in pixels from the first visible item's top-left corner to the top-left corner of the item with logicalIndex. The measurement is along the x-axis for horizontal headers and along the y-axis for vertical headers.

See also sectionViewportPosition().

void QHeaderView::sectionPressed ( int logicalIndex ) [signal]

This signal is emitted when a section is pressed. The section's logical index is specified by logicalIndex.

See also setClickable().

void QHeaderView::sectionResized ( int logicalIndex, int oldSize, int newSize ) [signal]

This signal is emitted when a section is resized. The section's logical number is specified by logicalIndex, the old size by oldSize, and the new size by newSize.

See also resizeSection().

int QHeaderView::sectionSize ( int logicalIndex ) const

Returns the width (or height for vertical headers) of the given logicalIndex.

See also length(), setResizeMode(), and defaultSectionSize().

QSize QHeaderView::sectionSizeFromContents ( int logicalIndex ) const [virtual protected]

Returns the size of the contents of the section specified by the given logicalIndex.

See also defaultSectionSize().

int QHeaderView::sectionSizeHint ( int logicalIndex ) const

Returns a suitable size hint for the section specified by logicalIndex.

See also sizeHint(), defaultSectionSize(), minimumSectionSize(), and Qt::SizeHintRole.

int QHeaderView::sectionViewportPosition ( int logicalIndex ) const

Returns the section viewport position of the given logicalIndex.

If the section is hidden, the return value is undefined.

See also sectionPosition() and isSectionHidden().

void QHeaderView::sectionsAboutToBeRemoved ( const QModelIndex & parent, int logicalFirst, int logicalLast ) [protected slot]

This slot is called when sections are removed from the parent. logicalFirst and logicalLast signify where the sections were removed.

If only one section is removed, logicalFirst and logicalLast will be the same.

bool QHeaderView::sectionsHidden () const

Returns true if sections in the header has been hidden; otherwise returns false;

This function was introduced in Qt 4.1.

See also setSectionHidden().

void QHeaderView::sectionsInserted ( const QModelIndex & parent, int logicalFirst, int logicalLast ) [protected slot]

This slot is called when sections are inserted into the parent. logicalFirst and logicalLast indices signify where the new sections were inserted.

If only one section is inserted, logicalFirst and logicalLast will be the same.

bool QHeaderView::sectionsMoved () const

Returns true if sections in the header has been moved; otherwise returns false;

See also moveSection().

void QHeaderView::setClickable ( bool clickable )

If clickable is true, the header will respond to single clicks.

See also isClickable(), sectionClicked(), sectionPressed(), and setSortIndicatorShown().

void QHeaderView::setModel ( QAbstractItemModel * model ) [virtual]

Reimplemented from QAbstractItemView::setModel().

void QHeaderView::setMovable ( bool movable )

If movable is true, the header may be moved by the user; otherwise it is fixed in place.

See also isMovable() and sectionMoved().

void QHeaderView::setOffset ( int offset ) [slot]

Sets the header's offset to offset.

See also offset() and length().

void QHeaderView::setOffsetToLastSection () [slot]

Sets the offset to make the last section visible.

This function was introduced in Qt 4.2.

See also setOffset(), sectionPosition(), and setOffsetToSectionPosition().

void QHeaderView::setOffsetToSectionPosition ( int visualIndex ) [slot]

Sets the offset to the start of the section at the given visualIndex.

This function was introduced in Qt 4.2.

See also setOffset() and sectionPosition().

void QHeaderView::setResizeMode ( ResizeMode mode )

Sets the constraints on how the header can be resized to those described by the given mode.

See also resizeMode(), length(), sectionResized(), and sectionAutoResize().

void QHeaderView::setResizeMode ( int logicalIndex, ResizeMode mode )

This is an overloaded function.

Sets the constraints on how the section specified by logicalIndex in the header can be resized to those described by the given mode. The logical index should exist at the time this function is called.

Note: This setting will be ignored for the last section if the stretchLastSection property is set to true. This is the default for the horizontal headers provided by QTreeView.

See also setStretchLastSection().

void QHeaderView::setSectionHidden ( int logicalIndex, bool hide )

If hide is true the section specified by logicalIndex is hidden; otherwise the section is shown.

See also isSectionHidden() and hiddenSectionCount().

void QHeaderView::setSelection ( const QRect & rect, QItemSelectionModel::SelectionFlags flags ) [virtual protected]

Reimplemented from QAbstractItemView::setSelection().

Selects the items in the given rect according to the specified flags.

The base class implementation does nothing.

void QHeaderView::setSortIndicator ( int logicalIndex, Qt::SortOrder order )

Sets the sort indicator for the section specified by the given logicalIndex in the direction specified by order, and removes the sort indicator from any other section that was showing it.

logicalIndex may be -1, in which case no sort indicator will be shown and the model will return to its natural, unsorted order. Note that not all models support this and may even crash in this case.

See also sortIndicatorSection() and sortIndicatorOrder().

void QHeaderView::showSection ( int logicalIndex )

Shows the section specified by logicalIndex.

See also hideSection(), isSectionHidden(), hiddenSectionCount(), and setSectionHidden().

QSize QHeaderView::sizeHint () const [virtual]

Reimplemented from QWidget::sizeHint().

Returns a suitable size hint for this header.

See also sectionSizeHint().

void QHeaderView::sortIndicatorChanged ( int logicalIndex, Qt::SortOrder order ) [signal]

This signal is emitted when the section containing the sort indicator or the order indicated is changed. The section's logical index is specified by logicalIndex and the sort order is specified by order.

This function was introduced in Qt 4.3.

See also setSortIndicator().

Qt::SortOrder QHeaderView::sortIndicatorOrder () const

Returns the order for the sort indicator. If no section has a sort indicator the return value of this function is undefined.

See also setSortIndicator() and sortIndicatorSection().

int QHeaderView::sortIndicatorSection () const

Returns the logical index of the section that has a sort indicator. By default this is section 0.

See also setSortIndicator(), sortIndicatorOrder(), and setSortIndicatorShown().

int QHeaderView::stretchSectionCount () const

Returns the number of sections that are set to resize mode stretch. In views, this can be used to see if the headerview needs to resize the sections when the view's geometry changes.

This function was introduced in Qt 4.1.

See also stretchLastSection and resizeMode().

void QHeaderView::swapSections ( int first, int second )

Swaps the section at visual index first with the section at visual index second.

This function was introduced in Qt 4.2.

See also moveSection().

int QHeaderView::verticalOffset () const [virtual protected]

Reimplemented from QAbstractItemView::verticalOffset().

Returns the vertical offset of the header. This is 0 for horizontal headers.

See also offset().

bool QHeaderView::viewportEvent ( QEvent * e ) [virtual protected]

Reimplemented from QAbstractScrollArea::viewportEvent().

int QHeaderView::visualIndex ( int logicalIndex ) const

Returns the visual index position of the section specified by the given logicalIndex, or -1 otherwise.

Hidden sections still have valid visual indexes.

See also logicalIndex().

int QHeaderView::visualIndexAt ( int position ) const

Returns the visual index of the section that covers the given position in the viewport.

See also logicalIndexAt().

Notes provided by the Qt Community

No notes