QTabBar Class

The QTabBar class provides a tab bar, e.g. for use in tabbed dialogs. More...

Header:	#include <QTabBar>
qmake:	QT += widgets
Inherits:	QWidget

• List of all members, including inherited members

Public Types

enum	ButtonPosition { LeftSide, RightSide }
enum	SelectionBehavior { SelectLeftTab, SelectRightTab, SelectPreviousTab }
enum	Shape { RoundedNorth, RoundedSouth, RoundedWest, RoundedEast, TriangularNorth, …, TriangularEast }

Properties

autoHide : bool changeCurrentOnDrag : bool count : const int currentIndex : int documentMode : bool drawBase : bool elideMode : Qt::TextElideMode

expanding : bool iconSize : QSize movable : bool selectionBehaviorOnRemove : SelectionBehavior shape : Shape tabsClosable : bool usesScrollButtons : bool

Public Functions

	QTabBar(QWidget *parent = nullptr)
virtual	~QTabBar()
QString	accessibleTabName(int index) const
int	addTab(const QString &text)
int	addTab(const QIcon &icon, const QString &text)
bool	autoHide() const
bool	changeCurrentOnDrag() const
int	count() const
int	currentIndex() const
bool	documentMode() const
bool	drawBase() const
Qt::TextElideMode	elideMode() const
bool	expanding() const
QSize	iconSize() const
int	insertTab(int index, const QString &text)
int	insertTab(int index, const QIcon &icon, const QString &text)
bool	isMovable() const
bool	isTabEnabled(int index) const
void	moveTab(int from, int to)
void	removeTab(int index)
QTabBar::SelectionBehavior	selectionBehaviorOnRemove() const
void	setAccessibleTabName(int index, const QString &name)
void	setAutoHide(bool hide)
void	setChangeCurrentOnDrag(bool change)
void	setDocumentMode(bool set)
void	setDrawBase(bool drawTheBase)
void	setElideMode(Qt::TextElideMode)
void	setExpanding(bool enabled)
void	setIconSize(const QSize &size)
void	setMovable(bool movable)
void	setSelectionBehaviorOnRemove(QTabBar::SelectionBehavior behavior)
void	setShape(QTabBar::Shape shape)
void	setTabButton(int index, QTabBar::ButtonPosition position, QWidget *widget)
void	setTabData(int index, const QVariant &data)
void	setTabEnabled(int index, bool enabled)
void	setTabIcon(int index, const QIcon &icon)
void	setTabText(int index, const QString &text)
void	setTabTextColor(int index, const QColor &color)
void	setTabToolTip(int index, const QString &tip)
void	setTabWhatsThis(int index, const QString &text)
void	setTabsClosable(bool closable)
void	setUsesScrollButtons(bool useButtons)
QTabBar::Shape	shape() const
int	tabAt(const QPoint &position) const
QWidget *	tabButton(int index, QTabBar::ButtonPosition position) const
QVariant	tabData(int index) const
QIcon	tabIcon(int index) const
QRect	tabRect(int index) const
QString	tabText(int index) const
QColor	tabTextColor(int index) const
QString	tabToolTip(int index) const
QString	tabWhatsThis(int index) const
bool	tabsClosable() const
bool	usesScrollButtons() const

Reimplemented Public Functions

virtual QSize	minimumSizeHint() const override
virtual QSize	sizeHint() const override

Public Slots

void	setCurrentIndex(int index)

Signals

void	currentChanged(int index)
void	tabBarClicked(int index)
void	tabBarDoubleClicked(int index)
void	tabCloseRequested(int index)
void	tabMoved(int from, int to)

Protected Functions

void	initStyleOption(QStyleOptionTab *option, int tabIndex) const
virtual QSize	minimumTabSizeHint(int index) const
virtual void	tabInserted(int index)
virtual void	tabLayoutChange()
virtual void	tabRemoved(int index)
virtual QSize	tabSizeHint(int index) const

Reimplemented Protected Functions

virtual void	changeEvent(QEvent *event) override
virtual bool	event(QEvent *event) override
virtual void	hideEvent(QHideEvent *) override
virtual void	keyPressEvent(QKeyEvent *event) override
virtual void	mouseMoveEvent(QMouseEvent *event) override
virtual void	mousePressEvent(QMouseEvent *event) override
virtual void	mouseReleaseEvent(QMouseEvent *event) override
virtual void	paintEvent(QPaintEvent *) override
virtual void	resizeEvent(QResizeEvent *) override
virtual void	showEvent(QShowEvent *) override
virtual void	timerEvent(QTimerEvent *event) override
virtual void	wheelEvent(QWheelEvent *event) override

Detailed Description

QTabBar is straightforward to use; it draws the tabs using one of the predefined shapes, and emits a signal when a tab is selected. It can be subclassed to tailor the look and feel. Qt also provides a ready-made QTabWidget.

Each tab has a tabText(), an optional tabIcon(), an optional tabToolTip(), optional tabWhatsThis() and optional tabData(). The tabs's attributes can be changed with setTabText(), setTabIcon(), setTabToolTip(), setTabWhatsThis and setTabData(). Each tabs can be enabled or disabled individually with setTabEnabled().

Each tab can display text in a distinct color. The current text color for a tab can be found with the tabTextColor() function. Set the text color for a particular tab with setTabTextColor().

Tabs are added using addTab(), or inserted at particular positions using insertTab(). The total number of tabs is given by count(). Tabs can be removed from the tab bar with removeTab(). Combining removeTab() and insertTab() allows you to move tabs to different positions.

The shape property defines the tabs' appearance. The choice of shape is a matter of taste, although tab dialogs (for preferences and similar) invariably use RoundedNorth. Tab controls in windows other than dialogs almost always use either RoundedSouth or TriangularSouth. Many spreadsheets and other tab controls in which all the pages are essentially similar use TriangularSouth, whereas RoundedSouth is used mostly when the pages are different (e.g. a multi-page tool palette). The default in QTabBar is RoundedNorth.

The most important part of QTabBar's API is the currentChanged() signal. This is emitted whenever the current tab changes (even at startup, when the current tab changes from 'none'). There is also a slot, setCurrentIndex(), which can be used to select a tab programmatically. The function currentIndex() returns the index of the current tab, count holds the number of tabs.

QTabBar creates automatic mnemonic keys in the manner of QAbstractButton; e.g. if a tab's label is "&Graphics", Alt+G becomes a shortcut key for switching to that tab.

The following virtual functions may need to be reimplemented in order to tailor the look and feel or store extra data with each tab:

• tabSizeHint() calcuates the size of a tab.
• tabInserted() notifies that a new tab was added.
• tabRemoved() notifies that a tab was removed.
• tabLayoutChange() notifies that the tabs have been re-laid out.
• paintEvent() paints all tabs.

For subclasses, you might also need the tabRect() functions which returns the visual geometry of a single tab.

	A tab bar shown in the Fusion widget style.
	A truncated tab bar shown in the Fusion widget style.

See also QTabWidget.

Member Type Documentation

enum QTabBar::ButtonPosition

This enum type lists the location of the widget on a tab.

Constant	Value	Description
QTabBar::LeftSide	0	Left side of the tab.
QTabBar::RightSide	1	Right side of the tab.

This enum was introduced or modified in Qt 4.5.

enum QTabBar::SelectionBehavior

This enum type lists the behavior of QTabBar when a tab is removed and the tab being removed is also the current tab.

Constant	Value	Description
QTabBar::SelectLeftTab	0	Select the tab to the left of the one being removed.
QTabBar::SelectRightTab	1	Select the tab to the right of the one being removed.
QTabBar::SelectPreviousTab	2	Select the previously selected tab.

This enum was introduced or modified in Qt 4.5.

enum QTabBar::Shape

This enum type lists the built-in shapes supported by QTabBar. Treat these as hints as some styles may not render some of the shapes. However, position should be honored.

Constant	Value	Description
QTabBar::RoundedNorth	0	The normal rounded look above the pages
QTabBar::RoundedSouth	1	The normal rounded look below the pages
QTabBar::RoundedWest	2	The normal rounded look on the left side of the pages
QTabBar::RoundedEast	3	The normal rounded look on the right side the pages
QTabBar::TriangularNorth	4	Triangular tabs above the pages.
QTabBar::TriangularSouth	5	Triangular tabs similar to those used in the Excel spreadsheet, for example
QTabBar::TriangularWest	6	Triangular tabs on the left of the pages.
QTabBar::TriangularEast	7	Triangular tabs on the right of the pages.

Member Function Documentation

QTabBar::QTabBar(QWidget *parent = nullptr)

Creates a new tab bar with the given parent.

[signal] void QTabBar::currentChanged(int index)

This signal is emitted when the tab bar's current tab changes. The new current has the given index, or -1 if there isn't a new one (for example, if there are no tab in the QTabBar)

Note: Notifier signal for property currentIndex.

[signal] void QTabBar::tabBarClicked(int index)

This signal is emitted when user clicks on a tab at an index.

index is the index of a clicked tab, or -1 if no tab is under the cursor.

This function was introduced in Qt 5.2.

[signal] void QTabBar::tabBarDoubleClicked(int index)

This signal is emitted when the user double clicks on a tab at index.

index refers to the tab clicked, or -1 if no tab is under the cursor.

This function was introduced in Qt 5.2.

[signal] void QTabBar::tabCloseRequested(int index)

This signal is emitted when the close button on a tab is clicked. The index is the index that should be removed.

This function was introduced in Qt 4.5.

See also setTabsClosable().

[signal] void QTabBar::tabMoved(int from, int to)

This signal is emitted when the tab has moved the tab at index position from to index position to.

note: QTabWidget will automatically move the page when this signal is emitted from its tab bar.

This function was introduced in Qt 4.5.

See also moveTab().

[virtual] QTabBar::~QTabBar()

Destroys the tab bar.

QString QTabBar::accessibleTabName(int index) const

Returns the accessibleName of the tab at position index, or an empty string if index is out of range.

See also setAccessibleTabName().

int QTabBar::addTab(const QString &text)

Adds a new tab with text text. Returns the new tab's index.

int QTabBar::addTab(const QIcon &icon, const QString &text)

This is an overloaded function.

Adds a new tab with icon icon and text text. Returns the new tab's index.

[override virtual protected] void QTabBar::changeEvent(QEvent *event)

Reimplements: QWidget::changeEvent(QEvent *event).

[override virtual protected] bool QTabBar::event(QEvent *event)

Reimplements: QWidget::event(QEvent *event).

[override virtual protected] void QTabBar::hideEvent(QHideEvent *)

Reimplements: QWidget::hideEvent(QHideEvent *event).

[protected] void QTabBar::initStyleOption(QStyleOptionTab *option, int tabIndex) const

Initialize option with the values from the tab at tabIndex. This method is useful for subclasses when they need a QStyleOptionTab, but don't want to fill in all the information themselves.

See also QStyleOption::initFrom() and QTabWidget::initStyleOption().

int QTabBar::insertTab(int index, const QString &text)

Inserts a new tab with text text at position index. If index is out of range, the new tab is appened. Returns the new tab's index.

int QTabBar::insertTab(int index, const QIcon &icon, const QString &text)

This is an overloaded function.

Inserts a new tab with icon icon and text text at position index. If index is out of range, the new tab is appended. Returns the new tab's index.

If the QTabBar was empty before this function is called, the inserted tab becomes the current tab.

Inserting a new tab at an index less than or equal to the current index will increment the current index, but keep the current tab.

bool QTabBar::isTabEnabled(int index) const

Returns true if the tab at position index is enabled; otherwise returns false.

[override virtual protected] void QTabBar::keyPressEvent(QKeyEvent *event)

Reimplements: QWidget::keyPressEvent(QKeyEvent *event).

[override virtual] QSize QTabBar::minimumSizeHint() const

Reimplements an access function for property: QWidget::minimumSizeHint.

[virtual protected] QSize QTabBar::minimumTabSizeHint(int index) const

Returns the minimum tab size hint for the tab at position index.

This function was introduced in Qt 5.0.

[override virtual protected] void QTabBar::mouseMoveEvent(QMouseEvent *event)

Reimplements: QWidget::mouseMoveEvent(QMouseEvent *event).

[override virtual protected] void QTabBar::mousePressEvent(QMouseEvent *event)

Reimplements: QWidget::mousePressEvent(QMouseEvent *event).

[override virtual protected] void QTabBar::mouseReleaseEvent(QMouseEvent *event)

Reimplements: QWidget::mouseReleaseEvent(QMouseEvent *event).

void QTabBar::moveTab(int from, int to)

Moves the item at index position from to index position to.

This function was introduced in Qt 4.5.

See also tabMoved() and tabLayoutChange().

[override virtual protected] void QTabBar::paintEvent(QPaintEvent *)

Reimplements: QWidget::paintEvent(QPaintEvent *event).

void QTabBar::removeTab(int index)

Removes the tab at position index.

See also SelectionBehavior.

[override virtual protected] void QTabBar::resizeEvent(QResizeEvent *)

Reimplements: QWidget::resizeEvent(QResizeEvent *event).

void QTabBar::setAccessibleTabName(int index, const QString &name)

Sets the accessibleName of the tab at position index to name.

See also accessibleTabName().

void QTabBar::setTabButton(int index, QTabBar::ButtonPosition position, QWidget *widget)

Sets widget on the tab index. The widget is placed on the left or right hand side depending upon the position.

Any previously set widget in position is hidden.

The tab bar will take ownership of the widget and so all widgets set here will be deleted by the tab bar when it is destroyed unless you separately reparent the widget after setting some other widget (or nullptr).

This function was introduced in Qt 4.5.

See also tabButton() and tabsClosable().

void QTabBar::setTabData(int index, const QVariant &data)

Sets the data of the tab at position index to data.

See also tabData().

void QTabBar::setTabEnabled(int index, bool enabled)

If enabled is true then the tab at position index is enabled; otherwise the item at position index is disabled.

See also isTabEnabled().

void QTabBar::setTabIcon(int index, const QIcon &icon)

Sets the icon of the tab at position index to icon.

See also tabIcon().

void QTabBar::setTabText(int index, const QString &text)

Sets the text of the tab at position index to text.

See also tabText().

void QTabBar::setTabTextColor(int index, const QColor &color)

Sets the color of the text in the tab with the given index to the specified color.

If an invalid color is specified, the tab will use the QTabBar foreground role instead.

See also tabTextColor().

void QTabBar::setTabToolTip(int index, const QString &tip)

Sets the tool tip of the tab at position index to tip.

See also tabToolTip().

void QTabBar::setTabWhatsThis(int index, const QString &text)

Sets the What's This help text of the tab at position index to text.

This function was introduced in Qt 4.1.

See also tabWhatsThis().

[override virtual protected] void QTabBar::showEvent(QShowEvent *)

Reimplements: QWidget::showEvent(QShowEvent *event).

[override virtual] QSize QTabBar::sizeHint() const

Reimplements an access function for property: QWidget::sizeHint.

int QTabBar::tabAt(const QPoint &position) const

Returns the index of the tab that covers position or -1 if no tab covers position;

This function was introduced in Qt 4.3.

QWidget *QTabBar::tabButton(int index, QTabBar::ButtonPosition position) const

Returns the widget set a tab index and position or nullptr if one is not set.

See also setTabButton().

QVariant QTabBar::tabData(int index) const

Returns the data of the tab at position index, or a null variant if index is out of range.

See also setTabData().

QIcon QTabBar::tabIcon(int index) const

Returns the icon of the tab at position index, or a null icon if index is out of range.

See also setTabIcon().

[virtual protected] void QTabBar::tabInserted(int index)

This virtual handler is called after a new tab was added or inserted at position index.

See also tabRemoved().

[virtual protected] void QTabBar::tabLayoutChange()

This virtual handler is called whenever the tab layout changes.

See also tabRect().

QRect QTabBar::tabRect(int index) const

Returns the visual rectangle of the tab at position index, or a null rectangle if index is out of range.

[virtual protected] void QTabBar::tabRemoved(int index)

This virtual handler is called after a tab was removed from position index.

See also tabInserted().

[virtual protected] QSize QTabBar::tabSizeHint(int index) const

Returns the size hint for the tab at position index.

QString QTabBar::tabText(int index) const

Returns the text of the tab at position index, or an empty string if index is out of range.

See also setTabText().

QColor QTabBar::tabTextColor(int index) const

Returns the text color of the tab with the given index, or a invalid color if index is out of range.

See also setTabTextColor().

QString QTabBar::tabToolTip(int index) const

Returns the tool tip of the tab at position index, or an empty string if index is out of range.

See also setTabToolTip().

QString QTabBar::tabWhatsThis(int index) const

Returns the What's This help text of the tab at position index, or an empty string if index is out of range.

This function was introduced in Qt 4.1.

See also setTabWhatsThis().

[override virtual protected] void QTabBar::timerEvent(QTimerEvent *event)

Reimplements: QObject::timerEvent(QTimerEvent *event).

[override virtual protected] void QTabBar::wheelEvent(QWheelEvent *event)

Reimplements: QWidget::wheelEvent(QWheelEvent *event).