QMdiSubWindow Class

The QMdiSubWindow class is a window inside a QMdiArea. More…

Header	`#include <QMdiSubWindow>`
CMake	`target_link_libraries(app PRIVATE Nt::Widgets)`
Module	Nt Widgets C++ Classes
Inherits	QWidget

List of all members, including inherited members

Public Types

enum	SubWindowOption
typedef	SubWindowOptions

Public Functions

	QMdiSubWindow(QWidget *parent = nullptr, Qt::WindowFlags flags = Qt::WindowFlags())
	~QMdiSubWindow()
void	setWidget(QWidget *widget)
QWidget *	widget() const
QMdiArea *	mdiArea() const
void	setOption(SubWindowOption option, bool on = true)
bool	testOption(SubWindowOption option) const
Qt::WindowStates	windowState() const
bool	isMaximized() const
bool	isMinimized() const

Reimplemented Public Functions

QSize	sizeHint() const
QSize	minimumSizeHint() const

Public Slots

void	showMaximized()
void	showMinimized()
void	showNormal()

Signals

void	aboutToActivate()
void	windowStateChanged(Qt::WindowStates oldState, Qt::WindowStates newState)

Reimplemented Protected Functions

void	paintEvent(QPaintEvent *event)
void	resizeEvent(QResizeEvent *event)
void	mousePressEvent(QMouseEvent *event)
void	mouseMoveEvent(QMouseEvent *event)
void	mouseReleaseEvent(QMouseEvent *event)
void	mouseDoubleClickEvent(QMouseEvent *event)
void	closeEvent(QCloseEvent *event)
void	changeEvent(QEvent *event)
void	focusInEvent(QFocusEvent *event)

Detailed Description

A sub-window has a title bar with the window title and buttons that minimize, maximize and close it, and a widget under it. QMdiArea::addSubWindow() makes one for a widget:

QMdiSubWindow *window = area->addSubWindow(new QPlainTextEdit);
window->setWindowTitle("Notes");
window->show();

The user moves the sub-window by its title bar and resizes it by its edges; double-clicking the title bar maximizes it or makes it normal again. A maximized sub-window fills the area and follows its size; a minimized one is only its title bar. Closing a sub-window sends a close event to its widget, and deletes the sub-window if the widget accepts it. The window title follows that of the widget.

See also QMdiArea.

Differences from Qt

The buttons show "-", "+", "=" and "x" rather than icons, and there is no system menu, no shading (showShaded()) and no keyboard moving and resizing. The sub-window options are recorded only; moving and resizing are never shown with a rubber band. showMaximized(), showMinimized() and showNormal() are functions of the sub-window, since QWidget has no window states in Nt.

Member Type Documentation

enum QMdiSubWindow::SubWindowOption

Options of a sub-window; recorded only. SubWindowOptions is a typedef for QFlags<SubWindowOption>.

Constant	Description
`QMdiSubWindow::AllowOutsideAreaHorizontally`	The sub-window may be moved out of the area at the sides.
`QMdiSubWindow::AllowOutsideAreaVertically`	The sub-window may be moved out of the area at the top and the bottom.
`QMdiSubWindow::RubberBandResize`	Resizing shows a rubber band.
`QMdiSubWindow::RubberBandMove`	Moving shows a rubber band.

typedef QMdiSubWindow::SubWindowOptions

The SubWindowOptions type is a typedef for QFlags<SubWindowOption>. It stores an OR combination of SubWindowOption values.

Member Function Documentation

[explicit] QMdiSubWindow::QMdiSubWindow(QWidget **parent* = nullptr, Qt::WindowFlags flags = Qt::WindowFlags())

Constructs an empty sub-window with the given parent and window flags; Qt::FramelessWindowHint leaves out the frame and the title bar.

[override] QMdiSubWindow::~QMdiSubWindow()

Destroys the sub-window and its widget; the area forgets it.

[signal] void QMdiSubWindow::aboutToActivate()

This signal is emitted just before the sub-window becomes the active one.

[override, protected] void QMdiSubWindow::changeEvent(QEvent **event*)

Reimplements QWidget::changeEvent().

[override, protected] void QMdiSubWindow::closeEvent(QCloseEvent **event*)

Reimplements QWidget::closeEvent().

The close event goes to the widget first; if the widget accepts it, the sub-window is hidden, leaves its area and is deleted later.

[override, protected] void QMdiSubWindow::focusInEvent(QFocusEvent **event*)

Reimplements QWidget::focusInEvent().

Getting the focus activates the sub-window.

bool QMdiSubWindow::isMaximized() const

Returns whether the sub-window is maximized.

bool QMdiSubWindow::isMinimized() const

Returns whether the sub-window is minimized.

QMdiArea * QMdiSubWindow::mdiArea() const

Returns the area that the sub-window is in, or nullptr.

[override] QSize QMdiSubWindow::minimumSizeHint() const

Reimplements QWidget::minimumSizeHint().

[override, protected] void QMdiSubWindow::mouseDoubleClickEvent(QMouseEvent **event*)

Reimplements QWidget::mouseDoubleClickEvent().

Double-clicking the title bar maximizes the sub-window, or makes it normal again.

[override, protected] void QMdiSubWindow::mouseMoveEvent(QMouseEvent **event*)

Reimplements QWidget::mouseMoveEvent().

[override, protected] void QMdiSubWindow::mousePressEvent(QMouseEvent **event*)

Reimplements QWidget::mousePressEvent().

A press activates the sub-window, and starts moving it by the title bar or resizing it by an edge.

[override, protected] void QMdiSubWindow::mouseReleaseEvent(QMouseEvent **event*)

Reimplements QWidget::mouseReleaseEvent().

[override, protected] void QMdiSubWindow::paintEvent(QPaintEvent **event*)

Reimplements QWidget::paintEvent().

[override, protected] void QMdiSubWindow::resizeEvent(QResizeEvent **event*)

Reimplements QWidget::resizeEvent().

void QMdiSubWindow::setOption(SubWindowOption option, bool on = true)

Sets option if on is true, and clears it otherwise.

void QMdiSubWindow::setWidget(QWidget **widget*)

Makes widget the widget of the sub-window, under the title bar. The sub-window takes it as a child; the widget it had is deleted. The window title follows that of the widget.

See also widget().

[slot] void QMdiSubWindow::showMaximized()

Maximizes the sub-window: it fills its area, and follows the size of the area.

See also showNormal().

[slot] void QMdiSubWindow::showMinimized()

Minimizes the sub-window to its title bar.

See also showNormal().

[slot] void QMdiSubWindow::showNormal()

Makes the sub-window normal again, with the geometry it had before it was maximized or minimized.

[override] QSize QMdiSubWindow::sizeHint() const

Reimplements QWidget::sizeHint().

bool QMdiSubWindow::testOption(SubWindowOption option) const

Returns whether option is set.

Returns the widget of the sub-window, or nullptr.

Qt::WindowStates QMdiSubWindow::windowState() const

Returns the state of the sub-window: whether it is maximized, minimized or active.

[signal] void QMdiSubWindow::windowStateChanged(Qt::WindowStates oldState, Qt::WindowStates newState)

This signal is emitted when the state of the sub-window changes from oldState to newState.