QMdiArea Class

     QMainWindow *mainWindow = new QMainWindow;
     mainWindow->setCentralWidget(mdiArea);

Member Function Documentation

QMdiArea::QMdiArea(QWidget *parent = nullptr)

Constructs an empty mdi area. parent is passed to QWidget's constructor.

[virtual noexcept] QMdiArea::~QMdiArea()

Destroys the MDI area.

[slot] void QMdiArea::activateNextSubWindow()

Gives the keyboard focus to another window in the list of child windows. The window activated will be the next one determined by the current activation order.

See also activatePreviousSubWindow() and QMdiArea::WindowOrder.

[slot] void QMdiArea::activatePreviousSubWindow()

Gives the keyboard focus to another window in the list of child windows. The window activated will be the previous one determined by the current activation order.

See also activateNextSubWindow() and QMdiArea::WindowOrder.

QMdiSubWindow *QMdiArea::activeSubWindow() const

Returns a pointer to the current active subwindow. If no window is currently active, nullptr is returned.

Subwindows are treated as top-level windows with respect to window state, i.e., if a widget outside the MDI area is the active window, no subwindow will be active. Note that if a widget in the window in which the MDI area lives gains focus, the window will be activated.

See also setActiveSubWindow() and Qt::WindowState.

QMdiSubWindow *QMdiArea::addSubWindow(QWidget *widget, Qt::WindowFlags windowFlags = Qt::WindowFlags())

Adds widget as a new subwindow to the MDI area. If windowFlags are non-zero, they will override the flags set on the widget.

The widget can be either a QMdiSubWindow or another QWidget (in which case the MDI area will create a subwindow and set the widget as the internal widget).

     QMdiArea mdiArea;
     QMdiSubWindow *subWindow1 = new QMdiSubWindow;
     subWindow1->setWidget(internalWidget1);
     subWindow1->setAttribute(Qt::WA_DeleteOnClose);
     mdiArea.addSubWindow(subWindow1);

     QMdiSubWindow *subWindow2 =
         mdiArea.addSubWindow(internalWidget2);

When you create your own subwindow, you must set the Qt::WA_DeleteOnClose widget attribute if you want the window to be deleted when closed in the MDI area. If not, the window will be hidden and the MDI area will not activate the next subwindow.

Returns the QMdiSubWindow that is added to the MDI area.

See also removeSubWindow().

[slot] void QMdiArea::cascadeSubWindows()

Arranges all the child windows in a cascade pattern.

See also tileSubWindows().

[override virtual protected] void QMdiArea::childEvent(QChildEvent *childEvent)

Reimplements: QObject::childEvent(QChildEvent *event).

[slot] void QMdiArea::closeActiveSubWindow()

Closes the active subwindow.

See also closeAllSubWindows().

[slot] void QMdiArea::closeAllSubWindows()

Closes all subwindows by sending a QCloseEvent to each window. You may receive subWindowActivated() signals from subwindows before they are closed (if the MDI area activates the subwindow when another is closing).

Subwindows that ignore the close event will remain open.

See also closeActiveSubWindow().

QMdiSubWindow *QMdiArea::currentSubWindow() const

Returns a pointer to the current subwindow, or nullptr if there is no current subwindow.

This function will return the same as activeSubWindow() if the QApplication containing QMdiArea is active.

See also activeSubWindow() and QApplication::activeWindow().

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

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

[override virtual protected] bool QMdiArea::eventFilter(QObject *object, QEvent *event)

Reimplements: QObject::eventFilter(QObject *watched, QEvent *event).

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

Reimplements: QAbstractScrollArea::minimumSizeHint() const.

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

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

void QMdiArea::removeSubWindow(QWidget *widget)

Removes widget from the MDI area. The widget must be either a QMdiSubWindow or a widget that is the internal widget of a subwindow. Note widget is never actually deleted by QMdiArea. If a QMdiSubWindow is passed in, its parent is set to nullptr and it is removed; but if an internal widget is passed in, the child widget is set to nullptr and the QMdiSubWindow is not removed.

See also addSubWindow().

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

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

[override virtual protected] void QMdiArea::scrollContentsBy(int dx, int dy)

Reimplements: QAbstractScrollArea::scrollContentsBy(int dx, int dy).

[slot] void QMdiArea::setActiveSubWindow(QMdiSubWindow *window)

Activates the subwindow window. If window is nullptr, any current active window is deactivated.

See also activeSubWindow().

void QMdiArea::setOption(QMdiArea::AreaOption option, bool on = true)

If on is true, option is enabled on the MDI area; otherwise it is disabled. See AreaOption for the effect of each option.

See also AreaOption and testOption().

[override virtual protected slot] void QMdiArea::setupViewport(QWidget *viewport)

Reimplements: QAbstractScrollArea::setupViewport(QWidget *viewport).

This slot is called by QAbstractScrollArea after setViewport() has been called. Reimplement this function in a subclass of QMdiArea to initialize the new viewport before it is used.

See also setViewport().

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

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

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

Reimplements: QAbstractScrollArea::sizeHint() const.

[signal] void QMdiArea::subWindowActivated(QMdiSubWindow *window)

QMdiArea emits this signal after window has been activated. When window is nullptr, QMdiArea has just deactivated its last active window, and there are no active windows on the workspace.

See also QMdiArea::activeSubWindow().

QList<QMdiSubWindow *> QMdiArea::subWindowList(QMdiArea::WindowOrder order = CreationOrder) const

Returns a list of all subwindows in the MDI area. If order is CreationOrder (the default), the windows are sorted in the order in which they were inserted into the workspace. If order is StackingOrder, the windows are listed in their stacking order, with the topmost window as the last item in the list. If order is ActivationHistoryOrder, the windows are listed according to their recent activation history.

See also WindowOrder.

bool QMdiArea::testOption(QMdiArea::AreaOption option) const

Returns true if option is enabled; otherwise returns false.

See also AreaOption and setOption().

[slot] void QMdiArea::tileSubWindows()

Arranges all child windows in a tile pattern.

See also cascadeSubWindows().

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

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

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

Reimplements: QAbstractScrollArea::viewportEvent(QEvent *event).