Changes to Qt Widgets

The virtual QWidget::enterEvent() handler now receives a QEnterEvent* parameter which has information about the pointer position, rather than a plain QEvent*.

QDesktopWidget was already deprecated in Qt 5, and has been removed in Qt 6, together with QApplication::desktop().

QScreen provides equivalent functionality to query for information about available screens, screen that form a virtual desktop, and screen geometries.

Use QWidget::setScreen() to create a QWidget on a specific display; note that this does not move a widget to a screen in a virtual desktop setup.

These classes have been moved into the QtGui module. Member functions that depend on types defined in QtWidgets (such as QAction::menu() and QAction::setMenu()) are implemented as templates that will be instantiated only when called.

The default timeout parameter for QAbstractButton::animateClick() is removed to allow modern connection syntax without the need for qOverload.

The QComboBox::setModel() function is now virtual.

When QDateTimeEdit::setDateTime() is called with a date-time whose time-spec doesn't match that of the QDateTimeEdit instance, the date-time is converted to the time-spec of the QDateTimeEdit. This gives a date-time that describes the same instant in time, but does so in the same terms as the QDateTimeEdit uses. Previously, the date and time from the passed date-time were combined with the time-spec of the widget, ignoring the time-spec of the date-time; this could describe a different point in time than the one described by the date-time passed.

The virtual viewOptions() method that previously returned a QStyleOptionViewItem object has been renamed to initViewItemOption, and initializes a QStyleOptionViewItem object that's passed in through a pointer.

Styling a widget by its property in Qt 5 vs Qt 6 is different, especially if the property is an enum. In Qt 5, the selector value for such a property is the integer equivalent of the enum value, while in Qt 6 the string value is used. The following example demonstrates this difference:

// Qt 5 style sheet
QToolButton[popupMode="1"] {
    padding-right: 20px;
}

// Qt 6 style sheet
QToolButton[popupMode=MenuButtonPopup] {
    padding-right: 20px;
}

The widget independent classes of the Undo/Redo framework have been moved into the QtGui module.