qt QAction Class

Qtドキュメントリンク

https://doc.qt.io/qt-5/qaction.html
以下はQtドキュメントから抜粋して、バージョンは原作者に帰して、筆者は著作権がなくて、また博文を参考にすることができて、この文章はQtドキュメントに対して翻訳するようにしましょう:
https://www.cnblogs.com/weizhixiang/p/5866725.html
 

Public Functions

 
QAction(const QIcon &icon, const QString &text, QObject *parent = nullptr)
 
QAction(const QString &text, QObject *parent = nullptr)
 
QAction(QObject *parent = nullptr)
virtual
~QAction()
QActionGroup *
actionGroup() const
void
activate(QAction::ActionEvent event)
QList
associatedGraphicsWidgets() const
QList
associatedWidgets() const
bool
autoRepeat() const
QVariant
data() const
QFont
font() const
QIcon
icon() const
QString
iconText() const
bool
isCheckable() const
bool
isChecked() const
bool
isEnabled() const
bool
isIconVisibleInMenu() const
bool
isSeparator() const
bool
isShortcutVisibleInContextMenu() const
bool
isVisible() const
QMenu *
menu() const
QAction::MenuRole
menuRole() const
QWidget *
parentWidget() const
QAction::Priority
priority() const
void
setActionGroup(QActionGroup *group)
void
setAutoRepeat(bool)
void
setCheckable(bool)
void
setData(const QVariant &userData)
void
setFont(const QFont &font)
void
setIcon(const QIcon &icon)
void
setIconText(const QString &text)
void
setIconVisibleInMenu(bool visible)
void
setMenu(QMenu *menu)
void
setMenuRole(QAction::MenuRole menuRole)
void
setPriority(QAction::Priority priority)
void
setSeparator(bool b)
void
setShortcut(const QKeySequence &shortcut)
void
setShortcutContext(Qt::ShortcutContext context)
void
setShortcutVisibleInContextMenu(bool show)
void
setShortcuts(const QList &shortcuts)
void
setShortcuts(QKeySequence::StandardKey key)
void
setStatusTip(const QString &statusTip)
void
setText(const QString &text)
void
setToolTip(const QString &tip)
void
setWhatsThis(const QString &what)
QKeySequence
shortcut() const
Qt::ShortcutContext
shortcutContext() const
QList
shortcuts() const
bool
showStatusText(QWidget *widget = nullptr)
QString
statusTip() const
QString
text() const
QString
toolTip() const
QString
whatsThis() const

Detailed Description

In applications many common commands can be invoked via menus, toolbar buttons, and keyboard shortcuts. Since the user expects each command to be performed in the same way, regardless of the user interface used, it is useful to represent each command as an action.
Actions can be added to menus and toolbars, and will automatically keep them in sync. For example, in a word processor, if the user presses a Bold toolbar button, the Bold menu item will automatically be checked.
Actions can be created as independent objects, but they may also be created during the construction of menus; the QMenu class contains convenience functions for creating actions suitable for use as menu items.
A QAction may contain an icon, menu text, a shortcut, status text, "What's This?"text, and a tooltip. Most of these can be set in the constructor. They can also be set independently with setIcon(), setText(), setIconText(), setShortcut(), setStatusTip(), setWhatsThis(), and setToolTip(). For menu items, it is possible to set an individual font with setFont().
Actions are added to widgets using QWidget::addAction() or QGraphicsWidget::addAction(). Note that an action must be added to a widget before it can be used; this is also true when the shortcut should be global (i.e., Qt::ApplicationShortcut as Qt::ShortcutContext).
Once a QAction has been created it should be added to the relevant menu and toolbar, then connected to the slot which will perform the action. For example:

    const QIcon openIcon = QIcon::fromTheme("document-open", QIcon(":/images/open.png"));
    QAction *openAct = new QAction(openIcon, tr("&Open..."), this);
    openAct->setShortcuts(QKeySequence::Open);
    openAct->setStatusTip(tr("Open an existing file"));
    connect(openAct, &QAction::triggered, this, &MainWindow::open);
    fileMenu->addAction(openAct);
    fileToolBar->addAction(openAct);

We recommend that actions are created as children of the window they are used in. In most cases actions will be children of the application's main window.
See also QMenu, QToolBar, and Application Example.