QShortcut Class
The QShortcut class is used to create keyboard shortcuts. More...
| Header: | #include <QShortcut> |
| qmake: | QT += widgets |
| Inherits: | QObject |
Properties
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Public Functions
| QShortcut(const QKeySequence &key, QWidget *parent, const char *member = nullptr, const char *ambiguousMember = nullptr, Qt::ShortcutContext shortcutContext = Qt::WindowShortcut) | |
| QShortcut(QWidget *parent) | |
| virtual | ~QShortcut() |
| bool | autoRepeat() const |
| Qt::ShortcutContext | context() const |
| int | id() const |
| bool | isEnabled() const |
| QKeySequence | key() const |
| QWidget * | parentWidget() const |
| void | setAutoRepeat(bool on) |
| void | setContext(Qt::ShortcutContext context) |
| void | setEnabled(bool enable) |
| void | setKey(const QKeySequence &key) |
| void | setWhatsThis(const QString &text) |
| QString | whatsThis() const |
Signals
| void | activated() |
| void | activatedAmbiguously() |
Detailed Description
The QShortcut class provides a way of connecting keyboard shortcuts to Qt's signals and slots mechanism, so that objects can be informed when a shortcut is executed. The shortcut can be set up to contain all the key presses necessary to describe a keyboard shortcut, including the states of modifier keys such as Shift, Ctrl, and Alt.
On certain widgets, using '&' in front of a character will automatically create a mnemonic (a shortcut) for that character, e.g. "E&xit" will create the shortcut Alt+X (use '&&' to display an actual ampersand). The widget might consume and perform an action on a given shortcut. On X11 the ampersand will not be shown and the character will be underlined. On Windows, shortcuts are normally not displayed until the user presses the Alt key, but this is a setting the user can change. On Mac, shortcuts are disabled by default. Call qt_set_sequence_auto_mnemonic() to enable them. However, because mnemonic shortcuts do not fit in with Aqua's guidelines, Qt will not show the shortcut character underlined.
For applications that use menus, it may be more convenient to use the convenience functions provided in the QMenu class to assign keyboard shortcuts to menu items as they are created. Alternatively, shortcuts may be associated with other types of actions in the QAction class.
The simplest way to create a shortcut for a particular widget is to construct the shortcut with a key sequence. For example:
shortcut = new QShortcut(QKeySequence(tr("Ctrl+O", "File|Open")), parent);
When the user types the key sequence for a given shortcut, the shortcut's activated() signal is emitted. (In the case of ambiguity, the activatedAmbiguously() signal is emitted.) A shortcut is "listened for" by Qt's event loop when the shortcut's parent widget is receiving events.
A shortcut's key sequence can be set with setKey() and retrieved with key(). A shortcut can be enabled or disabled with setEnabled(), and can have "What's This?" help text set with setWhatsThis().
See also QShortcutEvent, QKeySequence, and QAction.
Property Documentation
autoRepeat : bool
This property holds whether the shortcut can auto repeat
If true, the shortcut will auto repeat when the keyboard shortcut combination is held down, provided that keyboard auto repeat is enabled on the system. The default value is true.
This property was introduced in Qt 4.2.
Access functions:
| bool | autoRepeat() const |
| void | setAutoRepeat(bool on) |
context : Qt::ShortcutContext
This property holds the context in which the shortcut is valid
A shortcut's context decides in which circumstances a shortcut is allowed to be triggered. The normal context is Qt::WindowShortcut, which allows the shortcut to trigger if the parent (the widget containing the shortcut) is a subwidget of the active top-level window.
By default, this property is set to Qt::WindowShortcut.
Access functions:
| Qt::ShortcutContext | context() const |
| void | setContext(Qt::ShortcutContext context) |
enabled : bool
This property holds whether the shortcut is enabled
An enabled shortcut emits the activated() or activatedAmbiguously() signal when a QShortcutEvent occurs that matches the shortcut's key() sequence.
If the application is in WhatsThis mode the shortcut will not emit the signals, but will show the "What's This?" text instead.
By default, this property is true.
Access functions:
| bool | isEnabled() const |
| void | setEnabled(bool enable) |
See also whatsThis.
key : QKeySequence
This property holds the shortcut's key sequence
This is a key sequence with an optional combination of Shift, Ctrl, and Alt. The key sequence may be supplied in a number of ways:
setKey(0); // no signal emitted setKey(QKeySequence()); // no signal emitted setKey(0x3b1); // Greek letter alpha setKey(Qt::Key_D); // 'd', e.g. to delete setKey('q'); // 'q', e.g. to quit setKey(Qt::CTRL + Qt::Key_P); // Ctrl+P, e.g. to print document setKey("Ctrl+P"); // Ctrl+P, e.g. to print document
By default, this property contains an empty key sequence.
Access functions:
| QKeySequence | key() const |
| void | setKey(const QKeySequence &key) |
whatsThis : QString
This property holds the shortcut's "What's This?" help text
The text will be shown when the application is in "What's This?" mode and the user types the shortcut key() sequence.
To set "What's This?" help on a menu item (with or without a shortcut key), set the help on the item's action.
By default, this property contains an empty string.
Access functions:
| QString | whatsThis() const |
| void | setWhatsThis(const QString &text) |
See also QWhatsThis::inWhatsThisMode() and QAction::setWhatsThis().
Member Function Documentation
QShortcut::QShortcut(const QKeySequence &key, QWidget *parent, const char *member = nullptr, const char *ambiguousMember = nullptr, Qt::ShortcutContext shortcutContext = Qt::WindowShortcut)
Constructs a QShortcut object for the parent widget. The shortcut operates on its parent, listening for QShortcutEvents that match the key sequence. Depending on the ambiguity of the event, the shortcut will call the member function, or the ambiguousMember function, if the key press was in the shortcut's shortcutContext.
QShortcut::QShortcut(QWidget *parent)
Constructs a QShortcut object for the parent widget. Since no shortcut key sequence is specified, the shortcut will not emit any signals.
See also setKey().
[signal] void QShortcut::activated()
This signal is emitted when the user types the shortcut's key sequence.
See also activatedAmbiguously().
[signal] void QShortcut::activatedAmbiguously()
When a key sequence is being typed at the keyboard, it is said to be ambiguous as long as it matches the start of more than one shortcut.
When a shortcut's key sequence is completed, activatedAmbiguously() is emitted if the key sequence is still ambiguous (i.e., it is the start of one or more other shortcuts). The activated() signal is not emitted in this case.
See also activated().
[virtual] QShortcut::~QShortcut()
Destroys the shortcut.
int QShortcut::id() const
Returns the shortcut's ID.
See also QShortcutEvent::shortcutId().
QWidget *QShortcut::parentWidget() const
Returns the shortcut's parent widget.