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QKeySequence Class Reference
^{[QtGui module]}

The QKeySequence class encapsulates a key sequence as used by shortcuts. More...

Types

• enum SequenceFormat { NativeText, PortableText }
• enum SequenceMatch { NoMatch, PartialMatch, ExactMatch }
• enum StandardKey { UnknownKey, HelpContents, WhatsThis, Open, ..., Quit }

Methods

• __init__ (self)
• __init__ (self, QKeySequence ks)
• __init__ (self, QString key, SequenceFormat format)
• __init__ (self, int k1, int key2 = 0, int key3 = 0, int key4 = 0)
• __init__ (self, QVariant variant)
• int count (self)
• bool isDetached (self)
• bool isEmpty (self)
• SequenceMatch matches (self, QKeySequence seq)
• swap (self, QKeySequence other)
• QString toString (self, SequenceFormat format = QKeySequence.PortableText)

Static Methods

• QKeySequence fromString (QString str, SequenceFormat format = QKeySequence.PortableText)
• list-of-QKeySequence keyBindings (StandardKey key)
• QKeySequence mnemonic (QString text)

Special Methods

• bool __eq__ (self, QKeySequence other)
• bool __ge__ (self, QKeySequence other)
• int __getitem__ (self, int i)
• bool __gt__ (self, QKeySequence other)
• int __int__ (self)
• bool __le__ (self, QKeySequence other)
• __len__ (self)
• bool __lt__ (self, QKeySequence ks)
• bool __ne__ (self, QKeySequence other)

StandardKey, QString or a Python int object may be used whenever QKeySequence is expected.

The QKeySequence class encapsulates a key sequence as used by shortcuts.

In its most common form, a key sequence describes a combination of keys that must be used together to perform some action. Key sequences are used with QAction objects to specify which keyboard shortcuts can be used to trigger actions.

Key sequences can be constructed for use as keyboard shortcuts in three different ways:

• For standard shortcuts, a standard key can be used to request the platform-specific key sequence associated with each shortcut.
• For custom shortcuts, human-readable strings such as "Ctrl+X" can be used, and these can be translated into the appropriate shortcuts for users of different languages. Translations are made in the "QShortcut" context.
• For hard-coded shortcuts, integer key codes can be specified with a combination of values defined by the Qt.Key and Qt.Modifier enum values. Each key code consists of a single Qt.Key value and zero or more modifiers, such as Qt.SHIFT, Qt.CTRL, Qt.ALT and Qt.META.

For example, Ctrl P might be a sequence used as a shortcut for printing a document, and can be specified in any of the following ways:

 QKeySequence(QKeySequence.Print);
 QKeySequence(tr("Ctrl+P"));
 QKeySequence(tr("Ctrl+p"));
 QKeySequence(Qt.CTRL + Qt.Key_P);

Note that, for letters, the case used in the specification string does not matter. In the above examples, the user does not need to hold down the Shift key to activate a shortcut specified with "Ctrl+P". However, for other keys, the use of Shift as an unspecified extra modifier key can lead to confusion for users of an application whose keyboards have different layouts to those used by the developers. See the Keyboard Layout Issues section below for more details.

It is preferable to use standard shortcuts where possible. When creating key sequences for non-standard shortcuts, you should use human-readable strings in preference to hard-coded integer values.

QKeySequence objects can be cast to a QString to obtain a human-readable translated version of the sequence. Similarly, the toString() function produces human-readable strings for use in menus. On Mac OS X, the appropriate symbols are used to describe keyboard shortcuts using special keys on the Macintosh keyboard.

An alternative way to specify hard-coded key codes is to use the Unicode code point of the character; for example, 'A' gives the same key sequence as Qt.Key_A.

Note: On Mac OS X, references to "Ctrl", Qt.CTRL, Qt.Control and Qt.ControlModifier correspond to the Command keys on the Macintosh keyboard, and references to "Meta", Qt.META, Qt.Meta and Qt.MetaModifier correspond to the Control keys. Developers on Mac OS X can use the same shortcut descriptions across all platforms, and their applications will automatically work as expected on Mac OS X.

QKeySequence defines many standard keyboard shortcuts to reduce the amount of effort required when setting up actions in a typical application. The table below shows some common key sequences that are often used for these standard shortcuts by applications on four widely-used platforms. Note that on Mac OS X, the Ctrl value corresponds to the Command keys on the Macintosh keyboard, and the Meta value corresponds to the Control keys.

Note that, since the key sequences used for the standard shortcuts differ between platforms, you still need to test your shortcuts on each platform to ensure that you do not unintentionally assign the same key sequence to many actions.

As a result, both human-readable strings and hard-coded key codes can both be problematic to use when specifying a key sequence that can be used on a variety of different keyboard layouts. Only the use of standard shortcuts guarantees that the user will be able to use the shortcuts that the developer intended.

Despite this, we can address this issue by ensuring that human-readable strings are used, making it possible for translations of key sequences to be made for users of different languages. This approach will be successful for users whose keyboards have the most typical layout for the language they are using.

Key sequences similar to those used in GNU Emacs, allowing up to four key codes, can be created by using the multiple argument constructor, or by passing a human-readable string of comma-separated key sequences.

For example, the key sequence, Ctrl X followed by Ctrl C, can be specified using either of the following ways:

 QKeySequence(tr("Ctrl+X, Ctrl+C"));
 QKeySequence(Qt.CTRL + Qt.Key_X, Qt.CTRL + Qt.Key_C);

Warning: A QApplication instance must have been constructed before a QKeySequence is created; otherwise, your application may crash.

Type Documentation

QKeySequence.SequenceFormat

QKeySequence.SequenceMatch

QKeySequence.StandardKey

This enum represent standard key bindings. They can be used to assign platform dependent keyboard shortcuts to a QAction.

Note that the key bindings are platform dependent. The currently bound shortcuts can be queried using keyBindings().

This enum was introduced or modified in Qt 4.2.

Method Documentation

QKeySequence.__init__ (self)

Constructs an empty key sequence.

QKeySequence.__init__ (self, QKeySequence ks)

Creates a key sequence from the key string. For example "Ctrl+O" gives CTRL+'O'. The strings "Ctrl", "Shift", "Alt" and "Meta" are recognized, as well as their translated equivalents in the "QShortcut" context (using QObject.tr()).

Up to four key codes may be entered by separating them with commas, e.g. "Alt+X,Ctrl+S,Q".

key should be in NativeText format.

This constructor is typically used with tr(), so that shortcut keys can be replaced in translations:

 QMenu *file = new QMenu(this);
 file->addAction(tr("&Open..."), this, SLOT(open()),
                   QKeySequence(tr("Ctrl+O", "File|Open")));

Note the "File|Open" translator comment. It is by no means necessary, but it provides some context for the human translator.

QKeySequence.__init__ (self, QString key, SequenceFormat format)

Creates a key sequence from the key string based on format.

This function was introduced in Qt 4.7.

QKeySequence.__init__ (self, int k1, int key2 = 0, int key3 = 0, int key4 = 0)

Constructs a key sequence with up to 4 keys k1, k2, k3 and k4.

The key codes are listed in Qt.Key and can be combined with modifiers (see Qt.Modifier) such as Qt.SHIFT, Qt.CTRL, Qt.ALT, or Qt.META.

QKeySequence.__init__ (self, QVariant variant)

Copy constructor. Makes a copy of keysequence.

int QKeySequence.count (self)

Returns the number of keys in the key sequence. The maximum is 4.

QKeySequence QKeySequence.fromString (QString str, SequenceFormat format = QKeySequence.PortableText)

Return a QKeySequence from the string str based on format.

This function was introduced in Qt 4.1.

See also toString().

bool QKeySequence.isDetached (self)

bool QKeySequence.isEmpty (self)

Returns true if the key sequence is empty; otherwise returns false.

list-of-QKeySequence QKeySequence.keyBindings (StandardKey key)

Returns a list of key bindings for the given key. The result of calling this function will vary based on the target platform. The first element of the list indicates the primary shortcut for the given platform. If the result contains more than one result, these can be considered alternative shortcuts on the same platform for the given key.

This function was introduced in Qt 4.2.

SequenceMatch QKeySequence.matches (self, QKeySequence seq)

Matches the sequence with seq. Returns ExactMatch if successful, PartialMatch if seq matches incompletely, and NoMatch if the sequences have nothing in common. Returns NoMatch if seq is shorter.

QKeySequence QKeySequence.mnemonic (QString text)

Returns the shortcut key sequence for the mnemonic in text, or an empty key sequence if no mnemonics are found.

For example, mnemonic("E&xit") returns Qt.ALT+Qt.Key_X, mnemonic("&Quit") returns ALT+Key_Q, and mnemonic("Quit") returns an empty QKeySequence.

We provide a list of common mnemonics in English. At the time of writing, Microsoft and Open Group do not appear to have issued equivalent recommendations for other languages.

See also qt_set_sequence_auto_mnemonic().

QKeySequence.swap (self, QKeySequence other)

Swaps key sequence other with this key sequence. This operation is very fast and never fails.

This function was introduced in Qt 4.8.

QString QKeySequence.toString (self, SequenceFormat format = QKeySequence.PortableText)

Return a string representation of the key sequence, based on format.

For example, the value Qt.CTRL+Qt.Key_O results in "Ctrl+O". If the key sequence has multiple key codes, each is separated by commas in the string returned, such as "Alt+X, Ctrl+Y, Z". The strings, "Ctrl", "Shift", etc. are translated using QObject.tr() in the "QShortcut" context.

If the key sequence has no keys, an empty string is returned.

On Mac OS X, the string returned resembles the sequence that is shown in the menu bar.

This function was introduced in Qt 4.1.

See also fromString().

bool QKeySequence.__eq__ (self, QKeySequence other)

bool QKeySequence.__ge__ (self, QKeySequence other)

int QKeySequence.__getitem__ (self, int i)

bool QKeySequence.__gt__ (self, QKeySequence other)

int QKeySequence.__int__ (self)

bool QKeySequence.__le__ (self, QKeySequence other)

QKeySequence.__len__ (self)

bool QKeySequence.__lt__ (self, QKeySequence ks)

bool QKeySequence.__ne__ (self, QKeySequence other)