QKeySequence Class Reference
[QtGui module]

GNU Emacs Style Key Sequences

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.

See also QShortcut.

Member Type Documentation

enum QKeySequence::SequenceFormat

enum QKeySequence::SequenceMatch

enum QKeySequence::StandardKey

This enum represent standard key bindings. They can be used to assign platform dependent keyboard shortcuts to a QAction. QKeyEvent also provides the function QKeyEvent::standardKey() to query if it matches an existing key binding.

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

This enum was introduced in Qt 4.2.

Member Function Documentation

QKeySequence::QKeySequence ()

Constructs an empty key sequence.

QKeySequence::QKeySequence ( const QString & key )

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".

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::QKeySequence ( int k1, int k2 = 0, int k3 = 0, int k4 = 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::QKeySequence ( const QKeySequence & keysequence )

Copy constructor. Makes a copy of keysequence.

QKeySequence::QKeySequence ( StandardKey key )

Constructs a QKeySequence object for the given key. The result will depend on the currently running platform.

The resulting object will be based on the first element in the list of key bindings for the key.

This function was introduced in Qt 4.2.

QKeySequence::~QKeySequence ()

Destroys the key sequence.

uint QKeySequence::count () const

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

QKeySequence QKeySequence::fromString ( const QString & str, SequenceFormat format = PortableText )   [static]

Return a QKeySequence from the string str based on format.

This function was introduced in Qt 4.1.

See also toString().

bool QKeySequence::isEmpty () const

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

QList<QKeySequence> QKeySequence::keyBindings ( StandardKey key )   [static]

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 ( const QKeySequence & seq ) const

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 ( const QString & text )   [static]

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().

QString QKeySequence::toString ( SequenceFormat format = PortableText ) const

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().

QKeySequence::operator QVariant () const

Returns the key sequence as a QVariant

bool QKeySequence::operator!= ( const QKeySequence & other ) const

Returns true if this key sequence is not equal to the other key sequence; otherwise returns false.

bool QKeySequence::operator< ( const QKeySequence & other ) const

Provides an arbitrary comparison of this key sequence and other key sequence. All that is guaranteed is that the operator returns false if both key sequences are equal and that (ks1 < ks2) == !( ks2 < ks1) if the key sequences are not equal.

This function is useful in some circumstances, for example if you want to use QKeySequence objects as keys in a QMap.

See also operator==(), operator!=(), operator>(), operator<=(), and operator>=().

bool QKeySequence::operator<= ( const QKeySequence & other ) const

Returns true if this key sequence is smaller or equal to the other key sequence; otherwise returns false.

See also operator==(), operator!=(), operator<(), operator>(), and operator>=().

QKeySequence & QKeySequence::operator= ( const QKeySequence & other )

Assignment operator. Assigns the other key sequence to this object.

bool QKeySequence::operator== ( const QKeySequence & other ) const

Returns true if this key sequence is equal to the other key sequence; otherwise returns false.

bool QKeySequence::operator> ( const QKeySequence & other ) const

Returns true if this key sequence is larger than the other key sequence; otherwise returns false.

See also operator==(), operator!=(), operator<(), operator<=(), and operator>=().

bool QKeySequence::operator>= ( const QKeySequence & other ) const

Returns true if this key sequence is larger or equal to the other key sequence; otherwise returns false.

See also operator==(), operator!=(), operator<(), operator>(), and operator<=().

int QKeySequence::operator[] ( uint index ) const

Returns a reference to the element at position index in the key sequence. This can only be used to read an element.

Related Non-Members

QDataStream & operator<< ( QDataStream & stream, const QKeySequence & sequence )

This is an overloaded member function, provided for convenience.

Writes the key sequence to the stream.

See also Format of the QDataStream operators.

QDataStream & operator>> ( QDataStream & stream, QKeySequence & sequence )

This is an overloaded member function, provided for convenience.

Reads a key sequence from the stream into the key sequence.

See also Format of the QDataStream operators.