QClipboard Class Reference

Detailed Description

The clipboard offers a simple mechanism to copy and paste data between applications.

QClipboard supports the same data types that QDragObject does, and uses similar mechanisms. For advanced clipboard usage read the drag-and-drop documentation.

There is a single QClipboard object in an application, and you can access it using QApplication::clipboard().

Example:

    QClipboard *cb = QApplication::clipboard();
    QString text;

    // Copy text from the clipboard (paste)
    text = cb->text();
    if ( text )
        qDebug( "The clipboard contains: %s", text );

    // Copy text into the clipboard
    cb->setText( "This text can be pasted by other programs" );
    

QClipboard features some convenience functions to access common data types: setText() allows the exchange of Unicode text and setPixmap() and setImage() allows the exchange of QPixmaps and QImages between applications. The setData() function is the ultimate in flexibility: it allows you to add any QMimeSource into the clipboard. There are corresponding getters for each of these, e.g. text(), image() and pixmap().

You can clear the clipboard by calling clear().

The underlying clipboards of the X Window system and MS Windows differ. The X Window system has a concept of selection -- when text is selected, it is immediately available in the selection buffer; MS Windows only adds text to the clipboard when an explicit copy or cut is made. The X Window system also has a concept of ownership; if you change the selection within a window, X11 will only notify the owner and the previous owner of the change; in MS Windows the clipboard is a fully global resource so all applications are notified of changes. See the multiclip example in the Qt Designer examples directory for an example of a multiplatform clipboard application that also demonstrates selection handling.

See also Environment Classes and Input/Output and Networking.

Member Function Documentation

void QClipboard::clear ()

QMimeSource * QClipboard::data () const

void QClipboard::dataChanged () [signal]

This signal is emitted when the clipboard data is changed.

QImage QClipboard::image () const

See also setImage(), pixmap(), data() and QImage::isNull().

bool QClipboard::ownsClipboard () const

bool QClipboard::ownsSelection () const

QPixmap QClipboard::pixmap () const

See also setPixmap(), image(), data() and QPixmap::convertFromImage().

void QClipboard::selectionChanged () [signal]

This signal is emitted when the selection is changed. This only applies to windowing systems that support selections, e.g. X11. Windows doesn't support selections.

bool QClipboard::selectionModeEnabled () const

See also setSelectionMode() and supportsSelection().

void QClipboard::setData ( QMimeSource * src )

The QDragObject subclasses are reasonable objects to put into the clipboard (but do not try to call QDragObject::drag() on the same object). Any QDragObject placed in the clipboard should have a parent of 0. Do not put QDragMoveEvent or QDropEvent subclasses in the clipboard, as they do not belong to the event handler which receives them.

The setText() and setPixmap() functions are simpler wrappers for setting text and image data respectively.

void QClipboard::setImage ( const QImage & image )

This is shorthand for:

        setData(new QImageDrag(image))
    

See also image(), setPixmap() and setData().

void QClipboard::setPixmap ( const QPixmap & pixmap )

See also pixmap(), setImage() and setData().

void QClipboard::setSelectionMode ( bool enable )

See also supportsSelection() and selectionModeEnabled().

void QClipboard::setText ( const QString & text )

See also text() and setData().

bool QClipboard::supportsSelection () const

QString QClipboard::text ( QCString & subtype ) const

Common values for subtype are "plain" and "html".

See also setText(), data() and QString::operator!().

QString QClipboard::text () const

Returns the clipboard text as plain text, or a null string if the clipboard does not contain any text.

See also setText(), data() and QString::operator!().

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