QXmlContentHandler(3qt)QXmlContentHandler(3qt)NAME
QXmlContentHandler - Interface to report the logical content of XML
data
SYNOPSIS
All the functions in this class are reentrant when Qt is built with
thread support.</p>
#include <qxml.h>
Inherited by QXmlDefaultHandler.
Public Members
virtual void setDocumentLocator ( QXmlLocator * locator ) = 0
virtual bool startDocument () = 0
virtual bool endDocument () = 0
virtual bool startPrefixMapping ( const QString & prefix, const QString
& uri ) = 0
virtual bool endPrefixMapping ( const QString & prefix ) = 0
virtual bool startElement ( const QString & namespaceURI, const QString
& localName, const QString & qName, const QXmlAttributes & atts ) =
0
virtual bool endElement ( const QString & namespaceURI, const QString &
localName, const QString & qName ) = 0
virtual bool characters ( const QString & ch ) = 0
virtual bool ignorableWhitespace ( const QString & ch ) = 0
virtual bool processingInstruction ( const QString & target, const
QString & data ) = 0
virtual bool skippedEntity ( const QString & name ) = 0
virtual QString errorString () = 0
DESCRIPTION
The QXmlContentHandler class provides an interface to report the
logical content of XML data.
If the application needs to be informed of basic parsing events, it can
implement this interface and activate it using
QXmlReader::setContentHandler(). The reader can then report basic
document-related events like the start and end of elements and
character data through this interface.
The order of events in this interface is very important, and mirrors
the order of information in the document itself. For example, all of an
element's content (character data, processing instructions, and sub-
elements) appears, in order, between the startElement() event and the
corresponding endElement() event.
The class QXmlDefaultHandler provides a default implementation for this
interface; subclassing from the QXmlDefaultHandler class is very
convenient if you only want to be informed of some parsing events.
The startDocument() function is called at the start of the document,
and endDocument() is called at the end. Before parsing begins
setDocumentLocator() is called. For each element startElement() is
called, with endElement() being called at the end of each element. The
characters() function is called with chunks of character data;
ignorableWhitespace() is called with chunks of whitespace and
processingInstruction() is called with processing instructions. If an
entity is skipped skippedEntity() is called. At the beginning of
prefix-URI scopes startPrefixMapping() is called.
See also the Introduction to SAX2.
See also QXmlDTDHandler, QXmlDeclHandler, QXmlEntityResolver,
QXmlErrorHandler, QXmlLexicalHandler, and XML.
MEMBER FUNCTION DOCUMENTATIONbool QXmlContentHandler::characters ( const QString & ch ) [pure virtual]
The reader calls this function when it has parsed a chunk of character
data (either normal character data or character data inside a CDATA
section; if you need to distinguish between those two types you must
use QXmlLexicalHandler::startCDATA() and
QXmlLexicalHandler::endCDATA()). The character data is reported in ch.
Some readers report whitespace in element content using the
ignorableWhitespace() function rather than using this one.
A reader may report the character data of an element in more than one
chunk; e.g. a reader might want to report "a<b" in three characters()
events ("a ", "<" and " b").
If this function returns FALSE the reader stops parsing and reports an
error. The reader uses the function errorString() to get the error
message.
bool QXmlContentHandler::endDocument () [pure virtual]
The reader calls this function after it has finished parsing. It is
called just once, and is the last handler function called. It is called
after the reader has read all input or has abandoned parsing because of
a fatal error.
If this function returns FALSE the reader stops parsing and reports an
error. The reader uses the function errorString() to get the error
message.
See also startDocument().
bool QXmlContentHandler::endElement ( const QString & namespaceURI, const
QString & localName, const QString & qName ) [pure virtual]
The reader calls this function when it has parsed an end element tag
with the qualified name qName, the local name localName and the
namespace URI namespaceURI.
If this function returns FALSE the reader stops parsing and reports an
error. The reader uses the function errorString() to get the error
message.
See also the namespace description.
See also startElement().
Example: xml/tagreader/structureparser.cpp.
bool QXmlContentHandler::endPrefixMapping ( const QString & prefix ) [pure
virtual]
The reader calls this function to signal the end of a prefix mapping
for the prefix prefix.
If this function returns FALSE the reader stops parsing and reports an
error. The reader uses the function errorString() to get the error
message.
See also the namespace description.
See also startPrefixMapping().
QString QXmlContentHandler::errorString () [pure virtual]
The reader calls this function to get an error string, e.g. if any of
the handler functions returns FALSE.
bool QXmlContentHandler::ignorableWhitespace ( const QString & ch ) [pure
virtual]
Some readers may use this function to report each chunk of whitespace
in element content. The whitespace is reported in ch.
If this function returns FALSE the reader stops parsing and reports an
error. The reader uses the function errorString() to get the error
message.
bool QXmlContentHandler::processingInstruction ( const QString & target, const
QString & data ) [pure virtual]
The reader calls this function when it has parsed a processing
instruction.
target is the target name of the processing instruction and data is the
data in the processing instruction.
If this function returns FALSE the reader stops parsing and reports an
error. The reader uses the function errorString() to get the error
message.
void QXmlContentHandler::setDocumentLocator ( QXmlLocator * locator ) [pure
virtual]
The reader calls this function before it starts parsing the document.
The argument locator is a pointer to a QXmlLocator which allows the
application to get the parsing position within the document.
Do not destroy the locator; it is destroyed when the reader is
destroyed. (Do not use the locator after the reader is destroyed).
bool QXmlContentHandler::skippedEntity ( const QString & name ) [pure virtual]
Some readers may skip entities if they have not seen the declarations
(e.g. because they are in an external DTD). If they do so they report
that they skipped the entity called name by calling this function.
If this function returns FALSE the reader stops parsing and reports an
error. The reader uses the function errorString() to get the error
message.
bool QXmlContentHandler::startDocument () [pure virtual]
The reader calls this function when it starts parsing the document. The
reader calls this function just once, after the call to
setDocumentLocator(), and before any other functions in this class or
in the QXmlDTDHandler class are called.
If this function returns FALSE the reader stops parsing and reports an
error. The reader uses the function errorString() to get the error
message.
See also endDocument().
Example: xml/tagreader/structureparser.cpp.
bool QXmlContentHandler::startElement ( const QString & namespaceURI, const
QString & localName, const QString & qName, const QXmlAttributes & atts
) [pure virtual]
The reader calls this function when it has parsed a start element tag.
There is a corresponding endElement() call when the corresponding end
element tag is read. The startElement() and endElement() calls are
always nested correctly. Empty element tags (e.g. <x/>) cause a
startElement() call to be immediately followed by an endElement() call.
The attribute list provided only contains attributes with explicit
values. The attribute list contains attributes used for namespace
declaration (i.e. attributes starting with xmlns) only if the
namespace-prefix property of the reader is TRUE.
The argument namespaceURI is the namespace URI, or QString::null if the
element has no namespace URI or if no namespace processing is done.
localName is the local name (without prefix), or QString::null if no
namespace processing is done, qName is the qualified name (with prefix)
and atts are the attributes attached to the element. If there are no
attributes, atts is an empty attributes object.
If this function returns FALSE the reader stops parsing and reports an
error. The reader uses the function errorString() to get the error
message.
See also the namespace description.
See also endElement().
Example: xml/tagreader/structureparser.cpp.
bool QXmlContentHandler::startPrefixMapping ( const QString & prefix, const
QString & uri ) [pure virtual]
The reader calls this function to signal the begin of a prefix-URI
namespace mapping scope. This information is not necessary for normal
namespace processing since the reader automatically replaces prefixes
for element and attribute names.
Note that startPrefixMapping() and endPrefixMapping() calls are not
guaranteed to be properly nested relative to each other: all
startPrefixMapping() events occur before the corresponding
startElement() event, and all endPrefixMapping() events occur after the
corresponding endElement() event, but their order is not otherwise
guaranteed.
The argument prefix is the namespace prefix being declared and the
argument uri is the namespace URI the prefix is mapped to.
If this function returns FALSE the reader stops parsing and reports an
error. The reader uses the function errorString() to get the error
message.
See also the namespace description.
See also endPrefixMapping().
SEE ALSO
http://doc.trolltech.com/qxmlcontenthandler.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
license file included in the distribution for a complete license
statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports help us to
help you. Thank you.
The definitive Qt documentation is provided in HTML format; it is
located at $QTDIR/doc/html and can be read using Qt Assistant or with a
web browser. This man page is provided as a convenience for those users
who prefer man pages, although this format is not officially supported
by Trolltech.
If you find errors in this manual page, please report them to qt-
bugs@trolltech.com. Please include the name of the manual page
(qxmlcontenthandler.3qt) and the Qt version (3.3.8).
Trolltech AS 2 February 2007 QXmlContentHandler(3qt)
