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# QXmlNamespaceSupport Class Reference
[QtXml module]

The QXmlNamespaceSupport class is a helper class for XML readers which want to include namespace support. More...

     #include <QXmlNamespaceSupport>

Note: All the functions in this class are reentrant.

This class was introduced in Qt 4.4.

- List of all members, including inherited members

### Public Functions

- QXmlNamespaceSupport ()
- ~QXmlNamespaceSupport ()
- void popContext ()
- QString prefix ( const QString & uri ) const
- QStringList prefixes () const
- QStringList prefixes ( const QString & uri ) const
- void processName ( const QString & qname, bool isAttribute, QString & nsuri, QString & localname ) const
- void pushContext ()
- void reset ()
- void setPrefix ( const QString & pre, const QString & uri )
- void splitName ( const QString & qname, QString & prefix, QString & localname ) const
- QString uri ( const QString & prefix ) const

## Detailed Description

The QXmlNamespaceSupport class is a helper class for XML readers which want to include namespace support.

You can set the prefix for the current namespace with setPrefix(), and get the list of current prefixes (or those for a given URI) with prefixes(). The namespace URI is available from uri(). Use pushContext() to start a new namespace context, and popContext() to return to the previous namespace context. Use splitName() or processName() to split a name into its prefix and local name.

See also Namespace Support via Features.

## Member Function Documentation

### QXmlNamespaceSupport::QXmlNamespaceSupport ()

Constructs a QXmlNamespaceSupport.

### QXmlNamespaceSupport::~QXmlNamespaceSupport ()

Destroys a QXmlNamespaceSupport.

### void QXmlNamespaceSupport::popContext ()

Reverts to the previous namespace context.

Normally, you should pop the context at the end of each XML element. After popping the context, all namespace prefix mappings that were previously in force are restored.

See also pushContext().

### QString QXmlNamespaceSupport::prefix ( const QString & uri ) const

Returns one of the prefixes mapped to the namespace URI uri.

If more than one prefix is currently mapped to the same URI, this function makes an arbitrary selection; if you want all of the prefixes, use prefixes() instead.

Note: to check for a default prefix, use the uri() function with an argument of "".

See also setPrefix().

### QStringList QXmlNamespaceSupport::prefixes () const

Returns a list of all the prefixes currently declared.

If there is a default prefix, this function does not return it in the list; check for the default prefix using uri() with an argument of "".

### QStringList QXmlNamespaceSupport::prefixes ( const QString & uri ) const

This is an overloaded member function, provided for convenience.

Returns a list of all prefixes currently declared for the namespace URI uri.

The "xml:" prefix is included. If you only want one prefix that is mapped to the namespace URI, and you don't care which one you get, use the prefix() function instead.

Note: The empty (default) prefix is never included in this list; to check for the presence of a default namespace, call uri() with "" as the argument.

### void QXmlNamespaceSupport::processName ( const QString & qname, bool isAttribute, QString & nsuri, QString & localname ) const

Processes a raw XML 1.0 name in the current context by removing the prefix and looking it up among the prefixes currently declared.

qname is the raw XML 1.0 name to be processed. isAttribute is true if the name is an attribute name.

This function stores the namespace URI in nsuri (which will be set to an empty string if the raw name has an undeclared prefix), and stores the local name (without prefix) in localname (which will be set to an empty string if no namespace is in use).

Note that attribute names are processed differently than element names: an unprefixed element name gets the default namespace (if any), while an unprefixed attribute name does not.

### void QXmlNamespaceSupport::pushContext ()

Starts a new namespace context.

Normally, you should push a new context at the beginning of each XML element: the new context automatically inherits the declarations of its parent context, and it also keeps track of which declarations were made within this context.

See also popContext().

### void QXmlNamespaceSupport::reset ()

Resets this namespace support object ready for reuse.

### void QXmlNamespaceSupport::setPrefix ( const QString & pre, const QString & uri )

This function declares a prefix pre in the current namespace context to be the namespace URI uri. The prefix remains in force until this context is popped, unless it is shadowed in a descendant context.

Note that there is an asymmetry in this library. prefix() does not return the default "" prefix, even if you have declared one; to check for a default prefix, you must look it up explicitly using uri(). This asymmetry exists to make it easier to look up prefixes for attribute names, where the default prefix is not allowed.

See also prefix().

### void QXmlNamespaceSupport::splitName ( const QString & qname, QString & prefix, QString & localname ) const

Splits the name qname at the ':' and returns the prefix in prefix and the local name in localname.

See also processName().

### QString QXmlNamespaceSupport::uri ( const QString & prefix ) const

Looks up the prefix prefix in the current context and returns the currently-mapped namespace URI. Use the empty string ("") for the default namespace.