QXmlStreamWriter 类提供采用简单流化 API 的 XML 写入器。 更多...
| 头： | #include <QXmlStreamWriter> |
| qmake: | QT += core |
| Since: | Qt 4.3 |
该类在 Qt 4.3 引入。
注意： 此类的所有函数 可重入 .
| QXmlStreamWriter (QString * string ) | |
| QXmlStreamWriter (QByteArray * array ) | |
| QXmlStreamWriter (QIODevice * device ) | |
| QXmlStreamWriter () | |
| ~QXmlStreamWriter () | |
| bool | autoFormatting () const |
| int | autoFormattingIndent () const |
| QTextCodec * | codec () const |
| QIODevice * | device () const |
| bool | hasError () const |
| void | setAutoFormatting (bool enable ) |
| void | setAutoFormattingIndent (int spacesOrTabs ) |
| void | setCodec (QTextCodec * codec ) |
| void | setCodec (const char * codecName ) |
| void | setDevice (QIODevice * device ) |
| void | writeAttribute (const QString & namespaceUri , const QString & name , const QString & value ) |
| void | writeAttribute (const QString & qualifiedName , const QString & value ) |
| void | writeAttribute (const QXmlStreamAttribute & 属性 ) |
| void | writeAttributes (const QXmlStreamAttributes & 属性 ) |
| void | writeCDATA (const QString & text ) |
| void | writeCharacters (const QString & text ) |
| void | writeComment (const QString & text ) |
| void | writeCurrentToken (const QXmlStreamReader & reader ) |
| void | writeDTD (const QString & dtd ) |
| void | writeDefaultNamespace (const QString & namespaceUri ) |
| void | writeEmptyElement (const QString & namespaceUri , const QString & name ) |
| void | writeEmptyElement (const QString & qualifiedName ) |
| void | writeEndDocument () |
| void | writeEndElement () |
| void | writeEntityReference (const QString & name ) |
| void | writeNamespace (const QString & namespaceUri , const QString & prefix = QString()) |
| void | writeProcessingInstruction (const QString & target , const QString & data = QString()) |
| void | writeStartDocument (const QString & version ) |
| void | writeStartDocument () |
| void | writeStartDocument (const QString & version , bool standalone ) |
| void | writeStartElement (const QString & namespaceUri , const QString & name ) |
| void | writeStartElement (const QString & qualifiedName ) |
| void | writeTextElement (const QString & namespaceUri , const QString & name , const QString & text ) |
| void | writeTextElement (const QString & qualifiedName , const QString & text ) |
QXmlStreamWriter 搭档 QXmlStreamReader 为写入 XML。像其相关类，它操作 QIODevice 指定采用 setDevice ()。API 简单明了：为想要编写每个 XML 令牌或事件，写入器提供专用功能。
开始文档采用 writeStartDocument () 和结束它采用 writeEndDocument (). This will implicitly close all remaining open tags.
Element tags are opened with writeStartElement () followed by writeAttribute () 或 writeAttributes (), element content, and then writeEndElement (). A shorter form writeEmptyElement () can be used to write empty elements, followed by writeAttributes ().
Element content consists of either characters, entity references or nested elements. It is written with writeCharacters (), which also takes care of escaping all forbidden characters and character sequences, writeEntityReference (), or subsequent calls to writeStartElement (). A convenience method writeTextElement () can be used for writing terminal elements that contain nothing but text.
The following abridged code snippet shows the basic use of the class to write formatted XML with indentation:
QXmlStreamWriter stream(&output);
stream.setAutoFormatting(true);
stream.writeStartDocument();
...
stream.writeStartElement("bookmark");
stream.writeAttribute("href", "http://qt-project.org/");
stream.writeTextElement("title", "Qt Project");
stream.writeEndElement(); // bookmark
...
stream.writeEndDocument();
QXmlStreamWriter takes care of prefixing namespaces, all you have to do is specify the
namespaceUri
when writing elements or attributes. If you must conform to certain prefixes, you can force the writer to use them by declaring the namespaces manually with either
writeNamespace
() 或
writeDefaultNamespace
(). Alternatively, you can bypass the stream writer's namespace support and use overloaded methods that take a qualified name instead. The namespace
http://www.w3.org/XML/1998/namespace
is implicit and mapped to the prefix
xml
.
The stream writer can automatically format the generated XML data by adding line-breaks and indentation to empty sections between elements, making the XML data more readable for humans and easier to work with for most source code management systems. The feature can be turned on with the autoFormatting property, and customized with the autoFormattingIndent 特性。
Other functions are writeCDATA (), writeComment (), writeProcessingInstruction ()，和 writeDTD (). Chaining of XML streams is supported with writeCurrentToken ().
By default, QXmlStreamWriter encodes XML in UTF-8. Different encodings can be enforced using setCodec ().
If an error occurs while writing to the underlying device, hasError () starts returning true and subsequent writes are ignored.
The QXmlStream 书签范例 illustrates how to use a stream writer to write an XML bookmark file (XBEL) that was previously read in by a QXmlStreamReader .
The auto-formatting flag of the stream writer
This property controls whether or not the stream writer automatically formats the generated XML data. If enabled, the writer automatically adds line-breaks and indentation to empty sections between elements (ignorable whitespace). The main purpose of auto-formatting is to split the data into several lines, and to increase readability for a human reader. The indentation depth can be controlled through the autoFormattingIndent 特性。
默认情况下，自动格式化被禁用。
该特性在 Qt 4.4 引入。
访问函数：
| bool | autoFormatting () const |
| void | setAutoFormatting (bool enable ) |
This property holds the number of spaces or tabs used for indentation when auto-formatting is enabled. Positive numbers indicate spaces, negative numbers tabs.
默认缩进为 4。
该特性在 Qt 4.4 引入。
访问函数：
| int | autoFormattingIndent () const |
| void | setAutoFormattingIndent (int spacesOrTabs ) |
另请参阅 autoFormatting .
Constructs a stream writer that writes into string .
Note that when writing to QString , QXmlStreamWriter ignores the codec set with setCodec (). See that function for more information.
Constructs a stream writer that writes into array . This is the same as creating an xml writer that operates on a QBuffer device which in turn operates on array .
Constructs a stream writer that writes into device ;
构造流写入器。
另请参阅 setDevice ().
析构函数。
返回
true
if auto formatting is enabled, otherwise
false
.
注意： getter 函数对于特性 autoFormatting。
该函数在 Qt 4.4 引入。
另请参阅 setAutoFormatting ().
Returns the codec that is currently assigned to the stream.
另请参阅 setCodec ().
返回被当前设备关联的
QXmlStreamWriter
，或
nullptr
若没有设备被赋值。
另请参阅 setDevice ().
返回
true
若写入失败。
This can happen if the stream failed to write to the underlying device or if the data to be written contained invalid characters.
The error status is never reset. Writes happening after the error occurred may be ignored, even if the error condition is cleared.
启用自动格式化若
enable
is
true
，否则禁用它。
默认值为
false
.
注意： setter 函数对于特性 autoFormatting .
该函数在 Qt 4.4 引入。
另请参阅 autoFormatting ().
Sets the codec for this stream to codec . The codec is used for encoding any data that is written. By default, QXmlStreamWriter uses UTF-8.
The encoding information is stored in the initial xml tag which gets written when you call writeStartDocument (). Call this function before calling writeStartDocument ().
注意： When writing the XML to a QString , the codec information is ignored and the XML header will not include any encoding information, since all QStrings are UTF-16. If you later convert the QString to an 8-bit format, you must arrange for the encoding information to be transmitted out-of-band.
另请参阅 codec ().
Sets the codec for this stream to the
QTextCodec
为指定编码通过
codecName
。常见值对于
codecName
包括 ISO 8859-1、UTF-8 及 UTF-16。若编码无法识别，则什么都不发生。
注意： When writing the XML to a QString , the codec information is ignored and the XML header will not include any encoding information, since all QStrings are UTF-16. If you later convert the QString to an 8-bit format, you must arrange for the encoding information to be transmitted out-of-band.
另请参阅 QTextCodec::codecForName ().
把当前设备设为 device . If you want the stream to write into a QByteArray ，可以创建 QBuffer 设备。
另请参阅 device ().
Writes an attribute with name and value , prefixed for the specified namespaceUri . If the namespace has not been declared yet, QXmlStreamWriter will generate a namespace declaration for it.
This function can only be called after writeStartElement () before any content is written, or after writeEmptyElement ().
这是重载函数。
Writes an attribute with qualifiedName and value .
This function can only be called after writeStartElement () before any content is written, or after writeEmptyElement ().
这是重载函数。
写入 属性 .
This function can only be called after writeStartElement () before any content is written, or after writeEmptyElement ().
Writes the attribute vector 属性 . If a namespace referenced in an attribute not been declared yet, QXmlStreamWriter will generate a namespace declaration for it.
This function can only be called after writeStartElement () before any content is written, or after writeEmptyElement ().
另请参阅 writeAttribute () 和 writeNamespace ().
写入 text as CDATA section. If text contains the forbidden character sequence "]]>", it is split into different CDATA sections.
This function mainly exists for completeness. Normally you should not need use it, because writeCharacters () automatically escapes all non-content characters.
写入 text . The characters "<", "&", and """ are escaped as entity references "<", "&, and """. To avoid the forbidden sequence "]]>", ">" is also escaped as ">".
另请参阅 writeEntityReference ().
写入 text as XML comment, where text must not contain the forbidden sequence "--" or end with "-". Note that XML does not provide any way to escape "-" in a comment.
Writes the current state of the reader . All possible valid states are supported.
The purpose of this function is to support chained processing of XML data.
另请参阅 QXmlStreamReader::tokenType ().
Writes a DTD section. The dtd represents the entire doctypedecl production from the XML 1.0 specification.
Writes a default namespace declaration for namespaceUri .
若 writeStartElement () 或 writeEmptyElement () was called, the declaration applies to the current element; otherwise it applies to the next child element.
Note that the namespaces http://www.w3.org/XML/1998/namespace (bound to xmlns ) 和 http://www.w3.org/2000/xmlns/ (bound to xml ) by definition cannot be declared as default.
Writes an empty element with name , prefixed for the specified namespaceUri . If the namespace has not been declared, QXmlStreamWriter will generate a namespace declaration for it. Subsequent calls to writeAttribute () will add attributes to this element.
另请参阅 writeNamespace ().
这是重载函数。
Writes an empty element with qualified name qualifiedName . Subsequent calls to writeAttribute () will add attributes to this element.
Closes all remaining open start elements and writes a newline.
另请参阅 writeStartDocument ().
Closes the previous start element.
另请参阅 writeStartElement ().
Writes the entity reference name to the stream, as "& name ;".
Writes a namespace declaration for namespaceUri with prefix 。若 prefix is empty, QXmlStreamWriter assigns a unique prefix consisting of the letter 'n' followed by a number.
若 writeStartElement () 或 writeEmptyElement () was called, the declaration applies to the current element; otherwise it applies to the next child element.
Note that the prefix xml is both predefined and reserved for http://www.w3.org/XML/1998/namespace , which in turn cannot be bound to any other prefix. The prefix xmlns and its URI http://www.w3.org/2000/xmlns/ are used for the namespace mechanism itself and thus completely forbidden in declarations.
Writes an XML processing instruction with target and data ，其中 data must not contain the sequence "?>".
Writes a document start with the XML version number version .
另请参阅 writeEndDocument ().
这是重载函数。
Writes a document start with XML version number "1.0". This also writes the encoding information.
该函数在 Qt 4.5 引入。
另请参阅 writeEndDocument () 和 setCodec ().
Writes a document start with the XML version number version and a standalone attribute standalone .
该函数在 Qt 4.5 引入。
另请参阅 writeEndDocument ().
Writes a start element with name , prefixed for the specified namespaceUri . If the namespace has not been declared yet, QXmlStreamWriter will generate a namespace declaration for it. Subsequent calls to writeAttribute () will add attributes to this element.
另请参阅 writeNamespace (), writeEndElement ()，和 writeEmptyElement ().
这是重载函数。
Writes a start element with qualifiedName . Subsequent calls to writeAttribute () will add attributes to this element.
另请参阅 writeEndElement () 和 writeEmptyElement ().
Writes a text element with name , prefixed for the specified namespaceUri ，和 text . If the namespace has not been declared, QXmlStreamWriter will generate a namespace declaration for it.
This is a convenience function equivalent to:
writeStartElement(namespaceUri, name);
writeCharacters(text);
writeEndElement();
这是重载函数。
Writes a text element with qualifiedName and text .
This is a convenience function equivalent to:
writeStartElement(qualifiedName);
writeCharacters(text);
writeEndElement();