# XML Parsing and Generation >![](../../public_sys-resources/icon-note.gif) **NOTE:** >The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version. ## Modules to Import ``` import xml from '@ohos.xml'; ``` ## Required Permissions None ## XmlSerializer ### constructor constructor\(buffer: ArrayBuffer | DataView, encoding?: string\) A constructor used to create an **XmlSerializer** instance. - Parameters

Name

Type

Mandatory

Description

buffer

ArrayBuffer | DataView

Yes

ArrayBuffer or DataView for storing the XML information to write.

encoding

string

No

Encoding format.
- Example ``` var arrayBuffer = new ArrayBuffer(1024); var bufView = new DataView(arrayBuffer); var thatSer = new xml.XmlSerializer(bufView); ``` ### setAttributes setAttributes\(name: string, value: string\): void Sets an attribute. - Parameters

Name

Type

Mandatory

Description

name

string

Yes

Key of the attribute.

value

string

Yes

Value of the attribute.
- Example ``` var thatSer = new xml.XmlSerializer(bufView); thatSer.setAttributes("importance", "high"); ``` ### addEmptyElement addEmptyElement\(name: string\): void Adds an empty element. - Parameters

Name

Type

Mandatory

Description

name

string

Yes

Name of the empty element to add.
- Example ``` var thatSer = new xml.XmlSerializer(bufView); thatSer.addEmptyElement("b"); // => ``` ### setDeclaration setDeclaration\(\): void Sets a declaration. - Example ``` var thatSer = new xml.XmlSerializer(bufView); thatSer.setDeclaration() // => ; ``` ### startElement startElement\(name: string\): void Writes the start tag based on the given element name. - Parameters

Name

Type

Mandatory

Description

name

string

Yes

Name of the element.
- Example ``` var arrayBuffer = new ArrayBuffer(1024); var thatSer = new xml.XmlSerializer(arrayBuffer); thatSer.startElement("notel"); thatSer.endElement();// => ''; ``` ### endElement endElement\(\): void Writes the end tag of the element. - Example ``` var thatSer = new xml.XmlSerializer(bufView); thatSer.setNamespace("h", "http://www.w3.org/TR/html4/"); thatSer.startElement("table"); thatSer.setAttributes("importance", "high"); thatSer.setText("Happy"); endElement(); // => Happy ``` ### setNamespace setNamespace\(prefix: string, namespace: string\): void Sets the namespace for an element tag. - Parameters

Name

Type

Mandatory

Description

prefix

string

Yes

Prefix of the element and its child elements.

namespace

string

Yes

Namespace to set.
- Example ``` var arrayBuffer = new ArrayBuffer(1024); var thatSer = new xml.XmlSerializer(arrayBuffer); thatSer.setDeclaration(); thatSer.setNamespace("h", "http://www.w3.org/TR/html4/"); thatSer.startElement("note"); thatSer.endElement();// = >'\r\n'; ``` ### setComment setComment\(text: string\): void Sets the comment. - Parameters

Name

Type

Mandatory

Description

text

string

Yes

Comment to set.
- Example ``` var arrayBuffer = new ArrayBuffer(1024); var thatSer = new xml.XmlSerializer(arrayBuffer); thatSer.startElement("note"); thatSer.setComment("Hi!"); thatSer.endElement(); // => '\r\n \r\n'; ``` ### setCDATA setCDATA\(text: string\): void Sets CDATA attributes. - Parameters

Name

Type

Mandatory

Description

text

string

Yes

CDATA attribute to set.
- Example ``` var arrayBuffer = new ArrayBuffer(1028); var thatSer = new xml.XmlSerializer(arrayBuffer); thatSer.setCDATA('root SYSTEM') // => ''; ``` ### setText setText\(text: string\): void Sets **Text**. - Parameters

Name

Type

Mandatory

Description

text

string

Yes

Content of the Text to set.
- Example ``` var arrayBuffer = new ArrayBuffer(1024); var thatSer = new xml.XmlSerializer(arrayBuffer); thatSer.startElement("note"); thatSer.setAttributes("importance", "high"); thatSer.setText("Happy1"); thatSer.endElement(); // => 'Happy1'; ``` ### setDocType setDocType\(text: string\): void Sets **DocType**. - Parameters

Name

Type

Mandatory

Description

text

string

Yes

Content of DocType to set.
- Example ``` var arrayBuffer = new ArrayBuffer(1024); var thatSer = new xml.XmlSerializer(arrayBuffer); thatSer.setDocType('root SYSTEM'); // => ''; ``` ## XmlPullParser ### XmlPullParser constructor\(buffer: ArrayBuffer | DataView, encoding?: string\) Creates and returns an **XmlPullParser** object. The **XmlPullParser** object passes two parameters. The first parameter is the memory of the **ArrayBuffer** or **DataView** type, and the second parameter is the file format \(UTF-8 by default\). - Parameters

Name

Type

Mandatory

Description

buffer

ArrayBuffer | DataView

Yes

ArrayBuffer or DataView that contains XML text information.

encoding

string

No

Encoding format. Only UTF-8 is supported.
- Example ``` var strXml = '' + '' + ' Happy' + ' Work' + ' Play' + ''; var arrayBuffer = new ArrayBuffer(strXml.length*2); var bufView = new Uint8Array(arrayBuffer); var strLen = strXml.length; for (var i = 0; i < strLen; ++i) { bufView[i] = strXml.charCodeAt(i);// Set the ArrayBuffer mode. } var that = new xml.XmlPullParser(arrayBuffer); ``` ### parse parse\(option: ParseOptions\): void Parses XML information. - Parameters

Name

Type

Mandatory

Description

option

ParseOptions

Yes

Options for controlling and obtaining the parsed information.
- Example ``` var strXml = '' + '' + ' Happy' + ' Work' + ' Play' + ''; var arrayBuffer = new ArrayBuffer(strXml.length*2); var bufView = new Uint8Array(arrayBuffer); var strLen = strXml.length; for (var i = 0; i < strLen; ++i) { bufView[i] = strXml.charCodeAt(i); } var that = new xml.XmlPullParser(arrayBuffer); var arrTag = {}; arrTag[0] = '132'; var i = 1; function func(key, value){ arrTag[i] = 'key:'+key+' value:'+ value.getDepth(); i++; return true; } var options = {supportDoctype:true, ignoreNameSpace:true, tokenValueCallbackFunction:func} that.parse(options); ``` ## ParseOptions Defines the XML parsing options.

Name

Type

Mandatory

Description

supportDoctype

boolean

No

Whether to ignore Doctype. The default value is false.

ignoreNameSpace

boolean

No

Whether to ignore Namespace. The default value is false.

tagValueCallbackFunction

(name: string, value: string)=> boolean

No

Callback used to return tagValue.

attributeValueCallbackFunction

(name: string, value: string)=> boolean

No

Callback used to return attributeValue.

tokenValueCallbackFunction

(eventType: EventType, value: ParseInfo)=> boolean

No

Callback used to return tokenValue.
## ParseInfo Provides methods to manage the parsed XML information. ### getColumnNumber getColumnNumber\(\): number Obtains the column line number, which starts from 1. - Return values

Type

Description

number

Column number obtained.
### getDepth getDepth\(\): number Obtains the depth of this element. - Return values

Type

Description

number

Depth obtained.
### getLineNumber getLineNumber\(\): number Obtains the current line number, starting from 1. - Return values

Type

Description

number

Line number obtained.
### getName getName\(\): string Obtains the name of this element. - Return values

Type

Description

string

Element name obtained.
### getNamespace getNamespace\(\): string Obtains the namespace of this element. - Return values

Type

Description

string

Namespace obtained.
### getPrefix getPrefix\(\): string Obtains the prefix of this element. - Return values

Type

Description

string

Element prefix obtained.
### getText getText\(\): string Obtains the text of the current event. - Return values

Type

Description

string

Text content obtained.
### isEmptyElementTag isEmptyElementTag\(\): boolean Checks whether the current element is empty. - Return values

Type

Description

boolean

Returns true if the element is empty; returns false otherwise.
### isWhitespace isWhitespace\(\): boolean Checks whether the current text event contains only whitespace characters. - Return values

Type

Description

boolean

Returns true if the text event contains only whitespace characters; returns false otherwise.
### getAttributeCount getAttributeCount\(\): number Obtains the number of attributes for the current start tag. - Return values

Type

Description

number

Number of attributes obtained.
## EventType Enumerates the events.

Name

Value

Description

START_DOCUMENT

0

Indicates a start document event.

END_DOCUMENT

1

Indicates an end document event.

START_TAG

2

Indicates a start tag event.

END_TAG

3

Indicates an end tag event.

TEXT

4

Indicates a text event.

CDSECT

5

Indicates a CDATA section event.

COMMENT

6

Indicates an XML comment event.

DOCDECL

7

Indicates an XML document type declaration event.

INSTRUCTION

8

Indicates an XML processing instruction event.

ENTITY_REFERENCE

9

Indicates an entity reference event.

WHITESPACE

10

Indicates a whitespace character event.