Receive notification of ignorable whitespace in element content. Application writers may override this method to take specific actions for each chunk of ignorable whitespace (such as adding data to a node or buffer, or printing it to a file). This method implements the SAX default behaviour: application writers can override it in a subclass to do special translations such as catalog lookups or URI redirection. Receive notification of the beginning of the document. Application writers may override this method in a subclass to take specific actions at the beginning of a document (such as allocating the root node of a tree or creating an output file). Receive notification of the start of a Namespace mapping. Application writers may override this method in a subclass to take specific actions at the start of each Namespace prefix scope (such as storing the prefix mapping). Application writers may override this method in a subclass to take specific actions for each warning, such as inserting the message in a log file or printing it to the console. This class parses a XML file containing employee details and stores in a list as an employee object. So if the application does not generate an exception, then the default error-event handler generates one.
Receive notification of an unparsed entity declaration. Application writers may override this method in a subclass to keep track of the unparsed entities declared in a document. public void start Element(String uri, String local Name, String q Name, Attributes attributes) throws SAXException public void characters(char ch, int start, int length) throws SAXException public void end Element(String uri, String local Name, String q Name) throws SAXException 就上面的代码分析，实现一个Content Handler一般要一下几个步骤： 1、声明一个类，继承Default Handler。Default Handler是一个基类，这个类里面简单实现了一个Content Handler。我们只需要重写里面的方法即可。 2、重写 start Document() 和 end Document()，一般解析将正式解析之前的一些初始化工资放到start Document()里面，收尾的工作放到end Document()里面。 3、重写start Element(), XML解析器遇到XML里面的tag时就会调用这个函数。经常在这个函数内是通过local Name俩进行判断而操作一些数据。 4、重写characters()方法，这是一个回调方法。解析器执行完start Element()后，解析完节点的内容后就会执行这个方法，并且参数ch就是节点的内容。这个例子里我们根据currentstate的不同，来判断当前那个tag的内容，并放到合适的实体类中。 5、重写end Element()方法，这个方法与start Element()相对应，解析完一个tag节点后，执行这个方法。再找个例子中，如果解析一个item结束，就将RSSIiem添加到RSSFeed中。 最后我们实现一个activity来展现解析的结果： To parse an XML in Android, you can use DOM and SAX parser API provided by Java platform. Create a new Java class “SAXXMLParser.java” in package “com.theopentutorials.android.xml” and copy the following code.package com.theopentutorials.android.xml; import But for nonfatal errors and warnings, exceptions are never generated by the default error handler, and no messages are displayed.
As stated at the beginning of this lesson, after you have downloaded and installed the sources of the JAXP API from the , the sample program and the associated files needed to run it are found in the following locations.
A nonfatal error occurs when an XML document fails a validity constraint.
In addition to these two parsers, Android provides Xml Pull Parser which is similar to St AX parser and is also the recommended parser to use in Android.package com.theopentutorials.android.xml; import As shown in , the application's event handling methods throw can be constructed using a message, another exception, or both.
To create an entity reference, you surround the entity name with an ampersand and a semicolon: Once parsed, this text would be displayed as follows: CDATA sections may occur anywhere character data may occur; they are used to escape blocks of text containing characters which would otherwise be recognized as markup. The existence of CDATA makes the proper echoing of XML a bit tricky.
This property names a class that is a concrete subclass of this abstract class. The following code sets up the parser and gets it started: method defined in .
If no property is defined, a platform default will be used. Application writers may override this method in a subclass to take specific actions at the end of each element (such as finalising a tree node or writing output to a file). Log; public class SAXXMLParser package com.theopentutorials.android.activities; import You could start using your parser now, but it is safer to implement some error handling.
If the parser finds that the document is not valid, then an error event is generated.