CODEWITHSUNDEEP
androidxml
Luke Vo
Luke Vo

Reputation: 20658

Need help explain the basic of XML Parsing

I have read many articles about XML parsing in Android. However, all of them are just code without any explaination. I'm new to Android (and even Java), however, I have been with .NET for a long time. So please explain me some classes:

SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();

What do they do?

xr.parse(new InputSource(sourceUrl.openStream()));

This parse a XML file from the Internet. How can I parse a XML file in res/raw? And even with a XML file in SD Card?

Is there any class like XMLDocument in .NET? And how can I write XML file into SD Card?

Thank you.

Upvotes: 0

Views: 507

Answers (2)

wired00
wired00

Reputation: 14438

what might help you out to know is that you can easily also pass a standard string containing XML into the XML Handler intsead of providing a input stream from URL. This might help where you wanted to open some XML string from SD card or any file etc.

you can simply do something like this:

xr.parse(new InputSource(Utils.stringToInputStream(xmlString)));

in my Utils.java file class simply method to convert string to InputStream:

public static InputStream stringToInputStream(String str) throws UnsupportedEncodingException {
  return new ByteArrayInputStream(str.getBytes("UTF-8"));
}

Also i know you say you've read many tutorials but i found this tutorial very helpful.

Hope that helps

Upvotes: 0

Heiko Rupp
Heiko Rupp

Reputation: 30934

The first three lines just set up an XML parser. The variant of parser is a stream parser, that does not need the full input as a tree in memory (that would be a dom parser), but which reads the xml data as it streams by.

Do read stuff from the assets folder you could use that code:

  AssetManager assetManager = context.getAssets();
        try {
            InputStream is = assetManager.open("1.xml");
            board = new Board();
            board.loadFromXmlInputStream(is);
            is.close();

where board.loadFromXmlInputStream(is); internally calls your above 3 lines of code and then xr.parse(new InputSource(is)

See e.g. SampleView for the above lines and the Board.

Note that your code above will not be enough to process the XML - you also need some callbacks (like the ones shown in the Board class).

As an alternative you can also use a DOM parser, that creates a tree representation of the XML in memory that you can then walk.

Upvotes: 1

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