Android 理解XmlPullParser示例

下午好

我正在学习Android开发者关于解析XML数据的课程。这一课我几乎都懂，但有一句话我想不通

但首先是示例：示例解析来自Stackoverflow的提要。但首先是提要：Stackoverflow提要中的每个帖子都显示为一个，每个帖子都有嵌套的标记

<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom" xmlns:creativeCommons="http://backend.userland.com/creativeCommonsRssModule" ...">
<title type="text">newest questions tagged android - Stack Overflow</title>
...
    <entry>
    ...
    </entry>
    <entry>
        <id>http://stackoverflow.com/q/9439999</id>
        <re:rank scheme="http://stackoverflow.com">0</re:rank>
        <title type="text">Where is my data file?</title>
        <category scheme="http://stackoverflow.com/feeds/tag?tagnames=android&sort=newest/tags" term="android"/>
        <category scheme="http://stackoverflow.com/feeds/tag?tagnames=android&sort=newest/tags" term="file"/>
        <author>
            <name>cliff2310</name>
            <uri>http://stackoverflow.com/users/1128925</uri>
        </author>
        <link rel="alternate" href="http://stackoverflow.com/questions/9439999/where-is-my-data-file" />
        <published>2012-02-25T00:30:54Z</published>
        <updated>2012-02-25T00:30:54Z</updated>
        <summary type="html">
            <p>I have an Application that requires a data file...</p>

        </summary>
    </entry>
    <entry>
    ...
    </entry>
...
</feed>

continue
表示“继续循环的下一次迭代”。因此，
if
语句的意思是“如果这个项目不有趣，试试下一个”
package com.mo.xmlpullparsersample;

import android.util.Xml;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class StackOverflowParser {
    // We are not using namespaces (i.e the fully qualified names) just the raw names
    private static final String ns = null;

    public List parse(InputStream in) throws XmlPullParserException, IOException {
        try {
            XmlPullParser parser = Xml.newPullParser();
            parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
            // Specify the input stream and input encoding - which is false - so it
            // will use XM: 1.0 endcoding by default)
            parser.setInput(in, null);
            // Move the parser to the next available tag
            parser.nextTag();
            return readFeed(parser);
        } finally {
            in.close();
        }
    }

    private List readFeed(XmlPullParser parser) throws XmlPullParserException, IOException {
        List entries = new ArrayList();


        // Test if the parser is where we require it to be - i.e the current event should be a
        // start-tag whose name is feed - i.e <feed>=. Stackoverflow's feed's first event is <feed>.
        // If the test fails then an exception is thrown.
        parser.require(XmlPullParser.START_TAG, ns, "feed");

        // While the parser has not reached the corresponding end-tag - i.e </feed>
        while (parser.next() != XmlPullParser.END_TAG) {
            if (parser.getEventType() != XmlPullParser.START_TAG) {
                continue;
            }
            // parser.getName() returns the name of the current tag for start-tag or end-tag events
             String name = parser.getName();
             // tests if the name = "entry" if yes, then read the entry.
            if (name.equals("entry")) {
                entries.add(readEntry(parser));
            } else {
                skip(parser);
            }
        }
        return entries;
    }
}