XML解析之Pull解析方式

最新推荐文章于 2024-03-19 20:23:14 发布

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最新推荐文章于 2024-03-19 20:23:14 发布

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分类专栏： android学习笔文章标签： xml PULL

本文链接：https://blog.youkuaiyun.com/allbule/article/details/52832422

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XML文件：

<apps>
    <app>
        <id>1</id>
        <name>gogle</name>
        <version>1.0</version>
    </app>
    <app>
        <id>2</id>
        <name>Chrome</name>
        <version>2.0</version>
    </app>
    <app>
        <id>3</id>
        <name>gogle PLAY</name>
        <version>3.0</version>
    </app>
</apps>

总体上的思路是这样的：
先获得一个XmlParser对象，然后从文档开始读到文档结束，然后获取每个标签后面的文本内容。

写代码之前先来介绍下几个函数以及标志。

public interface Xmlparser


int START_TAG       Returned from getEventType(), next(), nextToken() when a start tag was read.（大致意思是，当开始标签被读取由getEventType()，next(), nextToken()函数返回这个值。）

int END_TAG     Returned from getEventType(), next(), or nextToken() when an end tag was read.（当结束标签被读取由getEventType()，next(), nextToken()函数返回这个值。）

int END_DOCUMENT    Logical end of the xml document.（逻辑XML文件结尾）

abstract int    getEventType()
Returns the type of the current event (START_TAG, END_TAG, TEXT, etc.) （返回当前event类型）

abstract String getName() 
For START_TAG or END_TAG events, the (local) name of the current element is returned when namespaces are enabled.
（返回当前元素名）

abstract String nextText()
If current event is START_TAG then if next element is TEXT then element content is returned or if next event is END_TAG then empty string is returned, otherwise exception is thrown.（当前event是 START_TAG，返回后面的文本内容）

    private void parseXmlWithPull(String data){
        try {
            XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
            XmlPullParser pullParser=factory.newPullParser();
            pullParser.setInput(new StringReader(data));
            int eventType=pullParser.getEventType();
            String id="";
            String name="";
            String version="";
            while (eventType!=XmlPullParser.END_DOCUMENT){
                Log.d(TAG,"eventType is: "+eventType);
                Log.d(TAG,"event name is: "+pullParser.getName());
                switch (eventType){
                    case XmlPullParser.START_TAG: {
                        if (pullParser.getName().equals("id")) {
                            id = pullParser.nextText();
                        } else if (pullParser.getName().equals("name")) {
                            name = pullParser.nextText();
                        } else if (pullParser.getName().equals("version")) {
                            version = pullParser.nextText();
                        }
                        break;
                    }
                    case XmlPullParser.END_TAG:{
                        if (pullParser.getName().equals("app")){
                            Log.d(TAG, "id is:" + id);
                            Log.d(TAG, "name is:" + name);
                            Log.d(TAG, "version is:" + version);
                        }
                    }
                    default:
                        break;
                }

                eventType=pullParser.next();
            }
        }catch (Exception e){
            e.printStackTrace();
        }
    }

输出：

/*0： START_DOCUMENT
1：END_DOCUMENT
2：START_TAG 
3：END_TAG
4：TEXT
*/
10-16 08:19:10.910 968-1012/com.example.administrator.testforparse D/Test: eventType is: 0
10-16 08:19:10.910 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.910 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: event name is: apps
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: event name is: app
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: event name is: id
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: event name is: name
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.920 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: version
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 3
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: app
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: id is:1
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: name is:gogle
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: version is:1.0
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: app
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: id
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: name
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: version
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 3
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: app
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: id is:2
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: name is:Chrome
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: version is:2.0
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: app
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: id
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: name
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 2
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: event name is: version
10-16 08:19:10.930 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.950 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.950 968-1012/com.example.administrator.testforparse D/Test: eventType is: 3
10-16 08:19:10.950 968-1012/com.example.administrator.testforparse D/Test: event name is: app
10-16 08:19:10.950 968-1012/com.example.administrator.testforparse D/Test: id is:3
10-16 08:19:10.950 968-1012/com.example.administrator.testforparse D/Test: name is:gogle PLAY
10-16 08:19:10.950 968-1012/com.example.administrator.testforparse D/Test: version is:3.0
10-16 08:19:10.950 968-1012/com.example.administrator.testforparse D/Test: eventType is: 4
10-16 08:19:10.950 968-1012/com.example.administrator.testforparse D/Test: event name is: null
10-16 08:19:10.950 968-1012/com.example.administrator.testforparse D/Test: eventType is: 3
10-16 08:19:10.950 968-1012/com.example.administrator.testforparse D/Test: event name is: apps

如下图：
这里写图片描述

所以这里我们姑且可以这么理解：（个人理解，若有错误请帮忙指出，非常感谢）
getEventType获取每个元素的类型，如果是结点开始端（如< app>）的话，就返回 START TAG，当检测到START TAG 就去检测结点的名字，然后获取对应的文本，当检测到节点结尾返回END TAG（如< / app>）当然你也可以用getEventType检测判断是否为文本类型，如果是就获取他的文本内容。