一. 前言

1. 了解 XmlResourceParser

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XmlResourceParser extends XmlPullParser

在Android中一般使用 XmlResourceParser，解析的Xml文件需要放在 Res文件夹下面的 xml文件夹 中。

2. 常用的方法

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/**
 * Returns the type of the current event (START_TAG, END_TAG, TEXT, etc.)
 *
 * @see #next()
 * @see #nextToken()
 */
int getEventType() throws XmlPullParserException;
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/**
 * This array can be used to convert the event type integer constants
 * such as START_TAG or TEXT to
 * to a string. For example, the value of TYPES[START_TAG] is
 * the string "START_TAG".
 *
 * This array is intended for diagnostic output only. Relying
 * on the contents of the array may be dangerous since malicious
 * applications may alter the array, although it is final, due
 * to limitations of the Java language.
 */
 String [] TYPES = {
      "START_DOCUMENT",
      "END_DOCUMENT",
      "START_TAG",
      "END_TAG",
      "TEXT",
      "CDSECT",
      "ENTITY_REF",
      "IGNORABLE_WHITESPACE",
      "PROCESSING_INSTRUCTION",
      "COMMENT",
      "DOCDECL"
 };

int START_DOCUMENT = 0;
int END_DOCUMENT = 1;
int START_TAG = 2;
int END_TAG = 3;
int TEXT = 4;
int CDSECT = 5;
int ENTITY_REF = 6;
int IGNORABLE_WHITESPACE = 7;
int PROCESSING_INSTRUCTION = 8;
int COMMENT = 9;
int DOCDECL = 10;
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/**
 * For START_TAG or END_TAG events, the (local) name of the current
 * element is returned when namespaces are enabled. When namespace
 * processing is disabled, the raw name is returned.
 * For ENTITY_REF events, the entity name is returned.
 * If the current event is not START_TAG, END_TAG, or ENTITY_REF,
 * null is returned.
 * <p><b>Please note:</b> To reconstruct the raw element name
 *  when namespaces are enabled and the prefix is not null,
 * you will need to  add the prefix and a colon to localName..
 *
 */
String getName();
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/**
 * Returns the given attributes value.
 * Throws an IndexOutOfBoundsException if the index is out of range
 * or current event type is not START_TAG.
 *
 * <p><strong>NOTE:</strong> attribute value must be normalized
 * (including entity replacement text if PROCESS_DOCDECL is false) as described in
 * <a href="http://www.w3.org/TR/REC-xml#AVNormalize">XML 1.0 section
 * 3.3.3 Attribute-Value Normalization</a>
 *
 * @see #defineEntityReplacementText
 *
 * @param index zero-based index of attribute
 * @return value of attribute (null is never returned)
 */
String getAttributeValue(int index);


/**
 * Returns the attributes value identified by namespace URI and namespace localName.
 * If namespaces are disabled namespace must be null.
 * If current event type is not START_TAG then IndexOutOfBoundsException will be thrown.
 *
 * <p><strong>NOTE:</strong> attribute value must be normalized
 * (including entity replacement text if PROCESS_DOCDECL is false) as described in
 * <a href="http://www.w3.org/TR/REC-xml#AVNormalize">XML 1.0 section
 * 3.3.3 Attribute-Value Normalization</a>
 *
 * @see #defineEntityReplacementText
 *
 * @param namespace Namespace of the attribute if namespaces are enabled otherwise must be null
 * @param name If namespaces enabled local name of attribute otherwise just attribute name
 * @return value of attribute or null if attribute with given name does not exist
 */
String getAttributeValue(String namespace, String name);
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/**
 * 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.
 * After calling this function successfully parser will be positioned on END_TAG.
 *
 * <p>The motivation for this function is to allow to parse consistently both
 * empty elements and elements that has non empty content, for example for input: <ol>
 * <li>&lt;tag&gt;foo&lt;/tag&gt;
 * <li>&lt;tag&gt;&lt;/tag&gt; (which is equivalent to &lt;tag/&gt;
 * both input can be parsed with the same code:
 * <pre>
 *   p.nextTag()
 *   p.requireEvent(p.START_TAG, "", "tag");
 *   String content = p.nextText();
 *   p.requireEvent(p.END_TAG, "", "tag");
 * </pre>
 * This function together with nextTag make it very easy to parse XML that has
 * no mixed content.
 *
 *
 * <p>Essentially it does this
 * <pre>
 *  if(getEventType() != START_TAG) {
 *     throw new XmlPullParserException(
 *       "parser must be on START_TAG to read next text", this, null);
 *  }
 *  int eventType = next();
 *  if(eventType == TEXT) {
 *     String result = getText();
 *     eventType = next();
 *     if(eventType != END_TAG) {
 *       throw new XmlPullParserException(
 *          "event TEXT it must be immediately followed by END_TAG", this, null);
 *      }
 *      return result;
 *  } else if(eventType == END_TAG) {
 *     return "";
 *  } else {
 *     throw new XmlPullParserException(
 *       "parser must be on START_TAG or TEXT to read text", this, null);
 *  }
 * </pre>
 *
 * <p><strong>Warning:</strong> Prior to API level 14, the pull parser returned by {@code
 * android.util.Xml} did not always advance to the END_TAG event when this method was called.
 * Work around by using manually advancing after calls to nextText(): <pre>
 *  String text = xpp.nextText();
 *  if (xpp.getEventType() != XmlPullParser.END_TAG) {
 *      xpp.next();
 *  }
 * </pre>
 */
String nextText() throws XmlPullParserException, IOException;
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/**
 * Get next parsing event - element content will be coalesced and only one
 * TEXT event must be returned for whole element content
 * (comments and processing instructions will be ignored and entity references
 * must be expanded or exception must be thrown if entity reference can not be expanded).
 * If element content is empty (content is "") then no TEXT event will be reported.
 *
 * <p><b>NOTE:</b> empty element (such as &lt;tag/>) will be reported
 *  with  two separate events: START_TAG, END_TAG - it must be so to preserve
 *   parsing equivalency of empty element to &lt;tag>&lt;/tag>.
 *  (see isEmptyElementTag ())
 *
 * @see #isEmptyElementTag
 * @see #START_TAG
 * @see #TEXT
 * @see #END_TAG
 * @see #END_DOCUMENT
 */

int next() throws XmlPullParserException, IOException;

二. 实际小例子

1. 待解析的Xml文件

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<?xml version="1.0" encoding="utf-8"?>
<web>
    <item id="0" url="https://www.baidu.com">百度</item>
    <item id="1" url="https://www.taobao.com">淘宝</item>
    <item id="2" url="https://www.qq.com">腾讯</item>
    <item id="3" url="https://www.aili.com">阿里巴巴</item>
    <item id="4" url="https://www.taobao.com">淘宝</item>
    <item id="5" url="https://www.wechat.com">微信</item>
    <item id="6" url="https://www.timi.com">天美</item>
    <item id="7" url="https://www.guangzi.com">光子</item>
    <item id="8" url="https://www.taoken.com">字节跳动</item>
    <item id="9" url="https://www.douyin.com">抖音</item>
</web>

2. Activity中的调用

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public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //PULL解析
        testPULLParse();
    }

    /**
     * PULL解析 使用XmlResourceParser 只有xml里面才可以读到
     */
    private void testPULLParse(){
        //存储解析的模型资源
        List<WebItem> webItems = null;

        //临时的模型类
        WebItem webItem = null;

        //获取Xml资源解析器
        XmlResourceParser xmlResourceParser = getResources().getXml(R.xml.test);

        //解析
        try {

            //事件类型
            int eventType = xmlResourceParser.getEventType();

            //只要还没有到文档结束的地方就继续解析
            while (xmlResourceParser.getEventType() != XmlResourceParser.END_DOCUMENT) {

                if (eventType == XmlResourceParser.START_DOCUMENT){

                    //如果当前的位置是文档的开始位置，实例化模型集合
                    webItems = new ArrayList<>();

                }else if (eventType == XmlResourceParser.START_TAG){

                    //如果当前位置是标签开始的位置

                    //如果当前标签是item，实例化WebItem，根据索引获得属性值
                    if (TextUtils.equals(xmlResourceParser.getName(),"item")){
                        webItem = new WebItem();

                        webItem.setId(Integer.parseInt(xmlResourceParser.getAttributeValue(0)));
                        webItem.setUrl(xmlResourceParser.getAttributeValue(1));
                        webItem.setContent(xmlResourceParser.nextText());

                        assert webItems != null;
                        webItems.add(webItem);
                    }
                }

                //继续解析
                eventType = xmlResourceParser.next();
            }
        } catch (XmlPullParserException e) {
            e.printStackTrace();

            Toast.makeText(this, "没有XMlPull解析器", Toast.LENGTH_SHORT).show();
        } catch (IOException e) {
            e.printStackTrace();

            Toast.makeText(this, "IO异常", Toast.LENGTH_SHORT).show();
        }

        //关闭
        xmlResourceParser.close();

        for (WebItem item : webItems) {
            //Toast.makeText(this, "id:"+item.getId()+" url:"+item.getUrl()+" content:"+item.getContent(), Toast.LENGTH_SHORT).show();
            //显示数据
            addToRootLayout((LinearLayout) findViewById(R.id.root),item);
        }
    }

    /**
     * 将WebItem显示到布局中
     * @param layout
     * @param webItem
     */
    private void addToRootLayout(LinearLayout layout, WebItem webItem){
        View inflate = LayoutInflater.from(this).inflate(R.layout.web_item_layout, null);
        TextView id_text = inflate.findViewById(R.id.id);
        TextView content_text = inflate.findViewById(R.id.content);
        TextView url_text = inflate.findViewById(R.id.url);

        id_text.setText(String.valueOf(webItem.getId()));
        content_text.setText(webItem.getContent());
        url_text.setText(webItem.getUrl());

        layout.addView(inflate);
    }
}

3. 运行结果

4. 源码地址

ParseXml

参考文章

Pull方式解析XML文件