android - 从 Android RSS 阅读器中的描述节点问题中获取数据

Question

我一直在开发一个 Android RSS 阅读器应用程序，但在从描述节点获取 HTML 内容时遇到了问题。

我尝试从以下 XML 中获取数据。

        <description>
    <p><a href="http://in.news.yahoo.com/search-arizona-girl-6-turns-back-her-tucson-021230195.html">
   <img src="http://l.yimg.com/bt/api/res/1.2/t8X__zdk6shihpWw0Nenfw--/YXBwaWQ9eW5ld3M7Zmk9ZmlsbDtoPTg2O3B4b2ZmPTUwO3B5b2ZmPTA7cT04NTt3PTEzMA--/http://media.zenfs.com/en_us/News/Reuters/2012-04-24T021230Z_1_CDEE83N064W00_RTROPTP_2_USA-MISSING-ARIZONA.JPG" 
width="130" height="86" alt="Handout photo of Isabel Mercedes Celis" align="left" title="Handout photo of Isabel Mercedes Celis" border="0" />

</a>
      TUCSON, Arizona (Reuters) - The search for a missing 6-year-old Arizona girl who a               authorities said may have been snatched from her bedroom in Tucson entered its third day on  Monday as search dogs shifted investigators' attention back to the child's home. The  parents of first-grader Isabel Mercedes Celis told detectives she was last seen on Friday  night when they tucked her into bed, and was found to have vanished when a family member   entered her room the next morning to awaken her, police said. ...
    </p>
  <br clear="all"/>
 </description>

获取数据时显示空白。我将我的整个代码粘贴在下面..

我正在从这个网址获取 Rss: http://in.news.yahoo.com/rss/crime

RSSActivity.java

package com.satyampv.dsta;


import java.util.ArrayList;
import java.util.HashMap;

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Element;


import android.app.ListActivity;
import android.os.Bundle;

import android.text.util.Linkify;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.SimpleAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class AstroRssActivity extends ListActivity {
    /** Called when the activity is first created. */
    //static final String URL = "http://findyourfate.com/rss/dailyhoroscope-feed.asp?sign=Taurus";

    //static final String URL = "http://my.horoscope.com/astrology/daily-horoscopes-rss.html";
    static final String URL = "http://in.news.yahoo.com/rss/crime";
    // XML node keys
    static final String KEY_ITEM = "item"; // parent node
    static final String KEY_TITLE = "title";
    static final String KEY_DESC = "description";
    static final String KEY_LINK = "link";



    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        ArrayList<HashMap<String, String>> menuItems = new ArrayList<HashMap<String, String>>();

        XMLParser parser = new XMLParser();
        String xml = parser.getXMLFromURL(URL);// getting XML
        Document doc = parser.getDocumentElement(xml);// getting DOM element

        NodeList nl = doc.getElementsByTagName(KEY_ITEM);
        // looping through all item nodes <item>
        for (int i = 0; i < nl.getLength(); i++) {
            // creating new HashMap
            HashMap<String, String> map = new HashMap<String, String>();
            Element e = (Element) nl.item(i);

            // adding each child node to HashMap key => value

            map.put(KEY_TITLE, parser.getValue(e, KEY_TITLE));
            map.put(KEY_DESC, parser.getValue(e, KEY_DESC));
            map.put(KEY_LINK,parser.getValue(e, KEY_LINK));


            // adding HashList to ArrayList
            menuItems.add(map);
        }

        // Adding menuItems to ListView
        ListAdapter adapter = new SimpleAdapter(this, menuItems,
                R.layout.list_item,
                new String[] { KEY_TITLE, KEY_DESC, KEY_LINK }, new int[] {
                        R.id.name, R.id.desciption, R.id.link });

        setListAdapter(adapter);

XMLParser.java

package com.satyampv.dsta;

import java.io.IOException;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Element;

import org.xml.sax.InputSource;
import org.xml.sax.SAXException;


import android.util.Log;

public class XMLParser {


    public XMLParser() {

    }

    public String getXMLFromURL(String url) {

        String xml = null;

        try {
            // Default HTTP Client

            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();

            xml = EntityUtils.toString(httpEntity);

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        // return XML
        return xml;
    }

    // Getting xml Dom element @param xml String

    public Document getDocumentElement(String xml) {

        Document doc = null;
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

        try {

            DocumentBuilder db = dbf.newDocumentBuilder();

            InputSource is = new InputSource();
            is.setCharacterStream(new StringReader(xml));
            doc = db.parse(is);
        } catch (ParserConfigurationException e) {
            Log.e("Error", e.getMessage());
            return null;
        } catch (SAXException e) {

            Log.e("Error", e.getMessage());
            return null;

        } catch (IOException e) {
            Log.e("Error", e.getMessage());
            return null;
        }

        return doc;
    }


    public String getValue(Element item,String str){
        NodeList n = item.getElementsByTagName(str);
        return this.getElementValue(n.item(0));
    }
    // Getting node Value
    // @params ele element

    public final String getElementValue(Node elem) {
        Node child;

        if (elem != null) {

            if (elem.hasChildNodes()) {
                for (child = elem.getFirstChild(); child != null; child = child
                        .getNextSibling())
                {
                    if (child.getNodeType() == Node.TEXT_NODE) {
                        return child.getNodeValue();
                    }
                }

            }
        }

        return "";

    }
}

Answer 1

如果您的描述节点包含 HTML 标签，则它不包含任何 TEXT_NODE 类型的子节点，这就是它返回空的原因。

检查您的描述节点中的子节点是什么类型，以了解如何处理这些节点。

编辑

一种解决方案是使用 getTextContent ( http://docs.oracle.com/javase/1.5.0/docs/api/org/w3c/dom/Node.html#getTextContent%28%29 ) 而不是搜索文本节点。而不是:

if (elem.hasChildNodes()) {
    for (child = elem.getFirstChild(); child != null; child = child.getNextSibling()) {
        if (child.getNodeType() == Node.TEXT_NODE) {
            return child.getNodeValue();
        }
    }
}

你可以简单地去:

return elem.getTextContent();

稍后，您可以使用 Html.fromHtml() 解析 HTML:

HashMap<String, Spanned> map = new HashMap<String, Spanned>();

和

map.put(KEY_DESC, Html.fromHtml(parser.getValue(e, KEY_DESC)));

(参见 http://developer.android.com/reference/android/text/Html.html#fromHtml%28java.lang.String%29)

编辑2

并替换

ArrayList<HashMap<String, String>> menuItems = new ArrayList<HashMap<String, String>>();

与

ArrayList<HashMap<String, Spanned>> menuItems = new ArrayList<HashMap<String, Spanned>>();

此外，我认为 SimpleAdapter 需要 TextView 的字符串，因此您可能需要一个 ViewBinder 来将 Spanned 放入 TextView:

SimpleAdapter adapter = new SimpleAdapter(...);
adapter.setViewBinder(new SimpleAdapter.ViewBinder() {
    public boolean setViewValue(View view, Object data, String textRepresentation) {
        if (data instanceof Spanned && view instanceof TextView) {
            ((TextView) view).setText((Spanned) data));
        }
    }
}