我正在尝试制作一个解析 RSS 提要的应用程序。我运行我的应用程序，但是虽然源链接 ( http://api.androidhive.info/music/music.xml ) 非常快，但数据的获取速度非常慢。
我需要我的应用程序快速响应。
我的应用程序代码：
package com.sta.map;
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.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.ListView;
import android.widget.TextView;
public class POSTS extends Activity {
static final String KEY_ARTIST = "artist";
static final String KEY_THUMB_URL = "thumb_url";
ListView list;
WbAdapter adapter;
static String URL = "http://api.androidhive.info/music/music.xml";
ProgressDialog pDialog;
ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.posts);
new ParseXMLTask().execute();
}
class ParseXMLTask extends AsyncTask<String, String, String> {
protected void onPreExecute() {
// Showing progress dialog before sending http request
pDialog = new ProgressDialog(POSTS.this);
pDialog.setMessage("Please wait..");
pDialog.setIndeterminate(true);
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected String doInBackground(String... unused) {
XMLParser parser = new XMLParser();
String xml = parser.getXmlFromUrl(url); // getting XML from URL
return xml;
}
@Override
protected void onPostExecute(String result) {
pDialog.dismiss();
XMLParser parser = new XMLParser();
Document doc = parser.getDomElement(result); // getting DOM element
NodeList nl = doc.getElementsByTagName("song");
// looping through all song nodes <song>
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_ARTIST, parser.getValue(e, KEY_ARTIST));
map.put(KEY_THUMB_URL, parser.getValue(e, KEY_THUMB_URL));
// adding HashList to ArrayList
songsList.add(map);
}
list=(ListView)findViewById(R.id.list);
adapter= new WbAdapter(POSTS.this, songsList);
list.setAdapter(adapter);
}
}
}
XMLParser班级 ：
package com.sta.map;
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.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import android.util.Log;
public class XMLParser {
// constructor
public XMLParser() {
}
/**
* Getting XML from URL making HTTP request
* @param url string
* */
public String getXmlFromUrl(String url) {
String xml = null;
try {
// defaultHttpClient
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 getDomElement(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;
}
/** Getting node value
* @param elem 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 "";
}
/**
* Getting node value
* @param Element node
* @param key string
* */
public String getValue(Element item, String str) {
NodeList n = item.getElementsByTagName(str);
return this.getElementValue(n.item(0));
}
}
编辑1：在清单中我发现了这段代码：
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="16" />
我删除了这部分android:targetSdkVersion="16"，解析变得非常快
为什么 ？？