我一直在试图弄清楚如何解决在尝试解析XML文件时我收到的错误。
这是我的MainActivity.java文件：
package com.example.android;
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.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xmlpull.v1.XmlPullParser;
import android.R.string;
import android.app.Activity;
import android.os.Bundle;
import android.renderscript.Element;
import android.util.Log;
import android.view.Menu;
import android.view.Window;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ImageView;
import android.widget.TextView;
public class MainActivity extends Activity {
String playerId,
playerPd,
playerType,
xml;
DefaultHttpClient httpClient;
HttpPost httpPost;
HttpResponse httpResponse;
HttpEntity httpEntity;
Document doc;
DocumentBuilderFactory dbf;
DocumentBuilder db;
InputSource inputSource;
NodeList n,
nl;
Node child;
XmlPullParser parser;
static final String URL = ".xml URL WITHELD";
static final String PLAYERS = "Players"; //parent node
static final String PLAYER_PD = "PlayerPD";
static final String PLAYER_TYPE = "PlayerType";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//Remove title bar
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public String getXmlFromUrl(String url){
xml = null;
try{
//defaultHttpClient
httpClient = new DefaultHttpClient();
httpPost = new HttpPost (url);
httpResponse = httpClient.execute(httpPost);
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;
}
public Document getDomElement(String xml){
doc = null;
dbf = DocumentBuilderFactory.newInstance();
try{
db = dbf.newDocumentBuilder();
inputSource = new InputSource();
inputSource.setCharacterStream(new StringReader (xml));
doc = db.parse(inputSource);
} 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 DOM
return doc;
}
public String getValue(Element item, String str){
n = ((Document) item).getElementsByTagName(str);
return this.getElementValue(n.item(0));
}
private final String getElementValue(Node elem){
// TODO Auto-generated method stub
if(elem.hasChildNodes()){
for(child = elem.getFirstChild(); child != null; child = child.getNextSibling()){
if(child.getNodeType() == Node.TEXT_NODE){
return child.getNodeValue();
}
}
}
return null;
}
public void parseXml(){
xml = parser.getXmlFromUrl(URL); //Getting XML
在这一行，第149行，我收到一条错误，上面写着“方法getXmlFromUrl（String）未定义类型XmlPullParser”
doc = parser.getDomElement(xml); //Getting DOM element
并且，在这一行，第150行，我收到一条错误，上面写着“方法getDomElement（String）未定义类型XmlPullParser”
nl = doc.getElementsByTagName(PLAYERS);
for (int i = 0; i < nl.getLength(); i++){
playerPd = parser.getValue(e, PLAYER_PD); //PlayerPD child value
此外，在这一行以及随后的一行，第155行和第156，我收到一条错误，上面写着“e无法解析为变量”
playerType = parser.getValue(e, PLAYER_TYPE); //Player Type child value
}
}
}
如果这有帮助，我试图解析的XML文件的布局是这样的：
-<Players>
-<Player id="">
<PlayerType></PlayerType>
</Player>
</Players>
任何帮助将不胜感激，并提前感谢。
答案 0 :(得分：3)
删除parser.
public void parseXml(){
xml = getXmlFromUrl(URL); //Getting XML
或者您可以创建一个类XMLParser并在新类中添加getXmlFromUrl函数
与其他功能类似
doc = getDomElement(xml); //Getting DOM element
你的线路155＆amp; 156不在完整的源代码中，所以我不确定上下文。
所以你已经提到了原始教程。本教程的含义是您需要创建一个包含名为XMLParser.java
XMLParser
public class XMLParser {
}
然后慢慢地向该类添加函数
public class XMLParser {
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;
}
}
等等，将其他函数添加到类中。然后，您可以使用MainActivity课程中的课程。
至于e cannot be resolved to a variable，网页上有一条缺失的行。
NodeList nl = doc.getElementsByTagName(KEY_ITEM);
// looping through all item nodes <item>
for (int i = 0; i < nl.getLength(); i++) {
Element e = (Element)nl.item(i); // >>> the missing line in the sample <<<
String name = parser.getValue(e, KEY_NAME); // name child value
String cost = parser.getValue(e, KEY_COST); // cost child value
String description = parser.getValue(e, KEY_DESC); // description child value
}