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我一直試圖在Android上使用SAX解析器來顯示一些xml，這是查詢到數據庫的結果。Android：處理程序返回空字符串解析與SAX解析器的XML
我從數據庫中得到正確的答案，但是當我想要解析xml並將內容轉儲到文本視圖中時，ExampleHandler（ParsedExampleDataSet）返回一個帶有空字符串的對象。我一直在試圖追蹤問題出在哪裏，但卻無法解決問題。
到目前爲止，我知道數據在字符方法中被正確解析，我設法將內容打印到日誌文件中，但是我不能在該點返回字符串。
我相信更多的程序員法的實驗可以很容易地解決這個問題：
我的XML文件是非常基本的，<body> blablablah </body>。
以下是文件：
package com.ignacio.BilingualSTT;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import android.util.Log;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.ByteArrayBuffer;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
public class PostAndGet extends Activity {
private static String Utterance = null;
TextView Title;
TextView Content;
private static final String TAG = "TextToSpeechDemo";
String text;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.en_results);
Title = (TextView)findViewById(R.id.A1_title);
Content= (TextView) findViewById(R.id.A1_content);
text = "";
Bundle b = this.getIntent().getExtras();
if (b !=null){
Utterance = b.getString("query");
}
postData(Utterance);
}
/**
* Handle the action of the Back button
*/
public void sendback(View v)
{
Intent Sendback=new Intent(this, EnglishRecognizer.class);
startActivity(Sendback);
}
/**
* Start HTTP Post call
*/
public void postData(String Utterance){
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://hcc.cs.clemson.edu/~ignm/ignacio/Android_QueryResults.php");
try {
// Add data to the HTTP Request data has to be named query since the PHP page in the server is expecting that name to run the query on the DB
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("query", Utterance));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// Execute HTTP Post Request and retrieve answer from PHP side.
HttpResponse response = httpclient.execute(httppost);
InputStream is = response.getEntity().getContent();
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(20);
int current = 0;
while((current = bis.read()) != -1){
baf.append((byte)current);
}
// Convert the Bytes read to a String and display it in the Title Container
text = new String(baf.toByteArray());
Title.setText(text);
//Send Text to
parseXML (text);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
Toast.makeText(this, "Error in the connection", Toast.LENGTH_SHORT).show();
} catch (IOException e) {
// TODO Auto-generated catch block
Toast.makeText(this,"IO Exception error", Toast.LENGTH_SHORT).show();
}
}
public void parseXML (String text){
String AnswerExt = text;
try {
/* Create a URL we want to load some xml-data from. */
URL url = new URL("http://hcc.cs.clemson.edu/~ignm/ignacio/"+AnswerExt.toString());
Log.i(TAG, url.toString());
/* Get a SAXParser from the SAXPArserFactory. */
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
/* Get the XMLReader of the SAXParser we created. */
XMLReader xr = sp.getXMLReader();
/* Create a new ContentHandler and apply it to the XML-Reader*/
ExampleHandler myExampleHandler = new ExampleHandler();
xr.setContentHandler(myExampleHandler);
/* Parse the xml-data from our URL. */
xr.parse(new InputSource(url.openStream()));
/* Parsing has finished. */
/* Our ExampleHandler now provides the parsed data to us. */
ParsedExampleDataSet parsedExampleDataSet = myExampleHandler.getParsedData();
/* Set the result to be displayed in our GUI. */
Content.setText(parsedExampleDataSet.getExtractedString());
} catch (Exception e) {
/* Display any Error to the GUI. */
Content.setText("Error: " + e.getMessage());
Log.e(TAG, "QueryError", e);
}
}
}
實例處理程序修改，以適應我的XML的解析。
package com.ignacio.BilingualSTT;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
public class ExampleHandler extends DefaultHandler{
// ===========================================================
// Fields
// ===========================================================
private boolean bodytag = false;
private static final String TAG = "TextToSpeechDemo";
public ParsedExampleDataSet myParsedExampleDataSet = new ParsedExampleDataSet();
public String myReturnString = null;
// ===========================================================
// Getter & Setter
// ===========================================================
public ParsedExampleDataSet getParsedData() {
return this.myParsedExampleDataSet;
}
// ===========================================================
// Methods
// ===========================================================
@Override
public void startDocument() throws SAXException {
this.myParsedExampleDataSet = new ParsedExampleDataSet();
}
@Override
public void endDocument() throws SAXException {
// Nothing to do
}
/** Gets be called on opening tags like:
* <tag>
* Can provide attribute(s), when xml was like:
* <tag attribute="attributeValue">*/
@Override
public void startElement(String namespaceURI, String localName,
String qName, Attributes atts) throws SAXException {
if (localName.equals("body")) {
this.bodytag = true;
}
}
/** Gets be called on closing tags like:
* </tag> */
@Override
public void endElement(String namespaceURI, String localName, String qName)
throws SAXException {
if (localName.equals("body")) {
this.bodytag = false;
}
}
/** Gets be called on the following structure:
* <tag>characters</tag> */
@Override
public void characters(char ch[], int start, int length) {
if(this.bodytag){
myParsedExampleDataSet.setExtractedString(new String(ch, start, length));
//String Temp = myParsedExampleDataSet.getExtractedString();
//Log.i(TAG, Temp);
}
}
}
ParsedExampleDataSet：
package com.ignacio.BilingualSTT;
public class ParsedExampleDataSet {
private String extractedString = "No content yet";
public String getExtractedString() {
return extractedString;
}
public void setExtractedString(String extractedString) {
this.extractedString = extractedString;
}
public String toString(){
return this.extractedString;
}
}
太謝謝你了！
如果代碼示例小得多（[SSCE]（http://sscce.org/）），讀取會更容易 - 如果從數據庫中獲得的響應是正確的，那麼我們不需要知道該代碼的作用。 –