我正在尝试通过 url 从 XML 文件中获取特定标签中包含的数据。特定标签称为start_address. 我不确定在这种情况下使用什么方法。这是我要连接到的确切 XML 文件的链接
http://maps.googleapis.com/maps/api/directions/xml?origin=07306&destination=07306&sensor=false
//主要活动
package com.example.xmlread;
import java.io.IOException;
import java.net.URL;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;
import android.support.v7.app.ActionBarActivity;
import android.content.res.XmlResourceParser;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends ActionBarActivity {
public static Button GetDir, Clear;
public static EditText StartDes, EndDes;
public static String TAG = "GoogleDirectionAPI";
//public static String STARTING_DESTINATION = StartDes.getText().toString();
//public static String ENDING_DESTINATION = EndDes.getText().toString();
//public static final String QUERY_URL = "http://maps.googleapis.com/maps/api/directions/xml?origin=" + STARTING_DESTINATION + "&destination=" + ENDING_DESTINATION + "&sensor=false";
public static final String TEST_URL = "http://maps.googleapis.com/maps/api/directions/xml?origin=07306&destination=07306&sensor=false";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void ClearDisplay(View v){
}
public void GetDirections(View v){
Log.i(TAG, "Query Server..");
AsyncDownloader downloader = new AsyncDownloader();
downloader.execute();
}
@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;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
//background downloading for XML data
private class AsyncDownloader extends AsyncTask<Object, String, Integer>{
@Override
protected Integer doInBackground(Object... arg0){
XmlPullParser receivedData = tryDownloadingXmlData();
int RecordsFound = tryParsingXmlData(receivedData);
return RecordsFound;
}
private XmlPullParser tryDownloadingXmlData() {
try{
URL xmlUrl = new URL(TEST_URL);
XmlPullParser recieveData = XmlPullParserFactory.newInstance().newPullParser();
recieveData.setInput(xmlUrl.openStream(), null);
return recieveData;
}catch (XmlPullParserException e){
Log.e(TAG,"XmlPullParserException", e);
}catch (IOException e){
Log.e(TAG, "XmlPullParserException", e);
}
return null;
}
@Override
protected void onProgressUpdate(String... values){
if(values.length == 0){
Log.i(TAG, "No data downloaded");
}
if(values.length == 1){
String start_address = values[0];
//String end_address = values[1];
//String html_instructions = values[2];
//log
Log.i(TAG, "Start Address: " + start_address);
//Log.i(TAG, "Ending Address: "+ end_address);
//Log.i(TAG, "html instructions: " + html_instructions);
}
super.onProgressUpdate(values);
}
private int tryParsingXmlData(XmlPullParser receivedData) {
if(receivedData != null){
return processRecievedData(receivedData);
}
return 0;
}
private int processRecievedData(XmlPullParser receivedData) {
// TODO Auto-generated method stub
int eventType = -1;
int recordsFound = 0;
//find values in XML records
String start_address = "";
//String end_address = "";
//String html_instructions = "";
while(eventType != XmlResourceParser.END_DOCUMENT){
String tagName = receivedData.getName();
//problem starts here!!
switch(eventType){
case XmlResourceParser.START_TAG:
if(tagName.equals("start_address")){
//pull value
start_address = receivedData.getText(); // get text contained inside the start_address tag (not working and returns null)
}
break;
case XmlPullParser.END_TAG:
if(tagName.equals("start_address")){
recordsFound++;
publishProgress(start_address);
}
break;
}
try {
eventType = receivedData.next();
} catch (XmlPullParserException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//if no data is found, publish empty event
if(recordsFound == 0){
publishProgress();
}
Log.i(TAG, "Processed: "+ recordsFound + " Records");
return recordsFound;
}
}
}