Скачать или смотреть Download XML from a Web Server: Android Programming

Tutorial showing how to download XML data from a sample Google AppEngine web server (http://demoprojectserver1234.appspot....) in an Android project. Full Android code below.

// imports omitted due to YouTube space restriction!
// Some code based on content in Android Application Development in 24 hours by Darcey and Conder (2nd ed).
/**
Demonstrate querying a basic application server for information.
*
*/
public class MainActivity extends Activity {
private static final String TAG = "ProjectServerDemo";

public static final String APP_ID = "3fa19507-c746-4dfa-8ded-ec60ef4d30d9";
public static final String SERVER_URL = "http://demoprojectserver1234.appspot....";
public static final String QUERY_FILE = "xmlquery.cgi";
public static final String QUERY_OPTIONS = "?appid=" + APP_ID;
public static final String QUERY_URL = SERVER_URL + QUERY_FILE + QUERY_OPTIONS;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}

public void onClick_ClearDisplay(View v) {
TextView textView = (TextView) findViewById(R.id.displayData);
textView.setText("");
}

public void onClick_QueryServer(View v) {
Log.i(TAG, "Query server...");
AsyncDownloader downloader = new AsyncDownloader();
downloader.execute();
}

private void handleNewRecord(String itemId, String data) {
TextView textView = (TextView) findViewById(R.id.displayData);
String message =
textView.getText().toString() + "\n" +
itemId + ": " + data;

textView.setText(message);
}


// Inner class for doing background download.
// REVISIT:- Change the [[ to a less than; ]] to a greater than.
// (YouTube won't let you use those characters...)
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 {
Log.i(TAG, "Now downloading...");
URL xmlUrl = new URL(QUERY_URL);
XmlPullParser receivedData = XmlPullParserFactory.newInstance().newPullParser();
receivedData.setInput(xmlUrl.openStream(), null);
return receivedData;
} catch (XmlPullParserException e) {
Log.e(TAG, "XmlPullParserExecption", e);
} catch (IOException e) {
Log.e(TAG, "XmlPullParserExecption", e);
}
return null;
}

private int tryParsingXmlData(XmlPullParser receivedData) {
if (receivedData != null) {
try {
return processReceivedData(receivedData);
} catch (XmlPullParserException e) {
Log.e(TAG, "Pull Parser failure", e);
} catch (IOException e) {
Log.e(TAG, "IO Exception parsing XML", e);
}
}
return 0;
}

private int processReceivedData(XmlPullParser xmlData) throws XmlPullParserException, IOException {
int recordsFound = 0;

// Find values in the XML records
String appId = ""; // Attributes
String itemId = "";
String timeStamp = "";
String data = ""; // Text

int eventType = -1;
while (eventType != XmlResourceParser.END_DOCUMENT) {
String tagName = xmlData.getName();

switch (eventType) {
case XmlResourceParser.START_TAG:
// Start of a record, so pull values encoded as attributes.
if (tagName.equals("record")) {
appId = xmlData.getAttributeValue(null, "appid");
itemId = xmlData.getAttributeValue(null, "itemid");
timeStamp = xmlData.getAttributeValue(null, "timestamp");
data = "";
}
break;

// Grab data text (very simple processing)
// NOTE: This could be full XML data to process.
case XmlResourceParser.TEXT:
data += xmlData.getText();
break;

case XmlPullParser.END_TAG:
if (tagName.equals("record")) {
recordsFound++;
publishProgress(appId, itemId, data, timeStamp);
}
break;
}
eventType = xmlData.next();
}

// Handle no data available: Publish an empty event.
if (recordsFound == 0) {
publishProgress();
}
Log.i(TAG, "Finished processing "+recordsFound+" records.");
return recordsFound;
}

@Override
protected void onProgressUpdate(String... values) {
if (values.length == 0) {
Log.i(TAG, "No data downloaded");
}
if (values.length == 4) {
String appId = values[0];
String itemId = values[1];
String data = values[2];
String timeStamp = values[3];

// Log it
Log.i(TAG, "AppID: " + appId + ", Timestamp: " + timeStamp);
Log.i(TAG, " ItemID: " + itemId + ", Data: " + data);

// Pass it to the application
handleNewRecord(itemId, data);

}
super.onProgressUpdate(values);
}
}
}