Access Web Services Using the GET Method
Description
To Access Web Services Using the GET Method involves the following steps:
- download XML files
- parse the contents
Example
The following code shows how to Access Web Services Using the GET Method.
Add the following statement to the AndroidManifest.xml file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.java2s.myapplication3.app" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="java2s.com"
android:theme="@style/AppTheme" >
<activity
android:name="com.java2s.myapplication3.app.MainActivity"
android:label="java2s.com"
>
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Layout xml file
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<ImageView
android:id="@+id/img"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center" />
</LinearLayout>
Main Activity Java code
package com.java2s.myapplication3.app;
/*w w w . j a v a 2s .co m*/
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ImageView;
import android.widget.Toast;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
public class MainActivity extends Activity {
ImageView img;
private InputStream OpenHttpConnection(String urlString) throws IOException {
InputStream in = null;
int response = -1;
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
if (!(conn instanceof HttpURLConnection))
throw new IOException("Not an HTTP connection");
try {
HttpURLConnection httpConn = (HttpURLConnection) conn;
httpConn.setAllowUserInteraction(false);
httpConn.setInstanceFollowRedirects(true);
httpConn.setRequestMethod("GET");
httpConn.connect();
response = httpConn.getResponseCode();
if (response == HttpURLConnection.HTTP_OK) {
in = httpConn.getInputStream();
}
} catch (Exception ex) {
throw new IOException("Error connecting");
}
return in;
}
private String WordDefinition(String word) {
InputStream in = null;
String strDefinition = "";
try {
in = OpenHttpConnection("http://your server.com/query?word=" + word);
Document doc = null;
DocumentBuilderFactory dbf =
DocumentBuilderFactory.newInstance();
DocumentBuilder db;
try {
db = dbf.newDocumentBuilder();
doc = db.parse(in);
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
doc.getDocumentElement().normalize();
//---retrieve all the <Definition> elements---
NodeList definitionElements =
doc.getElementsByTagName("Definition");
//---iterate through each <Definition> elements---
for (int i = 0; i < definitionElements.getLength(); i++) {
Node itemNode = definitionElements.item(i);
if (itemNode.getNodeType() == Node.ELEMENT_NODE) {
//---convert the Definition node into an Element---
Element definitionElement = (Element) itemNode;
}
}
} catch (IOException e1) {
Log.d("NetworkingActivity", e1.getLocalizedMessage());
}
//---return the definitions of the word---
return strDefinition;
}
private class AccessWebServiceTask extends AsyncTask<String, Void, String> {
protected String doInBackground(String... urls) {
return WordDefinition(urls[0]);
}
protected void onPostExecute(String result) {
Toast.makeText(getBaseContext(), result, Toast.LENGTH_LONG).show();
}
}
/**
* Called when the activity is first created.
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//---access a Web Service using GET---
new AccessWebServiceTask().execute("apple");
}
}