Part 2 : Calling a webservice from Android Application

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Part 2: Calling webservice from Android App

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Refer part 1: For Creating a WSDL service

• Create a new android project in eclipse.

• Select Finish.
• We need to display 4 calculations in android application. UI is on fron end, but calculation is done in backend with the help of Web service. (Explained in part 1).
• So we will create 4 text Inputs in main.xml

• Finally main.xml should contain four text fields for four different calculations
• <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:id="@+id/txtAddition" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="@string/hello" />
<TextView android:id="@+id/txtSubraction" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="@string/hello" />
<TextView android:id="@+id/txtMultiplication" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="@string/hello" />
<TextView android:id="@+id/txtDivision" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="@string/hello" />
</LinearLayout>
• We need Ksoap Library File for android project, which can downloaded from this link.
• Since we are trying to access the data stored on server which is equivalent to android app accessing an internet, so we have to allow our android application to access the internet.
• we have to include “<uses-permission android:name=”android.permission.INTERNET” />” inside AndroidManifest.xml.
• We have to include the above tag inside the tag manifest but outside the tag application.
• Next point includes the complete Code for adding two numbers. With minute changes we can also work with multiplication, subraction and division.
• ————————————————————————————————–
• package org.web.frontend.calculator;
import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;public class AndroidWSDLFrontEnd extends Activity {

  private String METHOD_NAME = “sum”; // our webservice method name
  private String NAMESPACE = “http://calculator.backend.web.org&#8221;; // Here package name in webservice with reverse order.
  private String SOAP_ACTION = NAMESPACE + METHOD_NAME; // NAMESPACE + method name
  private static final String URL = “http://192.168.0.103:8080/AndroidBackend/services/Calculate?wsdl&#8221;; // you must use ipaddress here, don’t use Hostname or localhost

  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  TextView tv = (TextView) findViewById(R.id.txtAddition);
  try
  {
  SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
  request.addProperty(“i”, 5);
  request.addProperty(“j”, 15);
  SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
  envelope.dotNet = true;
  envelope.setOutputSoapObject(request);
  HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);
  androidHttpTransport.call(SOAP_ACTION,envelope);
  Object result = envelope.getResponse();
  System.out.println(“Result : ” + result.toString());
  ((TextView) findViewById (R.id.txtAddition)).setText(“Addition : “+result.toString());
  } catch (Exception E) {
  E.printStackTrace();
  ((TextView) findViewById (R.id.txtAddition)).setText(“ERROR:”    + E.getClass().getName() + “:” + E.getMessage());
  }
  }
  }

• ————————————————————————————————–
• Imp Points to note down before You go through this code

1. NAMESPACE = “http://calculator.backend.web.org&#8221;; We refer this name from the actual web project on backend. The name of package on backend on serverside was org.web.backend.calculator. So we need to write the reverse order of package name.
2. URL = “http://192.168.0.103:8080/AndroidBackend/services/Calculate?wsdl&#8221;; Here Your comp Ip addr is required. Localhost wont work.
3. Thats it, you can run the following application. Before running the app, make sure your server is running on Backend. And you will get the following screen on Emulator.

• For multiplication, Change  METHOD_NAME = “multiply”; Simillarly “divide or subtract ” for desired operations.
• We get 3 printout statements of “Hello World , AndroidWSDLFrontEnd” because 1 text input holds for addition, 2 text input for Subtraction, 3 text input for Multiplication, 4 text input for Division as discussed in main.xml
• So for METHOD_NAME = “sum”; we have allocated (R.id.txtAddition);
• Simillarly we can go for different desired operations.

• Thats it. We have sucessfully called the wsdl file on server Side.
• If You have any problems with the above blog, plz feel free to contact me at depo.jatin@gmail.com

• Reference

1. http://lukencode.com/2010/04/27/calling-web-services-in-android-using-httpclient/
2. http://www.eclipse.org/webtools/community/tutorials/BottomUpAxis2WebService/bu_tutorial.html
3. http://androidcommunity.com/forums/340658-post6.html

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Jatinkumar DN Patel – Thinking High To RISE.

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package org.web.frontend.calculator;import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class AndroidWSDLFrontEnd extends Activity {

private String METHOD_NAME = “sum”; // our webservice method name
private String NAMESPACE = “http://calculator.backend.web.org&#8221;; // Here package name in webservice with reverse order.
private String SOAP_ACTION = NAMESPACE + METHOD_NAME; // NAMESPACE + method name
private static final String URL = “http://192.168.0.103:8080/AndroidBackend/services/Calculate?wsdl&#8221;; // you must use ipaddress here, don’t use Hostname or localhost

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

TextView tv = (TextView) findViewById(R.id.txtAddition);
try
{
SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
request.addProperty(“i”, 5);
request.addProperty(“j”, 15);
SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
envelope.dotNet = true;
envelope.setOutputSoapObject(request);
HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);
androidHttpTransport.call(SOAP_ACTION,envelope);
Object result = envelope.getResponse();
System.out.println(“Result : ” + result.toString());
((TextView) findViewById (R.id.txtAddition)).setText(“Addition : “+result.toString());
} catch (Exception E) {
E.printStackTrace();
((TextView) findViewById (R.id.txtAddition)).setText(“ERROR:”    + E.getClass().getName() + “:” + E.getMessage());
}
}
}