Android development Web Service communication

   Compared with HTTP communication, HTTP cannot implement remote method invocation, but Web Service can. Web Service also has a server side and a client side. Generally, XFire is used to build the server. The client Android system does not provide an operation class library that directly calls each other with the Web Service. Generally, the class library provided by a third party can be used to complete the operation, and the Ksoap2 class library is more commonly used.
   A complete Web Service communication should have two parts: the construction of the server and the construction of the client. The construction of the server is cumbersome and can be realized with the help of MyEclipse8.5 with built-in Tomcat.
   In fact, there are many established servers on the Internet, which provide developed methods on the server side for external use. For example, many methods are disclosed on the http://www.webxml.com.cn server, such as weather conditions, Flight information, mobile phone attribution, etc., the client only needs to call these methods and related parameters, and can call these methods programmatically, without the need to create a server by itself.
   An example is written below:
   New main layout file:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <EditText
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/et"
        android:hint="Please enter a city"
        android:selectAllOnFocus="true"/>

    <Button
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/search_but"
        android:text="Get weather information"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/text"
        android:textSize="24sp"/>

</LinearLayout>

   Here is the main program class:

package xiao.fuyan.testapp;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;

/**
 * Created by xiao on 2017/2/3.
 */
public class WebServiceActivity extends Activity {
    private Button search_but;
    private TextView textView;
    private EditText et;

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

        et = (EditText) findViewById(R.id.et);
        search_but = (Button) findViewById(R.id.search_but);
        search_but.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String city = et.getText().toString();
                getWeather(city, " ");
            }
        });
    }

    //define the namespace
    private static final String NAMESPACE = "http://WebXml.com.cn/";
    //Define the URL that requests the WSDL document
    private static final String URL = "http://www.webxml.com.cn/WebServices/WeatherWS.asmx";
    //define the calling method
    private static final String METHOD_NAME = "getWeather";
    //Define namespace + call method name
    private static final String SOAP_ACTION = "http://WebXml.com.cn/getWeather";

    private SoapObject detail;

    public void getWeather(String city, String id){
        try {
            textView = (TextView) findViewById(R.id.text);
            //Instantiate the SoapObject object
            SoapObject rpc = new SoapObject(NAMESPACE, METHOD_NAME);
            //add parameters
            rpc.addProperty("thecityname", city);
            rpc.addProperty("id", id);

            //Instantiate the SoapSerializationEnvelope object
            SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
            //Encapsulate the input SoapObject object rpc
            envelope.bodyOut = rpc;
            //The server to be accessed is the .net server, otherwise set to false
            envelope.dotNet = true;
            //Set the SoapObject object to output
            envelope.setOutputSoapObject(rpc);
            //Specify the WSDL address
            HttpTransportSE ht = new HttpTransportSE(URL);
            // use debug
            ht.debug = true;

            //call web service
            ht.call(SOAP_ACTION, envelope);
            //Get the return information
            detail = (SoapObject) envelope.getResponse();
            textView.setText(detail.toString());
            return;
        }catch (Exception e){
            e.printStackTrace ();
        }
    }
}