Rather than printing the result from the webservice, my activity just writes "TextView"

Question

I want my practice app to use the soap web service from w3schools and converts a celcius temperature to fahrenheit, and display the converted temperature in a textview. But it is rather just writing "TextView" on the screen. The LogCat just says,

"Emulator without GPU detected."

What should I do?

 package com.falafel.MyTest;
//ANDROID CLIENT OF SOAP WEB SERVICES. SAMPLE (YOUTUBE) CLIENT.
import org.ksoap2.SoapEnvelope;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapPrimitive;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.TextView;


public class FirstScreen extends Activity {

    private static final String SOAP_ACTION= "http://www.w3schools.com/webservices/CelsiusToFahrenheit"; //soapAction will point to where the namespace is, slash, the name of the method
    private static final String NAMESPACE = "http://www.w3schools.com/webservices/";
    private static final String METHOD_NAME= "CelsiusToFahrenheit";
    private static final String URL= "http://www.w3schools.com/webservices/tempconvert.asmx";//This URL is very important. Make sure it is pointing to asmx, and not to wsdl, that is a complete URL to where the web service itself is; This is not a WSDL file.

    TextView tv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        tv = (TextView) findViewById(R.id.textView1);
        String[] params= {SOAP_ACTION, NAMESPACE, METHOD_NAME, URL};
        new MyTask().execute(params);
    }

        private class MyTask extends AsyncTask<String, Void, SoapPrimitive>{

            @Override
            protected SoapPrimitive doInBackground(String... params) {
                //Soap Portion of this client program starts here. This is 1/3rd of the major functionality of this program, since there are three major portions.
                SoapObject Request = new SoapObject(params[1], params[2]);//If we CelsiusToFahrenheit dint take any parameters, I would be done with my soap request by this line. But it does take a string parameter (as we say in the wsdl), so we need to package the required parameters into the Request. That is, next line!
                Request.addAttribute("Celsius", "32"); //Celcius is the name of the parameter required by the function. 32 --> we are giving a hardcoded value here for simplicity. | We have to add this line for each required parameter.


                //Here starts the 2nd out of 3 major portions of this program. This portion is the SoapSerializationEnvelope, which is an important piece of what needs to happen in ksoap to call web services inside of android.
                SoapSerializationEnvelope soapEnvelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); //An important thing in creating this object is specifying which version of the soap specification we want to use. This is version 1.1
                                                                                                    //soapEnvelope is an in and out object, which means that it has 2 types of information clusters, named bodyIn which contains information we send to web service while making the call (i.e. the xml going out), and named bodyOut which brings back, from the web service, the response of the call to the web service (that is the xml coming in).
                soapEnvelope.dotNet= true; //Remember the asmx in the URL, that is this service is based in ASP.Net, and not PHP or something, so you have to specify that. If you forget to specify that, you'll get some errors complaining that some of your objects are NULL. And the tricky part is that sometimes it will work, so yeah! If you are sure that yours is a dotNet based web service, always be safe by setting it to true, and if it is not dotNet based, you'll have to set it to nottrue
                soapEnvelope.setOutputSoapObject(Request); //Pass the packaged Request to SoapEnvelope itself. SetOutputSoapObject() assigns the object to the envelope as the outbound message for the soap call.


                //3rd of the 3 major parts of this program:- Transport (HTTP transport itself)
                HttpTransportSE hts= new HttpTransportSE(params[3]);
                SoapPrimitive resultString=new SoapPrimitive("sorry","sorry","sorry");
                try{   //try-catch block to actually make the call
                    hts.call(params[0], soapEnvelope); //SOAP_ACTION contains where the web service is, appended with the function to be invoked. While all the information which needs to be sent to the web service is present (like Request) in the bodyIn portion of the soapEnvelope. After the call is successful (i.e. after the execution of this line, the bodyOut portion of this envelope will contain the response of the webservice.
                    resultString = (SoapPrimitive) soapEnvelope.getResponse();
                    //tv.setText("Status : " + resultString);
                }   
                catch (Exception e){
                    e.printStackTrace();
                }
                return resultString;
            }

            @Override 
            protected void onPostExecute(SoapPrimitive resultString){
                tv.setText("Status: " + resultString.toString());
            }
    }
}

EDIT:-

I edited the above code after implementing the first two answers. But the result was "Status:False" for the first time and then it is again "TextView" on the screen.

Plus what is even more confusing is that following is the entire content of the LogCat, although I tested it on two different emulators:

04-04 04:08:56.355: D/gralloc_goldfish(1115): Emulator without GPU emulation detected.
04-04 04:08:57.705: D/dalvikvm(1115): GC_FOR_ALLOC freed 86K, 5% free 3088K/3244K, paused 65ms, total 73ms
04-04 04:08:59.905: D/dalvikvm(1115): GC_FOR_ALLOC freed 405K, 14% free 3185K/3664K, paused 52ms, total 52ms

EDIT:-

It is again printing "Status:False". This is I think the exception caught. But why this unpredictable behavior?

Answer 1

You have declared the MyTask but are you executing it? I think you are missing something like

new MyTask().execute(params); 

in your onCreate.

As for the "Emulator without GPU detected.", this isn't in any way connected to the issue you are facing.

Other than that, your code contains some other problems. For example, in your onPostExecute, you might need to call .toString() to resultString.

Answer 2

If you are doing what fremmedehenvendelser has pointed out,then either of the following might be the case :

1.Should'nt the resultString be typecasted into a string before it is assigned to the textview 2.If resultString is getting the right value,probably your textview is then not on the UI thread,you should either try using runonUithread or pass the textView's reference to this asyncTask and then update the reference.