Can't make instance from java class

Question

I write code for MSN application , and this application connection with server ASP.NET this code run perfectly in my computer , but when I run this code in other computer it is giving me runtime error in this line

new SigninPerson(s1,s2);

Error:

could not find class 'com.example.hello.Signinperson' referenced from method
com.example.hello.MainActivity.GoToProfileActivity

Code:

public class MainActivity extends Activity {
    public final String URL="http://10.0.2.2:47102/ProjectTwo/Service.asmx";
    public final String NAMESPACE="http://tempuri.org/";
    public final String METHOD= "signin";
    public final String ACTION = "http://tempuri.org/signin";
    private EditText EditTextEmail;
    private EditText EditTextPass;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    public void GoToSignupActivity (View V)
    {
        Intent SignupAct = new Intent("com.example.hello.SignupActivity");
        startActivity(Intent.createChooser(SignupAct, "Choose an Application"));
    }
    public void GoToProfileActivity (View V)
    {
        EditTextEmail = (EditText) findViewById(R.id.Edit_Text_Email);
        EditTextPass = (EditText) findViewById(R.id.Edit_Text_Pass);
        if (isEmptyEditText(EditTextEmail) | isEmptyEditText(EditTextPass)) 
        {
            showDialog(0);
        }
        else
        {
            String s1 = EditTextEmail.getText().toString().trim();
            String s2 = EditTextPass.getText().toString().trim();
            SigninPerson SIPerson = new SigninPerson(s1,s2);
            SoapObject Req = new SoapObject(NAMESPACE, METHOD);
            PropertyInfo p = new PropertyInfo();
            p.setName("SIPerson");
            p.setValue(SIPerson);
            p.setType(SIPerson.getClass());
            Req.addProperty(p);
            SoapSerializationEnvelope env = new SoapSerializationEnvelope(SoapSerializationEnvelope.VER11);
            env.dotNet = true;

            env.setOutputSoapObject(Req);
            env.addMapping(NAMESPACE, "SigninPerson", new SigninPerson().getClass());
            HttpTransportSE ahttp = new HttpTransportSE(URL);
            SoapObject Res = null;
            try
            {
                ahttp.call(ACTION, env);
                Res = (SoapObject) env.getResponse();
            }
            catch (Exception ex)
            {
                ex.printStackTrace();
            }
            if (Integer.parseInt(Res.getProperty(0).toString())==0)
            {
                showDialog(1);
            }
            else
            {
                SIPerson.Person_Id = Integer.parseInt(Res.getProperty(0).toString());
                SIPerson.F_Name = Res.getPropertyAsString(1).toString();
                SIPerson.L_Name = Res.getPropertyAsString(2).toString();
                SIPerson.E_Mail = Res.getPropertyAsString(3).toString();
                SIPerson.Password = Res.getPropertyAsString(4).toString();
                Intent ProfileAct = new Intent("com.example.hello.ProfileActivity");
                ProfileAct.putExtra("ReciveLogin", SIPerson);
                startActivity(Intent.createChooser(ProfileAct, "Choose an Application"));
            }
        }
    }
    public boolean isEmptyEditText (EditText ET)
    {
        boolean isEmpty = true;
        if (ET.getText().toString().trim().length() > 0)
        {
            isEmpty = false;
        }
        return isEmpty;
    }
    @Override
    protected Dialog onCreateDialog(int id)
    {
        switch (id)
        {
        case 0:
            Dialog EnterBothDialog = new Dialog(this);
            EnterBothDialog.setTitle("Please Enter Both E-Mail / Password");
            return EnterBothDialog;
        case 1:
            Dialog InvalidEmPass = new Dialog(this);
            InvalidEmPass.setTitle("Invalid Email / Password");
            return InvalidEmPass;
        }
        return null;
    }
}

and this is SigninPerson

public class SigninPerson implements KvmSerializable, Serializable {
    public int Person_Id;
    public String F_Name;
    public String L_Name;
    public String E_Mail;
    public String Password;
    public SigninPerson () 
    {
    }
    public SigninPerson (int id, String Fname, String Lname, String Email, String Pass)
    {
        Person_Id = id;
        F_Name = Fname;
        L_Name = Lname;
        E_Mail = Email;
        Password = Pass;
    }

    public SigninPerson (String Email, String Pass)
    {
        Person_Id = 0;
        F_Name = "";
        L_Name = "";
    }
    @Override
    public Object getProperty(int arg0) {
        // TODO Auto-generated method stub
        switch (arg0)
        {
        case 0:
            return Person_Id;
        case 1:
            return F_Name;
        case 2:
            return L_Name;
        case 3:
            return E_Mail;
        case 4:
            return Password;
        }
        return null;
    }

    @Override
    public int getPropertyCount() {
        // TODO Auto-generated method stub
        return 5;
    }

    @Override
    public void getPropertyInfo(int arg0, Hashtable arg1, PropertyInfo arg2) {
        // TODO Auto-generated method stub
        switch (arg0)
        {
        case 0:
            arg2.type = PropertyInfo.INTEGER_CLASS;
            arg2.name = "Person_Id";
            break;
        case 1:
            arg2.type = PropertyInfo.STRING_CLASS;
            arg2.name = "F_Name";
            break;
        case 2:
            arg2.type = PropertyInfo.STRING_CLASS;
            arg2.name = "L_Name";
            break;
        case 3:
            arg2.type = PropertyInfo.STRING_CLASS;
            arg2.name = "E_Mail";
            break;
        case 4:
            arg2.type = PropertyInfo.STRING_CLASS;
            arg2.name = "Password";
            break;
            default:break;
        }
    }

    @Override
    public void setProperty(int arg0, Object arg1) {
        // TODO Auto-generated method stub
        switch (arg0)
        {
        case 0:
            Person_Id = Integer.parseInt(arg1.toString());
            break;
        case 1:
            F_Name = arg1.toString();
            break;
        case 2:
            L_Name = arg1.toString();
            break;
        case 3:
            E_Mail = arg1.toString();
            break;
        case 4:
            Password = arg1.toString();
            break;
            default:break;
        }
    }

}

but when I delete implements from SigninPerson and Override

public class SigninPerson{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    public int Person_Id;
    public String F_Name;
    public String L_Name;
    public String E_Mail;
    public String Password;
    public SigninPerson () 
    {
    }
    public SigninPerson (int id, String Fname, String Lname, String Email, String Pass)
    {
        Person_Id = id;
        F_Name = Fname;
        L_Name = Lname;
        E_Mail = Email;
        Password = Pass;
    }

    public SigninPerson (String Email, String Pass)
    {
        Person_Id = 0;
        F_Name = "";
        L_Name = "";
    }
}

it is make new for SigninPerson and don't give me run time

I am trying to found the problem long time but I can't find any wrong

please , anyone can help me

because I must send my application in the morning

Answer 1

You should change this line:

SigninPerson SIPerson = null;
new SigninPerson(s1,s2);

to:

SigninPerson SIPerson = new SigninPerson(s1,s2);

Answer 2

It'll give you a NullPointerException as you declared a reference for the SigninPerson , but you never assigned it to a new object of this class as @SOfanatic recommended for you ( +1 for him).

 SigninPerson SIPerson = null;// << here assign SIPerson to new SigninPerson
    //....
     p.setValue(SIPerson);
     p.setType(SIPerson.getClass());