Simple Java Calculator

package pongdroid.com;

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

public class PongDroidActivity extends Activity implements OnClickListener {
    private Button sumar,restar,multiplicar,dividir;
    private TextView resultado;
    private MultiAutoCompleteTextView numberone,numbertwo;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            sumar = (Button) findViewById(R.id.buttonSumar);
            restar = (Button) findViewById(R.id.buttonRestar);
            multiplicar = (Button) findViewById(R.id.buttonMultiplicar);
            dividir = (Button) findViewById(R.id.buttonDividir);
            resultado = (TextView) findViewById(R.id.resultado);
            numberone = (MultiAutoCompleteTextView) findViewById(R.id.numberone);
            numbertwo = (MultiAutoCompleteTextView) findViewById(R.id.numbertwo);
            sumar.setOnClickListener(this);
            restar.setOnClickListener(this);
            multiplicar.setOnClickListener(this);
            dividir.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        Button view = (Button) v;
        double result = 0,num1 = 0,num2 = 0;
        num1 = Double.valueOf(numberone.getText().toString());
        num2 = Double.valueOf(numbertwo.getText().toString());
         switch(view.getId()){
          case R.id.buttonSumar:
                result = num1+num2;
                break;
          case R.id.buttonRestar:
                result = num1-num2;
                break;
          case R.id.buttonMultiplicar:
                result = num1*num2;
                break;
          case R.id.buttonDividir:
                result = num1/num2;
                break;
          }
         resultado.setText(String.valueOf(result));
    }


}