J2ME ask

what must i'm add so this coding display addition, my problem is, when i click a result button at emulator j2me, the addition function not responding , can somebody tell me what i supposed to do? thanks before

Code:

package org.itmaranatha.MobileTest1;

import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;

/**
 * @author Erdy rezki
 */
public class MidletPraktikum extends MIDlet {

    private Command cmdAdd, cmdResult, cmdExit, cmdClear;
    private int bil1, bil2, hasil = 0;
    private TextBox txtBox;

    public MidletPraktikum() {
        txtBox = new TextBox("", "", 100, 5);
        cmdAdd = new Command("Add", Command.SCREEN, 0);
        cmdResult = new Command("Result", Command.SCREEN, 0);
        cmdExit = new Command("Exit", Command.EXIT, 0);
        cmdClear = new Command("Clear", Command.SCREEN, 0);

        txtBox.addCommand(cmdAdd);
        txtBox.addCommand(cmdExit);

        txtBox.setCommandListener(new CommandListener() {

            public void commandAction(Command c, Displayable d) {
                if (c.equals(cmdAdd)) {
                    bil1 = Integer.parseInt(txtBox.getString());
                    txtBox.setString("");
                    txtBox.removeCommand(cmdAdd);
                    txtBox.addCommand(cmdResult);
                    
                } else if (c.equals(cmdResult)) {
                    bil2 = Integer.parseInt(txtBox.getString());
                    hasil = bil1 + bil2;
                    txtBox.setString(" Result from " + bil1 + "+" + bil2 + "is" + hasil);
                    txtBox.removeCommand(cmdClear);

                } else if (c.equals(cmdClear)) {
                    txtBox.setString("");
                    txtBox.removeCommand(cmdClear);
                    txtBox.setConstraints(5);
                    txtBox.removeCommand(cmdResult);

                } else if (c.equals(cmdExit)) {
                    destroyApp(true);
                    notifyDestroyed();
                    notifyDestroyed();

                }
            }
        });
    }

    public void startApp() {
        Display.getDisplay(MidletPraktikum.this).setCurrent(txtBox);
    }

    public void pauseApp() {
    }

    public void destroyApp(boolean unconditional) {
    }
}

 

You don't have

Code:

txtBox.addCommand(cmdResult);
txtBox.addCommand(cmdClear);

so I doubt those commands are active.