J2ME GUI Controls - EventHandling

J2ME program for EventHandling

import javax.microedition.lcdui.*;

import javax.microedition.midlet.*;

public class EventHandlingMIDlet extends MIDlet implements CommandListener {

  private Display display;

  private List list;

  private TextBox input;

  private Command back, main, exit;

  private String currentItem;

    public EventHandlingMIDlet() {

    back = new Command("Back", Command.BACK, 0);

    main = new Command("Main", Command.SCREEN, 1);

    exit = new Command("Exit", Command.STOP, 2);

  }

    public void startApp() throws MIDletStateChangeException {

    display = Display.getDisplay(this);

    list = new List("Menu Items", Choice.IMPLICIT);

    list.append("EventItem1", null);

    list.append("EventItem2", null);

    list.append("EventItem3", null);

    list.append("EventItem4", null);

    list.addCommand(exit);

    list.setCommandListener(this);

    mainItem();

  }

  public void pauseApp() {

    display = null;

    list = null;

    input = null;

  }

  public void destroyApp(boolean unconditional) {

    notifyDestroyed();

  }

  void mainItem() {

    display.setCurrent(list);

    currentItem = "Main";

  }

  public void show() {

    input = new TextBox("Enter Text Here: ", "", 10, TextField.ANY);

    input.addCommand(back);

    input.setCommandListener(this);

    input.setString("");

    display.setCurrent(input);

  }

  public void commandAction(Command c, Displayable d) {

    String label = c.getLabel();

    if (label.equals("Exit")) {

      destroyApp(true);

    } else if (label.equals("Back")) {

      if(currentItem.equals("Eventitem1") || currentItem.equals("Eventitem2") ||

       currentItem.equals("Eventitem3") || currentItem.equals("Eventitem4")){

        mainItem();

      }

    } else {

      List down = (List)display.getCurrent();

      switch(down.getSelectedIndex()) {

        case 0: showItem();break;

        case 1: showItem2();break;

        case 2: showItem3();break;

        case 3: showItem4();break;

      }

    }

  }

  public void showItem() {

    show();

    currentItem = "Eventitem1";

  }

  public void showItem2() {

    show();

    currentItem = "Eventitem2";

  }

  public void showItem3() {

    show();

    currentItem = "Eventitem3";

  }

  public void showItem4() {

    show();

    currentItem = "Eventitem4";

  }

}

Output:-