Item Listener in J2ME

dalam programming pasti dikenal istilah even handler atau listener kalau di JAVA, even adalah kapan program disuru melakukan sesuatu atas perintah user,misalnya
onClick,button click,onChange n byk banget yang lainya yg tidak bisa aq sebutin 1 per 1 hehehe

nah kalo di desktop atau web application pastinya aq da terbiasa banget menggunakanx waktu develope suatu aplikasi
nah pertanyaanx gmn klo even atau listener pada mobile app dengan J2ME???
aq mulai cari2 ttg ini krn brhubungan dengan TA ku yaitu Mobile Commerce with J2ME
stlh googling akirx ketemu dah carax

simple n mudah ternyata
klo uda biasa coding pake Java pastix da tw donk Interface
nah tryt di J2ME da Interface yg namax ItemStateListener

1. langkah2 menggunakan ItemStateListener sebelumx qt mesti implement interface tersebut ke class Midlet qt seperti dibawah ini

public final class ContohListener extends MIDlet implements ItemStateListener

2. nah setelah qt lakukan diatas set ItemStateListener pada display

setItemStateListener (this);

3. default method harus ada dan method yg digunakan adalah
public void itemStateChanged(Item item) throws

UnsupportedFieldException {
if(item==e_gender) {
int index = e_gender.getSelectedIndex ();
System.out.println(“Error” + index);
switch (index) {
case 0:
System.out.println(“Male”);
break;
case 1:
System.out.println(“Female”);
break;
}
}
}

dan dibawah ini contoh code yang barusan aq bwt

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package main.app;
import java.io.*;
import java.util.*;
import javax.microedition.io.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.pim.UnsupportedFieldException;

/**
*
* @author harun
*/
public class FrmRegistration extends Form implements CommandListener,ItemStateListener {
private Display tampilanSebelumnya;
private Displayable dpySebelumnya;
private TextField txtSponsorName,txtName,txtAlamat,txtSponsor,txtTlp;
private Command cmdTambah,cmdKembali;
private DateField dob;

private String user;
private String password;
private String caption;
private String act;
private String[] stringArray = { “M”, “F” };
private ChoiceGroup e_gender;
private Image im,im2;
private StringItem space;

public FrmRegistration(Display dpy, Displayable prev){
super(“Form Registrasi”);

tampilanSebelumnya = dpy;
dpySebelumnya = prev;
txtName = new TextField(“Nama:”,”",50,TextField.ANY);
txtSponsor = new TextField(“ID Sponsor: “,”",8,TextField.NUMERIC);
txtSponsorName = new TextField(“Nama Sponsor:”,”",50,TextField.ANY);
txtAlamat = new TextField(“Alamat:”,”",50,TextField.ANY);
txtTlp = new TextField(“Telepon: “,”",15,TextField.NUMERIC);
caption = “Tambah”;
e_gender = new ChoiceGroup(“Search By: “, ChoiceGroup.POPUP, stringArray,null);
append(txtName);
append(txtSponsor);
append(txtSponsorName);
append(e_gender);
append(txtAlamat);
append(txtTlp);

cmdTambah = new Command(caption,Command.OK,1);
cmdKembali = new Command(“Kembali”,Command.BACK,1);
addCommand(cmdTambah);
addCommand(cmdKembali);
setCommandListener(this);
setItemStateListener (this);
space = new StringItem(“”,”");
append(space);
space.setLayout(Item.LAYOUT_CENTER);
}

public void commandAction(Command c,Displayable d){
if(c==cmdKembali){
tampilanSebelumnya.setCurrent(dpySebelumnya);
}else if(c==cmdTambah){

}
}

public void itemStateChanged(Item item) throws UnsupportedFieldException {
if(item==e_gender) {
int index = e_gender.getSelectedIndex ();
switch (index) {
case 0: txtSponsorName.setString(“Male”);
break;
case 1: txtSponsorName.setString(“Female”);
break;
}
}
}
}

oke slamat mencoba
ada pertanyaan silakan comment….
gud Luck