Get event click list item in J2ME - java-me

Question

I want to create small app. I will login with user and password, then display option to select. If select option, display alert corresspondingly. But I can't get event click item in list.
Here is code:
public class Midlet extends MIDlet implements CommandListener{
private Display display;
private SampleCavans myCanvas;
private TextField username;
private TextField password;
private Form form;
private Command cancel;
private Command login;
private Command mNextCommand;
private List service;
String[] stringElements = { "Check Mail", "Compose","Addresses","Options","Signout","Calculator"};
public Midlet() {
display=Display.getDisplay(this);
username=new TextField("Login ID", "", 10, TextField.ANY);
password=new TextField("Password", "", 10, TextField.PASSWORD);
cancel=new Command("Cancel", Command.CANCEL, 2);
login=new Command("Login", Command.OK, 2);
form=new Form("Sign in");
form.append(username);
form.append(password);
form.addCommand(cancel);
form.addCommand(login);
form.setCommandListener(this);//add event click for form
myCanvas=new SampleCavans();
}
public void startApp() {
display.setCurrent(form);
}
public void pauseApp() {
}
public void destroyApp(boolean unconditional) {
notifyDestroyed();
}
public void menu()
{
//List service=new List("Choice one",Choice.EXCLUSIVE);
service=new List("Choice one",Choice.EXCLUSIVE,stringElements,null);
service.setCommandListener(this);
//service.addCommand(mNextCommand);
display.setCurrent(service);
}
public void tryAgain()
{
Alert error=new Alert("Login Incorrect","Please try again",null,AlertType.ERROR);
error.setTimeout(Alert.FOREVER);
username.setString("");
password.setString("");
display.setCurrent(error,form);
}
public void commandAction(Command c, Displayable d) {
String lable=c.getLabel();
if(lable.equals("Cancel"))
{
destroyApp(true);
}
else if(lable.equals("Login"))
{
validateUser(username.getString(),password.getString());
}
else if(c==List.SELECT_COMMAND)
{
int index = service.getSelectedIndex();
Alert alert = new Alert("Your selection",
"You chose " + service.getString(index) + ".",
null, AlertType.INFO);
Display.getDisplay(this).setCurrent(alert, service);
}
}
private void validateUser(String name, String pass) {
if(name.equals("12")&&pass.endsWith("12"))
{
menu();
}
else
tryAgain();
}

Answer 1

In midp a list is actually more like a menu with a selection of choices. You have to set a command on it, so that in your command action you can dispatch on this command, get the selection form the menu and set the next screen accordingly. Here's the code for something similar to what you are trying to do:
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.List;
import javax.microedition.lcdui.TextBox;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
public class Login extends MIDlet implements CommandListener {
private static final String ONE = "One";
private static final String THE_OTHER = "The Other";
private Form form;
private Command cancel=new Command("Cancel", Command.CANCEL, 2);
private Command login=new Command("Login", Command.OK, 2);
private TextField username=new TextField("Login ID", "", 10, TextField.ANY);
private TextField password=new TextField("Password", "", 10, TextField.PASSWORD);
private List menu = new List("Menu", List.IMPLICIT, new String[] {"One", "The Other"}, null);
private Command selection=new Command("SELECTION", Command.ITEM, 1);
private TextBox message1= new TextBox("One", ONE, ONE.length(), TextField.UNEDITABLE);
private TextBox message2= new TextBox("The Other", THE_OTHER, THE_OTHER.length(), TextField.UNEDITABLE);
public Login() {
form=new Form("Sign in");
form.append(username);
form.append(password);
form.addCommand(cancel);
form.addCommand(login);
form.setCommandListener(this);
menu.setSelectCommand(selection);
menu.setCommandListener(this);
message1.addCommand(cancel);
message1.setCommandListener(this);
message2.addCommand(cancel);
message2.setCommandListener(this);
}
protected void destroyApp(boolean unconditional)
throws MIDletStateChangeException {
username.delete(0, username.size());
password.delete(0, password.size());
}
protected void pauseApp() { }
protected void startApp() throws MIDletStateChangeException {
Display.getDisplay(this).setCurrent(form);
}
public void commandAction(Command c, Displayable d) {
if(c == cancel) {
if(d == form) {
notifyDestroyed();
}
else {
Display.getDisplay(this).setCurrent(form);
}
}
if(c == login) {
char[] data1 = new char[10];
username.getChars(data1);
char[] data2 = new char[10];
password.getChars(data2);
if(loginOk(new String(data1), new String(data2))) {
Display.getDisplay(this).setCurrent(menu);
}
else {
notifyDestroyed();
}
}
if(c == selection) {
if(menu.getSelectedIndex() == 0) {
Display.getDisplay(this).setCurrent(message1);
}
if(menu.getSelectedIndex() == 1) {
Display.getDisplay(this).setCurrent(message2);
}
}
}
private boolean loginOk(String string, String string2) {
return true;
}
}