creating login screens in java

hello.

this is james mcfadden. i am trying to create a login screen in java. the problem i have is this: i am completely new to GUI programming. i know that i have to use strings. the code shown below is incomplete and when i try to compile it i get the following errors. how do i go about fixing these errors?

-jGRASP exec: javac -g X:\CP4B Project\LogOn.java

LogOn.java:11: ']' expected

username[0]="Administrator";

^

LogOn.java:11: <identifier> expected

username[0]="Administrator";

^

LogOn.java:12: ']' expected

username[1]="Ann Smyth";

^

LogOn.java:12: <identifier> expected

username[1]="Ann Smyth";

^

LogOn.java:13: ']' expected

username[2]="John Murphy";

^

LogOn.java:13: <identifier> expected

username[2]="John Murphy";

^

LogOn.java:14: ']' expected

username[3]="James McFadden";

^

LogOn.java:14: <identifier> expected

username[3]="James McFadden";

^

LogOn.java:15: ']' expected

username[4]="Frankie Ferry";

^

LogOn.java:15: <identifier> expected

username[4]="Frankie Ferry";

^

LogOn.java:16: ']' expected

username[5]="Daniel McKimm";

^

LogOn.java:16: <identifier> expected

username[5]="Daniel McKimm";

^

LogOn.java:17: ']' expected

username[6]="Stephen Doohan";

^

LogOn.java:17: <identifier> expected

username[6]="Stephen Doohan";

^

LogOn.java:18: ']' expected

username[7]="James Ferry";

^

LogOn.java:18: <identifier> expected

username[7]="James Ferry";

^

LogOn.java:19: ']' expected

username[8]="Liam Cannon";

^

LogOn.java:19: <identifier> expected

username[8]="Liam Cannon";

^

LogOn.java:20: ']' expected

username[9]="Ciaran Ferry";

^

LogOn.java:20: <identifier> expected

username[9]="Ciaran Ferry";

^

LogOn.java:21: ']' expected

username[10]="Ciaran McGee";

^

LogOn.java:21: <identifier> expected

username[10]="Ciaran McGee";

^

LogOn.java:23: ']' expected

password[0]="0";

^

LogOn.java:23: <identifier> expected

password[0]="0";

^

LogOn.java:24: ']' expected

password[1]="1";

^

LogOn.java:24: <identifier> expected

password[1]="1";

^

LogOn.java:25: ']' expected

password[2]="2";

^

LogOn.java:25: <identifier> expected

password[2]="2";

^

LogOn.java:26: ']' expected

password[3]="3";

^

LogOn.java:26: <identifier> expected

password[3]="3";

^

LogOn.java:27: ']' expected

password[4]="4";

^

LogOn.java:27: <identifier> expected

password[4]="4";

^

LogOn.java:28: ']' expected

password[5]="5";

^

LogOn.java:28: <identifier> expected

password[5]="5";

^

LogOn.java:29: ']' expected

password[6]="6";

^

LogOn.java:29: <identifier> expected

password[6]="6";

^

LogOn.java:30: ']' expected

password[7]="7";

^

LogOn.java:30: <identifier> expected

password[7]="7";

^

LogOn.java:31: ']' expected

password[8]="8";

^

LogOn.java:31: <identifier> expected

password[8]="8";

^

LogOn.java:32: ']' expected

password[9]="9";

^

LogOn.java:32: <identifier> expected

password[9]="9";

^

LogOn.java:33: ']' expected

password[10]="10";

^

LogOn.java:33: <identifier> expected

password[10]="10";

^

LogOn.java:57: <identifier> expected

button1.addActionListener(new ActionListener(){

^

LogOn.java:72: ';' expected

}

^

46 errors

-jGRASP wedge2: exit code for process is 1.

-jGRASP: operation complete.

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

class LogOnextends JPanel{

privatestatic JTextField username=null;

privatestatic JPasswordField password=null;

privatestatic JButton button1=null;

privatestatic JButton button2=null;

String[] username=new String[11];

username[0]="Administrator";

username[1]="Ann Smyth";

username[2]="John Murphy";

username[3]="James McFadden";

username[4]="Frankie Ferry";

username[5]="Daniel McKimm";

username[6]="Stephen Doohan";

username[7]="James Ferry";

username[8]="Liam Cannon";

username[9]="Ciaran Ferry";

username[10]="Ciaran McGee";

String[] password=new String[11];

password[0]="0";

password[1]="1";

password[2]="2";

password[3]="3";

password[4]="4";

password[5]="5";

password[6]="6";

password[7]="7";

password[8]="8";

password[9]="9";

password[10]="10";

public LogOn(){

setSize(260,160);

username=new JTextField(15);

password=new JPasswordField(15);

JLabel usernameLabel=new JLabel("Username: ");

JLabel passwordLabel=new JLabel("Password: ");

add(usernameLabel);

add(username);

add(passwordLabel);

add(password);

setVisible(true);

button1=new JButton("Ok");

add(button1);

button2=new JButton("Cancel");

add(button2);

JFrame frame=new JFrame("Welcome to Home Entertainment");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.add(this);

frame.pack();

frame.setVisible(true);

}

button1.addActionListener(new ActionListener(){

publicvoid actionPerformed(ActionEvent e){

try{

Demo d =new Demo();

d.getChoice();

}

catch(Exception ex){}

}

}

button2.addActionListener(new ActionListener(){

publicvoid actionPerformed(ActionEvent e){

System.exit(0);

}

}

}

[8557 byte] By [james-mcfaddena] at [2007-11-27 1:47:32]
# 1
Assign the values inside the constructorie.public LogOn(){username[0]="Administrator";etc.You're also missing the closing ); when you're adding the actionListeners to the buttons
Balmarka at 2007-7-12 1:10:28 > top of Java-index,Java Essentials,Java Programming...
# 2

1. You initialize your array before your constructor.

2. You have the same names for your arrays as for your TextFields

3. You did not close your anon Listeners.

...

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class MyLogOnScreen extends JPanel{

private static JTextField username=null;

private static JPasswordField password=null;

private static JButton button1=null;

private static JButton button2=null;

String[] usernameArray=new String[11];

String[] passwordArray=new String[11];

public MyLogOnScreen(){

usernameArray[0]="Administrator";

usernameArray[1]="Ann Smyth";

usernameArray[2]="John Murphy";

usernameArray[3]="James McFadden";

usernameArray[4]="Frankie Ferry";

usernameArray[5]="Daniel McKimm";

usernameArray[6]="Stephen Doohan";

usernameArray[7]="James Ferry";

usernameArray[8]="Liam Cannon";

usernameArray[9]="Ciaran Ferry";

usernameArray[10]="Ciaran McGee";

passwordArray[0]="0";

passwordArray[1]="1";

passwordArray[2]="2";

passwordArray[3]="3";

passwordArray[4]="4";

passwordArray[5]="5";

passwordArray[6]="6";

passwordArray[7]="7";

passwordArray[8]="8";

passwordArray[9]="9";

passwordArray[10]="10";

setSize(260,160);

username=new JTextField(15);

password=new JPasswordField(15);

JLabel usernameLabel=new JLabel("Username: ");

JLabel passwordLabel=new JLabel("Password: ");

add(usernameLabel);

add(username);

add(passwordLabel);

add(password);

setVisible(true);

button1=new JButton("Ok");

add(button1);

button2=new JButton("Cancel");

add(button2);

JFrame frame=new JFrame("Welcome to Home Entertainment");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.add(this);

frame.pack();

frame.setVisible(true);

button1.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

try{

Demo d = new Demo();

d.getChoice();

}

catch(Exception ex){}

}

});

button2.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

System.exit(0);

}

});

}

}

abillconsla at 2007-7-12 1:10:28 > top of Java-index,Java Essentials,Java Programming...
# 3

hello.

this is james mcfadden. thanks for the reply. that was a nice program that you gave me. i am now trying to create a logoff screen in java (the LogOff.java program is shown below). it compiles ok, but when i run it i get the following message in the jGRASP compiler window:

-jGRASP exec: java LogOff

java.lang.NoSuchMethodError: main

Exception in thread "main"

-jGRASP wedge2: exit code for process is 1.

-jGRASP: operation complete.

how do i get to display the LogOff GUI on the computer?

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class LogOff extends JPanel{

private static JButton button1=null;

private static JButton button2=null;

public LogOff(){

setSize(260,160);

button1=new JButton("Ok");

add(button1);

button2=new JButton("Cancel");

add(button2);

JFrame frame=new JFrame("Log Off");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.add(this);

frame.pack();

frame.setVisible(true);

button1.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

try{

Demo d = new Demo();

d.getChoice();

System.exit(0);

}

catch(Exception ex){}

}

});

button2.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

System.exit(0);

}

});

}

}

james-mcfaddena at 2007-7-12 1:10:28 > top of Java-index,Java Essentials,Java Programming...
# 4
You need a main method to run a class by itself. You're missing that method (these are very basic things, you shouldn't be doing swing if you don't know how to make a main method).
-Kayaman-a at 2007-7-12 1:10:28 > top of Java-index,Java Essentials,Java Programming...
# 5
hello. this is james mcfadden. thanks for the reply. i don't need to have a main method in the LogOff.java program because an instance of the LogOff class is created in another program called Demo.java.
james-mcfaddena at 2007-7-12 1:10:28 > top of Java-index,Java Essentials,Java Programming...
# 6

then your main method should call the login screen you created, like this:

public static void main (String args[])

{

new /*loginscreenname*/()

}

hunter71485a at 2007-7-12 1:10:28 > top of Java-index,Java Essentials,Java Programming...
# 7
"this is james mcfadden. thanks for the reply. that was a nice program that you gave me. "You are welcome. Why not distribute the [url #" style="display: block; background-image:url(' http://developers.sun.com/forums/img/gold-star.gif'); width: 17px; height: 17px] [/url]
abillconsla at 2007-7-12 1:10:28 > top of Java-index,Java Essentials,Java Programming...