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Hi. I'm designing a Wheel-of-Fortune kind of layout using JButtons
with ActionListeners to guess letters for words (kind of like Hangman,
but using JButtons). I've set up a for loop that gives me 26 JButtons,
but right now, all 26 buttons display "A". Can anyone tell me how to
add an increment function to this so that each button will display a
different letter of the alphabet?

Here is what I have so far:


import javax.swing.*;
import java.awt.*;

public class GhostGUITwo extends JFrame {
public static void main(String args[]) {
new GhostGUITwo();
}
//FRAME
public GhostGUITwo() {
this.setSize(800,600);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );
this.setTitle("Ghost");
this.setLocationRelativeTo(null);
GhostGUITwoPanel panel = new GhostGUITwoPanel();
this.getContentPane().add(panel);
this.setVisible(true);
}
//PANEL
public class GhostGUITwoPanel extends JPanel {
public GhostGUITwoPanel() {

for (int i = 0; i < 26; i++)
this.add(new JButton("A"));
}
}
//add JLabel and ActionListener
//JButton ClickMe adds corresponding letter to JLabel
}

On Jul 31, 4:03 pm, glennsno...@hotmail.com wrote:
> this.add(new JButton("A"));

Try

add(new JButton(""+'A'+i));

This works in C; less sure about Java. There's also:

add(new JButton(LETTERS[i]));

with elsewhere in the class the field

private static final String[] LETTERS = {"A","B","C",...,"Z"};

with the ... filled in in the obvious manner.

The array method is more amenable to any subsequent i18n conversions.

On Tue, 31 Jul 2007 13:03:56 -0700, wrote,
quoted or indirectly quoted someone who said :

> Can anyone tell me how to
>add an increment function to this so that each button will display a
>different letter of the alphabet?

just use a for loop:

for ( char letter= 'A'; letter <= 'Z'; letter++ )

In Unicode you can count on the letters being in order and contiguous.
see http://mindprod.com/jgloss/unicode.html
--
Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

On Tue, 31 Jul 2007 20:16:37 -0000, Twisted <>
wrote, quoted or indirectly quoted someone who said :

>
>add(new JButton(""+'A'+i));
>
>This works in C; less sure about Java. There's also:

That won't work. The problem is + promotes 'A' to an int. You then
effectively have ""+ 65 which will generate the string "65".

There are a number of related gotchas. See
http://mindprod.com/jgloss/gotchas.html#CONCATENATION
--
Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

On Tue, 31 Jul 2007 20:16:37 +0000, Twisted wrote:

> On Jul 31, 4:03 pm, glennsno...@hotmail.com wrote:
>> this.add(new JButton("A"));
>
> Try
>
> add(new JButton(""+'A'+i));
>
> This works in C; less sure about Java. There's also:

The correct form is add(new JButton(""+(char)('A'+i)));

What you wrote would (I think) give you "A0","A1", etc.

On Jul 31, 4:25 pm, Roedy Green <see_webs...@mindprod.com.invalid>
wrote:
> On Tue, 31 Jul 2007 20:16:37 -0000, Twisted <twisted...@gmail.com>
> wrote, quoted or indirectly quoted someone who said :
>
>
>
> >add(new JButton(""+'A'+i));
>
> >This works in C; less sure about Java. There's also:
>
> That won't work. The problem is + promotes 'A' to an int. You then
> effectively have ""+ 65 which will generate the string "65".

Yeah, I figured it might need a cast in there somewhere.

On Jul 31, 4:22 pm, Roedy Green <see_webs...@mindprod.com.invalid>
wrote:
> On Tue, 31 Jul 2007 13:03:56 -0700, glennsno...@hotmail.com wrote,
> quoted or indirectly quoted someone who said :
>
> > Can anyone tell me how to
> >add an increment function to this so that each button will display a
> >different letter of the alphabet?
>
> just use a for loop:
>
> for ( char letter= 'A'; letter <= 'Z'; letter++ )

Java lets you use something other than "int" as a loop counter? I
thought it mostly just errored out at compile time if you tried that
type of thing, and most code I've seen to generate character values
numerically either adds a count to a char or looks up characters from
an array.

On Jul 31, 11:59 pm, Twisted <twisted...@gmail.com> wrote:
>
> > just use a for loop:
> > for ( char letter= 'A'; letter <= 'Z'; letter++ )
>
> Java lets you use something other than "int" as a loop counter?

Indeed.

You can even use Objects. For example, before Java 5,
the standard iterator pattern is this:

for(Iterator i = employeeList.iterator(); i.hasNext(); ) {
Employee x = (Employee) i.next();
...
}

On Tue, 31 Jul 2007 20:22:49 GMT, Roedy Green
<> wrote:

>On Tue, 31 Jul 2007 13:03:56 -0700, wrote,
>quoted or indirectly quoted someone who said :
>
>> Can anyone tell me how to
>>add an increment function to this so that each button will display a
>>different letter of the alphabet?
>
>just use a for loop:
>
>for ( char letter= 'A'; letter <= 'Z'; letter++ )
>
>In Unicode you can count on the letters being in order and contiguous.
>see http://mindprod.com/jgloss/unicode.html
and then

add(new JButton(String.valueOf(letter));

Jim

On Jul 31, 8:13 pm, JackT <jackt...@gmail.com> wrote:
> You can even use Objects. For example, before Java 5,
> the standard iterator pattern is this:

[snip]

Yes, of course I'm familiar with that. I just seem to recall it
balking on most primitive types other than "int", or at least throwing
off a torrent of warnings. C compilers usually also warn, at least on
use of char as a loop index. Which was exactly what was suggested
here.

And I'm fairly sure Java does choke on just about anything but "int"
for an array index, although that's moot if you don't use the loop
counter as an array index or do cast it to int. It definitely doesn't
permit longs as array indices.