Column of JLabels?

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Stevey - 19 Apr 2005 19:15 GMT

How do I build a column of JLabels?

When a user performs a certain event I want to add a new JLabel to a
suitable container which will display them as a vertical column of JLabels
(i.e. a list).

I tried using a JPanel with BoxLayout and with GridLayout, but for some
reason I can't get them to add an element when the event is performed. I can
get the JPanel to add if I use FlowLayout but this does not look how I want
it to be (as the JLabels append horizontally).

Any suggestions?

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Daniel Dyer - 19 Apr 2005 19:18 GMT

> How do I build a column of JLabels?
>
[quoted text clipped - 9 lines]
> want
> it to be (as the JLabels append horizontally).

Are you remembering to call revalidate() on the container after you add
the new label?

Are you declaring the GridLayout to have a variable number of rows
(http://java.sun.com/j2se/1.5.0/docs/api/java/awt/GridLayout.html#GridLayout(int,
int))?

Are you sure that a JList (perhaps with a custom renderer) wouldn't be
more appropriate?

Dan.

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Daniel Dyer
http://www.footballpredictions.net

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Stevey - 19 Apr 2005 19:32 GMT

>> How do I build a column of JLabels?
>>
[quoted text clipped - 12 lines]
> Are you remembering to call revalidate() on the container after you add
> the new label?

I wasn't, but I am now. Doesn't appear to make any difference.

> Are you declaring the GridLayout to have a variable number of rows
> (http://java.sun.com/j2se/1.5.0/docs/api/java/awt/GridLayout.html#GridLayout(int,
> int))?

Yeah.

pnl_old_questions.setLayout(new GridLayout(0,1));

With the above code it just doesn't seem to add the components to
pnl_old_questions (well it does when I initially set up the display, but not
when the user performs an action). However if I change the above code to
FlowLayout it adds components fine (but looks wrong). Same problem with
BoxLayout.

> Are you sure that a JList (perhaps with a custom renderer) wouldn't be
> more appropriate?

Fairly sure... the purpose of the list is purely to display a kind of 'log'
of the user's actions, not take in any further input from the user based on
this list.

Thanks for the suggestions.

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Arnaud Berger - 20 Apr 2005 08:05 GMT

Hi,

This is a sample you may use :

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

public class AddLabels {

public static void main(String[] args) {

JFrame frame =new JFrame();
frame.setSize(200,200);

Container cont=frame.getContentPane();
cont.setLayout(new BorderLayout());
JPanel buttonPanel=new JPanel();
final JPanel labelsPanel=new JPanel();

/* GridLayout should also work */
/*labelsPan.setLayout(new GridLayout(0,1));*/
labelsPanel.setLayout(new BoxLayout(labelsPanel,BoxLayout.Y_AXIS));

JButton addLabel=new JButton("add");

addLabel.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent arg0) {
labelsPanel.add(new JLabel("one label"));
labelsPanel.revalidate();
}});

buttonPanel.add(addLabel);
cont.add(buttonPanel,BorderLayout.NORTH);
/* a scrollPane to scroll when the number of labels doesn't fit the
panel */
cont.add(new JScrollPane(labelsPanel),BorderLayout.CENTER);

frame.setVisible(true);
}
}

Regards,

Arnaud

> >> How do I build a column of JLabels?
> >>
[quoted text clipped - 16 lines]
>
> > Are you declaring the GridLayout to have a variable number of rows

(http://java.sun.com/j2se/1.5.0/docs/api/java/awt/GridLayout.html#GridLayout
(int,

> > int))?
>
[quoted text clipped - 16 lines]
>
> Thanks for the suggestions.

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Column of JLabels?

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