BoxLayout alignment issue

[Shannon Sims]

Hello,
Can someone please explain why my JPanel ( labelPanel - JLables: "One Two Three" ) with a BoxLayout will not align the components to the left instead of the center?

package learn.swing;
 
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
 
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
 
public class MultiplePanels extends JDialog{
public MultiplePanels(){
super( new JFrame() );
this.setTitle( "Multiple Panels" );
this.setModal( true );
this.buildWindow();
this.setVisible( true );
}
 
private void buildWindow() {
//align all panel top to bottom
        Container pane = this.getContentPane();
        pane.setLayout( new BoxLayout( pane, BoxLayout.Y_AXIS ) );
        
        //align JLabel top to bottom
        JPanel lablePanel = new JPanel();
        lablePanel.setLayout( new BoxLayout( lablePanel, BoxLayout.Y_AXIS ) );
        
        //align JLabel and Input left to left
        JPanel inputPanel = new JPanel();
        inputPanel.setLayout( new FlowLayout( FlowLayout.LEFT ) );
        
        //centering buttons
        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout( new FlowLayout( FlowLayout.CENTER ) );
 
        this.buildLabels( lablePanel );
        this.buildInput( inputPanel );
        this.buildButtons( buttonPanel );
        
        pane.add( lablePanel );
        pane.add( inputPanel );
        pane.add( buttonPanel );
 
        this.setSize( 800, 800 );
        this.setContentPane( pane );
        this.pack();
        this.setDefaultCloseOperation( JFrame.DISPOSE_ON_CLOSE );
}
 
private void buildLabels( JPanel panel ){
        JLabel labelOne = new JLabel( "One" );
        JLabel labelTwo = new JLabel( "Two" );
        JLabel labelThree = new JLabel( "Three" );
        
        panel.add( Box.createRigidArea(new Dimension(0,5)) );
        panel.add( labelOne );
        panel.add( labelTwo );
        panel.add( labelThree );
}

private void buildInput( JPanel panel ) {
        JLabel numberLabel = new JLabel( "Enter a Number: " );        
        JTextField aNumber = new JTextField(7);
 
        panel.add( numberLabel );
        panel.add( aNumber );
}

private void buildButtons( JPanel panel ) {
JButton okButton = new JButton( "OK" );
        JButton cancelButton = new JButton( "Canel" );
 
        panel.add( okButton );
        panel.add( cancelButton );
}

public static void main(String[] args) {
new MultiplePanels();
// TODO Auto-generated method stub
}
}

Thank you.

[James Swan]

Try experimenting with setAlignmentX(java.awt.Component.LEFT_ALIGNMENT) on your labels.

[Ken Blair]

Originally posted by James Swan:
Try experimenting with setAlignmentX(java.awt.Component.LEFT_ALIGNMENT) on your labels.

Bingo. You must set them all to have a left alignment. I don't know JLabel sizing properties off the top of my head so it's possible the JLabel will actually expand and set the text in the center. If the above doesn't work try setHorizotnalAlignment(int) to set the text position.

[Michael Dunn]

do you need to use a BoxLayout?

if you change
lablePanel.setLayout( new BoxLayout( lablePanel, BoxLayout.Y_AXIS ) );
to
lablePanel.setLayout( new java.awt.GridLayout( 0,1 ) );

and then this as your buildLabels()

  private void buildLabels( JPanel panel )  {
        JLabel labelOne = new JLabel( "One" ,JLabel.LEFT);
        JLabel labelTwo = new JLabel( "Two" ,JLabel.LEFT);
        JLabel labelThree = new JLabel( "Three" ,JLabel.LEFT);
 
        //panel.add( Box.createRigidArea(new Dimension(0,5)) );
        panel.add( labelOne );
        panel.add( labelTwo );
        panel.add( labelThree );
  }
 

[Shannon Sims]

Hello again,
Thanks for the great feedback, however setting the alignment on the JLabel didn't seem to work.

Originally posted by Ken Blair:

Bingo. You must set them all to have a left alignment. I don't know JLabel sizing properties off the top of my head so it's possible the JLabel will actually expand and set the text in the center. If the above doesn't work try setHorizotnalAlignment(int) to set the text position.

Using the GridLayout worked but just a minor problem using this Layout, the JLables are right on the left frame. I know this seems picky, but presentation is important especially when I'm being graded. Gosh, something that seems so simple can be so hard in SWING. Ugh!

Well, I guess worse case scenario, I could use the GridLayout.

Thank again!

[Michael Dunn]

> the JLables are right on the left frame

labelOne.setBorder(javax.swing.BorderFactory.createEmptyBorder(0,10,0,0));

will nudge it in a bit

[Shannon Sims]

Yee haw, that did it! Thanks Michael...gosh how do you learn this stuff!?!? It's so difficult figuring out what works with what...

Originally posted by Michael Dunn:
> the JLables are right on the left frame

labelOne.setBorder(javax.swing.BorderFactory.createEmptyBorder(0,10,0,0));

will nudge it in a bit

Thanks again!

[Ken Blair]

Originally posted by Shannon Sims:
Hello again,
Thanks for the great feedback, however setting the alignment on the JLabel didn't seem to work.

Did you set the alignment of all of them? You may need to set the alignment of the Box itself too. Alignments do strange things, I never have been able to get an answer on why they come out the way they do. All anyone has ever been able to do is tell me the effect, never the actual root cause. "You have to set them all to 0.0" but never the why the hell Java needs them all to be 0.0, for example.

[Shannon Sims]

Hi Ken,
Sorry about the delay in response. Yes, I set the alignment on each JLabel and the alignment on the Box was set when I "newed" the Box, without much success. Since using the BoxLayout wasn't mandatory, I used Michael's solution instead.

Thanks for your help, I really appreciate it!