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javaswingjlabellayout-managerboxlayout

BoxLayout adding left margin

I've got a JPanel that has a BoxLayout (Page axis), and I want to lay out two components, one on top of the other.

enter image description here

My problem is the margin to the left of the large lipsum box, how can I get rid of this? If I don't add the top components, there is no margin.

enter image description here

Here's my code, the second image is created by not adding headerPanel:

JLabel commandLabel = new JLabel(command);
    JLabel paramLabel = new JLabel(params);
    JLabel descLabel = new JLabel("<html><body style='width: 200px;'>" + description + "</body></html>");
    Font baseFont = commandLabel.getFont(), commandFont, paramFont, descFont;

    commandFont = baseFont.deriveFont(Font.BOLD);
    paramFont = baseFont.deriveFont(Font.ITALIC);
    descFont = baseFont.deriveFont(Font.PLAIN);

    commandLabel.setFont(commandFont);
    paramLabel.setFont(paramFont);
    descLabel.setFont(descFont);
    descLabel.setAlignmentX(LEFT_ALIGNMENT);
    descLabel.setBorder(BorderFactory.createStrokeBorder(new BasicStroke()));   
    JPanel headerPanel = new JPanel(new FlowLayout(FlowLayout.LEADING));
        headerPanel.add(commandLabel);
        headerPanel.add(paramLabel);
    this.add(headerPanel);
    this.add(descLabel);

This class extends JPanel, and is added to a JFrame, which is simply pack()'d

Solution

  • Though I couldn't tell where the observed behaviour comes from, the expected display could be achieved by using an intermediate JPanel to contain your label, rather than adding the JLabel directly :

        JLabel commandLabel = new JLabel(command);
    JLabel paramLabel = new JLabel(params);
    JLabel descLabel = new JLabel("<html><body style='width: 200px;'>" + description + "</body></html>");
    Font baseFont = commandLabel.getFont(), commandFont, paramFont, descFont;

    commandFont = baseFont.deriveFont(Font.BOLD);
    paramFont = baseFont.deriveFont(Font.ITALIC);
    descFont = baseFont.deriveFont(Font.PLAIN);

    commandLabel.setFont(commandFont);
    paramLabel.setFont(paramFont);
    descLabel.setFont(descFont);
    descLabel.setAlignmentX(LEFT_ALIGNMENT);
    descLabel.setBorder(BorderFactory.createStrokeBorder(new BasicStroke()));   
    JPanel headerPanel = new JPanel(new FlowLayout(FlowLayout.LEADING));
    JPanel descPanel = new JPanel(new FlowLayout(FlowLayout.LEADING));// added
    headerPanel.add(commandLabel);
    headerPanel.add(paramLabel);

    descPanel.add(descLabel);// added

    this.add(headerPanel);
    this.add(descPanel);// modified