Java/Swing Box Layout with Separator

Question

Here is the code:

Box twoPanelBox= new Box(BoxLayout.Y_AXIS);
twoPanelBox.add(panelA); // red
twoPanelBox.add(new JSeparator(SwingConstants.HORIZONTAL) );
twoPanelBox.add(panelB); // black

And here is what i get:

screenshot of panels

The red and the black panel are displayed as expected, where the seperater ( green box around) has something like a margin between.

How can a avoid this marging, and eliminate this space (grey area)? Thank you

What L&F are you using? Try to put `setContentMargin(new Insets(0,0,0,0))` — nachokk, Dec 27 '13 at 14:26
well this is the correct output, (but for other answerers to) for better help sooner post an SSCCE, short, runnable, compilable, just about JFrame with two JPanels and one JSeparator — mKorbel, Dec 27 '13 at 14:32
@nachokk: I'm using W7 standard [UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName())] — MemLeak, Dec 27 '13 at 14:41

score 11 · Accepted Answer · edited Sep 28 '18 at 16:01

11

A little unexpectedly, BoxLayout will stretch the separator. However, this dirty hack will help:

JSeparator separator = new JSeparator(SwingConstants.HORIZONTAL);
separator.setMaximumSize( new Dimension(Integer.MAX_VALUE, 1) );
mergeBox.add(separator);

edited Sep 28 '18 at 16:01

Matthias Braun

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answered Dec 27 '13 at 14:54

MemLeak

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not dirty hack, BoxLayout accepting Min/Max and PreferredSize, JSeparator returns own PreferredSize, but there are another two ways – mKorbel Dec 28 '13 at 20:42

Java/Swing Box Layout with Separator

1 Answers1