JSeparator wont show with GridBagLayout

Question

I want to add a vertical JSeparator between two components using a GridBagLayout. The code I have is as follows:

public MainWindowBody(){
    setLayout(new G         


        

Answer 1

You could try to set the preferred width for the separator:

sep.setPreferredSize(new Dimension(5,1));

Then, make GridBagLayout use up all available height for the separator:

gbc.fill = GridBagConstraints.VERTICAL;
gbc.weighty = 1;

Answer 2

Taken from Sun's guide for JSeparator:

In most implementations, a vertical separator has a preferred height of 0, and a horizontal separator has a preferred width of 0. This means a separator is not visible unless you either set its preferred size or put it in under the control of a layout manager such as BorderLayout or BoxLayout that stretches it to fill its available display area.

The vertical separator does have a bit of width (and the horizontal a bit of height), so you should see some space where the separator is. However, the actual dividing line isn't drawn unless the width and height are both non-zero.

Maybe you should set right constraints?