How do I add a margin outside the border of a component in Swing?

Question

I use multiple components that has a border painted. Is there any easy way to add a margin to the component so that the borders aren't painted so close to eachother?

Answer 1

This is typically done using your layout manager. For example, if you are using GridBagLayout, you would set insets on the GridBagConstraint object to the desired value.

Another option is to use the Box object and add a horizontal or vertical struct. See javadoc for Box.createVerticalStrut( int width ) and the similar createHorizontalStrut.

Answer 2

Another way to get what you want is to:

1. get the current Border of your component
2. if null, set an EmptyBorder for your component
3. if not null, create a new CompoundBorder (with an EmptyBorder and the current Border of the component) and set it for the component

In code, that should look like that (sorry I haven't tested it):

Border current = component.getBorder();
Border empty = new EmptyBorder(top, left, bottom right);
if (current == null)
{
    component.setBorder(empty);
}
else
{
    component.setBorder(new CompoundBorder(empty, current));
}

Where:

• component is the Swing component to which you want to add a margin
• top, left, bottom, right are the pixels amounts you want to add around your component

Note that this method might have an impact (size, alignment) on the form layout, depending on the LayoutManager you are using. But I think it is worth trying.