Automate sizing of NodeSelector JComboBox

openlcb / OpenLCB_Java

A git-managed copy of the SVN-based Java prototype implementation of OpenLCB. This implementation operates inside JMRI.

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Automate sizing of NodeSelector JComboBox #216

Closed bobjacobsen closed 1 year ago

bobjacobsen commented 1 year ago

This changes the handling of the JComboBox in org.openlcb.swing.NodeSelector so that it automatically sizes itself to the largest selection string available when the NodeSelector is created.

If there are no known nodes, a default of 70 spaces wide it used
The JComboBox does not resize if additional nodes are discovered after it's been created to prevent the GUI from moving around spontaneously.

balazsracz commented 1 year ago

I don't see any code to resize the combo box when there are nodes. The only code seems to be active when node count == 0. So how does this work?

bobjacobsen commented 1 year ago

A JComboBox by default has a preferred size that will hold its longest content. That's used by a pack() call during layout, so it'll be that size unless there are external constraints.

The previous code was overriding that behavior by always by setting a manual size. I removed that to allow the default behavior to work, setting it specifically only when there isn't any content. That's needed because the default-no-content size is 20 characters, smaller than our typical identifiers.