JComponent InputMap mysteriously getting wiped

Question

I've added bindings to a JComponent's input map, by modifying the map returned by jCompInstance.getInputMap().

The first time I hit a key which I've binded, it works fine. Somehow, thereafter, the InputMap gets wiped. What I mean by this is jCompInstance.getInputMap().size() returns 0.

I apologise for not offering a minimalistic code example which reproduces the problem; attempts to reduce my huge program have been futile.

What might be going on here?

Is there a way for me to set a watchpoint (in Eclipse) of the JComponent's internal InputMap to investigate how this may be occurring?

Thanks in advance!

Answer 1

A failed attempt to reproduce the problem is frustrating, but always worthwhile: it implies that your essential approach to key bindings is likely sound, and a reference example will guide your search for the problem.

Recall that each component's UI delegate is responsible for establishing its key bindings. At a guess, you might check several related things:

• Ensure that Swing GUI objects are constructed and manipulated only on the event dispatch thread in the desired order, as suggested here.

• Verify correct use of UIManager.setLookAndFeel(); in particular, don't use it as a substitute for validate().

• In a custom component, override updateUI() to apply any custom bindings, as shown here for colors.