Keyboard Input with swing Java

Question

I am working a calculator using java swing and I want to be able to enter the numbers and operations via keyboard. I can\'t seem to get it working.

import java.         


        

Answer 1

I think here is the problem:

button[0].getInputMap().put(...);

From JComponent.getInputMap() javadoc:

Returns the InputMap that is used when the component has focus. This is convenience method for getInputMap(WHEN_FOCUSED).

So the button must have the focus to properly work. Since you're doing a calculator I'd suggest you use this instead:

button[0].getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(...);

JComponent.getInputMap(int condition):

Returns the InputMap that is used during condition.

Parameters:

condition - one of WHEN_IN_FOCUSED_WINDOW, WHEN_FOCUSED, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT