KeyListener Only Sometimes Works

Question

I have made a Pong clone, and I've come across a problem. The KeyListener only works sometimes. There is no pattern that I have been able to find.

For reference here is my Pong.java(the main class): http://pastebin.com/8d7BqK4x

Here is the Board.java(Graphics and KeyListener): http://pastebin.com/0zb526BE

Why are you reposting this question? You already got this same answer when you asked this question yesterday! http://stackoverflow.com/questions/7940173/how-do-i-use-keyeventdispatcher — camickr, Oct 31 '11 at 00:56

score 3 · Answer 1 · answered Oct 31 '11 at 00:42

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KeyEvents are only generated when a component has focus.

A better approach is to use Key Bindings which work even when the component doesn't have focus.

answered Oct 31 '11 at 00:42

camickr

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score 2 · Accepted Answer · answered Oct 31 '11 at 00:43

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Usually you don't want to use a KeyListener due to focus issues (which is likely why your listener only listens at times -- likely your listen-to component loses focus and so the KeyListener loses its function.

Better to use Key Bindings where you don't have to worry so much about focus issues and where you're dealing with a higher level construct, one that Swing uses itself to listen to components. The tutorials will "show you the way".

answered Oct 31 '11 at 00:43

Hovercraft Full Of Eels

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@Cg2916 again same result as from http://stackoverflow.com/questions/7940173/how-do-i-use-keyeventdispatcher/7940227#7940227 – mKorbel Oct 31 '11 at 06:07

KeyListener Only Sometimes Works

2 Answers2