key bindings without creating new instance every time

Asked Nov 07 '14 at 19:10

Active Nov 07 '14 at 19:10

Viewed 39 times

checkout the first answer of this post: Java Keybindings especially, these rows:

am.put("RightArrow", new ArrowAction("RightArrow"));
am.put("LeftArrow", new ArrowAction("LeftArrow"));
am.put("UpArrow", new ArrowAction("UpArrow"));
am.put("DownArrow", new ArrowAction("DownArrow"));

he is always creating new object of his class, is it possible to do without it? check my code below, I tried all methods of ActionEvent's variable "e", but all of them were unuseful. Is it good to create every time new object? I have this so far:

action = new AbstractAction() {

        @Override
        public void actionPerformed(ActionEvent e) {
        // can I determine here what action was performed?
        }
    };

    inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_LEFT, 0), "left_arrow");
inputMap.put(KeyStroke.getKeyStroke(KeyEvent.VK_RIGHT, 0), "right_arrow");
    actionMap.put("left_arrow", action);
actionMap.put("right_arrow", action);

edited May 23 '17 at 12:21

Community

asked Nov 07 '14 at 19:10

Pink

try ActionEvent.getActionCommand(). It may or may not differentiate for your "left_arrow" / "right_arrow" events – ControlAltDel Nov 07 '14 at 19:14
I'm getting null from this method. – Pink Nov 07 '14 at 19:14
then there's no way to do it – ControlAltDel Nov 07 '14 at 19:17
IMO it can slack an application a little if there are many bindings using very often or no? – Pink Nov 07 '14 at 19:24

key bindings without creating new instance every time

0 Answers0