在Jtable中按下重复的向下箭头键

Question

On JTable , when down arrow key is pressed repeatedly, multiple KeyEvents are fired in quick succession. My requirement is that I need to act only on last KeyEvent . I am trying to use TimerTask in KeySelectionListener , but it is giving inconclusive results.

Any idea what changes can be done in KeyListener ?

Sample code -

addKeyListener(new KeyListener() {


        Timer t = new Timer();
        TimerTask tt;


        @Override
        public void keyTyped(KeyEvent e) {

        }

        @Override
        public void keyReleased(KeyEvent e) {

             tt.cancel();
             tt = null;



        }

        @Override
        public void keyPressed(KeyEvent e) {


            if (tt != null)
                return;

            tt = new TimerTask() {
                @Override
                public void run() {

                    System.out.println("Selected-- "+getModel().getValueAt(getSelectedRow(), 2));
                }
            };

           // t.scheduleAtFixedRate(tt, 0, 500);
            t.schedule(tt, 0, 200);



        }
    });

Thanks

Answer 1

The idea with a Timer (and I strongly suggest to use the javax.swing.Timer class since you interact with Swing components) should work.

Just set the repeats to false , start the timer when you receive a keystroke if the timer is not running, or restart the timer when the timer is already running. This will cause a slight delay in the handling of the last key (delay = the delay you set on the timer), but avoid that you react on each key stroke

Answer 2

I used Timer only. I maintained reference of KeyEvent in listener and if another KeyEvent is received in pre-defined delay (for testing kept it 1 sec), new event is referneced. Thus when there is no new keyEvent for 1 sec, last referred event is used for further processing. its working for now. Feel free to suggest your opinions.

addKeyListener(new KeyListener() {

        KeyEvent eventToProcess;
        Timer t = new Timer();
        TimerTask tt;


        @Override
        public void keyTyped(KeyEvent e) {

        }

        @Override
        public void keyPressed(KeyEvent e) {

            if(tt != null){
                tt.cancel();
                tt = null;
            }


        }

        @Override
        public void keyReleased(KeyEvent e) {

            eventToProcess = e;

            tt = new TimerTask() {
                @Override
                public void run() {

                    System.out.println("Selected-- "+getModel().getValueAt(getSelectedRow(), 2)+"  Key Event > "+eventToProcess.getKeyChar());
                }
            };

            t.schedule(tt, 1000);
          }
    });