从面板中删除键侦听器

Question

有可能清除我放在我身上的听众JPanel吗？当我调用一个方法时,我KeyListener在面板上放了一个但是当我退出这个方法时,我想清除那个监听器.

这是我的方法:

private void stopBall(final Graphics2D g2, int posBallY, String winner) {

        move = false;
        scorePanel.showPressSpace(true);    

        setFocusable(true);
        requestFocus();

        addKeyListener(new KeyAdapter() {

            public void keyPressed(KeyEvent e){  
                if (e.getKeyCode() == KeyEvent.VK_SPACE){ 

                    setPosX(getPlayPanelWidth()/2);
                    setPosY(0);

                    move = true;
                    scorePanel.showPressSpace(false);
                    initBall(g2);
                } 

            }});

        if (winner == "player1") {
            scoreCountPlayer1++;
            scorePanel.getLab_Player1().setText("" + scoreCountPlayer1);


        } else if (winner == "comp") {
            scoreCountComputer++;
            scorePanel.getLab_Computer().setText("" + scoreCountComputer);
        }   
    }

Answer 1

你对addKeyListener(KeyListener)有一个非限定的调用,所以我假设你已经扩展了JPanel.如果是这样,那么你可以调用removeKeyListener(KeyListener).在您当前的代码中,您的密钥监听器是匿名的.您需要稍微更改它以保持该引用,如下所示:

// Create a variable holding the listener
KeyAdapter keyAdapter = new KeyAdapter()
{
  public void keyPressed(KeyEvent e)
  {
    if (e.getKeyCode() == KeyEvent.VK_SPACE)
    {
      setPosX(getPlayPanelWidth() / 2);
      setPosY(0);

      move = true;
      scorePanel.showPressSpace(false);
      initBall(g2);
    }

  }
};
// Register the listener with this JPanel
addKeyListener(keyAdapter);

// Time passes...

// Remove the listener from this JPanel
removeKeyListener(keyAdapter);