如何在java中按Ctrl + z实现撤销

Question

I try to programming a TextEditor. Now I can realize it by adding a button. And I want to realize revoke by pressing Ctrl+Z . How to deal with it ? Please give me some suggestions.

now i can realize it by

jta.addKeyListener(new KeyListener() {

    @Override
    public void keyTyped(KeyEvent e) {
        if((e.getKeyChar() == 0x1a)) {
            if(doManager.canUndo()) {
                doManager.undo();
            }
            System.out.println(1);
        }
    }

    @Override
    public void keyReleased(KeyEvent e) {

    }

    @Override
    public void keyPressed(KeyEvent e) {

    }
});

Why this can't?

jta.addKeyListener(new KeyListener() {

    @Override
    public void keyTyped(KeyEvent e) {
        if((e.getKeyCode() == KeyEvent.VK_Z) && ((e.getModifiers() & KeyEvent.CTRL_MASK) != 0)) {
            if(doManager.canUndo()) {
                doManager.undo();
            }
            System.out.println(1);
        }
    }

    @Override
    public void keyReleased(KeyEvent e) {

    }

    @Override
    public void keyPressed(KeyEvent e) {

    }
});

Why this can't?

jta.addKeyListener(new KeyListener() {

    @Override
    public void keyTyped(KeyEvent e) {
        if((e.getKeyCode() == KeyEvent.VK_Z) && (e.isControlDown() == true)) {
            if(doManager.canUndo()) {
                doManager.undo();
            }
            System.out.println(1);
        }
    }

    @Override
    public void keyReleased(KeyEvent e) {

    }

    @Override
    public void keyPressed(KeyEvent e) {

    }
});

@Felix Gerber

Answer 1

The way to go would be to add an KeyListener to your user interface.

Oracle has an little tutorial about writing an own here .

Here is an little example checking if CRTL+Z is pressed apllied to a JFrame :

    JFrame frame = new JFrame();
    frame.addKeyListener(new KeyListener() {

        @Override
        public void keyTyped(KeyEvent e) {


        }

        @Override
        public void keyReleased(KeyEvent e) {
            // TODO Auto-generated method stub

        }

        @Override
        public void keyPressed(KeyEvent e) {
            if ((e.getKeyCode() == KeyEvent.VK_Z) && ((e.getModifiers() & KeyEvent.CTRL_MASK) != 0)) 
            {
                System.out.println("Your code here!");
            }
        }
    });
    frame.setLocationRelativeTo(null);
    frame.setSize(200, 200);
    frame.setVisible(true);

Answer 2

Thanks everybody!

now i can realize it by

jta.addKeyListener(new KeyListener() {

    @Override
    public void keyTyped(KeyEvent e) {
        if((e.getKeyChar() == 0x1a)) {
            if(doManager.canUndo()) {
                doManager.undo();
            }
        }
    }

    @Override
    public void keyReleased(KeyEvent e) {

    }

    @Override
    public void keyPressed(KeyEvent e) {

    }
});

and

jta.addKeyListener(new KeyListener() {

    @Override
    public void keyTyped(KeyEvent e) {

    }

    @Override
    public void keyReleased(KeyEvent e) {

    }

    @Override
    public void keyPressed(KeyEvent e) {
        if((e.getKeyCode() == KeyEvent.VK_Z) && ((e.getModifiers() & KeyEvent.CTRL_MASK) != 0)) {
            if(doManager.canUndo()) {
                doManager.undo();
            }
        }
    }
});

and

jta.addKeyListener(new KeyListener() {

    @Override
    public void keyTyped(KeyEvent e) {

    }

    @Override
    public void keyReleased(KeyEvent e) {

    }

    @Override
    public void keyPressed(KeyEvent e) {
        if((e.getKeyCode() == KeyEvent.VK_Z) && (e.isControlDown() == true)) {
            if(doManager.canUndo()) {
                doManager.undo();
            }
        }
    }
});