CODEWITHSUNDEEP
javaswingkey-bindings
Ky6000
Ky6000

Reputation: 103

Keybindings not working - swing

I have been trying to make a small program that prints messages when the user presses a key, however it doesn't print the message. The following is my code:

    public static void key() {
    Main main = new Main();
    JFrame frame = new JFrame();
    JComponent component = frame.getRootPane();
    frame.getContentPane().add(main);
    System.out.println("adad");

    Action test = new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            System.out.println("w has been pressed");
        }
    };
    component.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0),"test");
    component.getActionMap().put("test", test);

}

There are no errors but when the "w" key is pressed actionPerformed isn't called. What am I doing wrong? I don't know if this is relevant, but here is the main method, maybe i'm doing something wrong here.

    public static void main(String[] args) {

    Main main = new Main();
    JFrame frame = new JFrame();
    frame.add(main);
    frame.pack();
    frame.setTitle("Test");
    frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
    frame.setResizable(false);
    frame.setLayout(new BorderLayout());
    key();
    frame.setVisible(true);
    frame.add(frame, BorderLayout.CENTER);
}

Upvotes: 0

Views: 252

Answers (1)

MadProgrammer
MadProgrammer

Reputation: 347334

You've created a second frame which is not visible on the screen, which the key bindings are bound too...

As I said yesterday, the key bindings must be registered with a component which is attached to a displayable component (one which is attached to a native peer) before they will work

If you try using something more like...

public static void key(JComponent component) {
    Action test = new AbstractAction() {
        public void actionPerformed(ActionEvent e) {
            System.out.println("w has been pressed");
        }
    };
    component.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_W, 0), "test");
    component.getActionMap().put("test", test);

}

and pass either the instance of JFrame or one of it's child components (like main or the contentPane) from your public static void main(...) method, it should work

Upvotes: 2

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