How to set the Java default button to react on ENTER key _released_?

Question

In my application I use a Default button. I want it to react when ENTER Key is released. Not when ENTER Key is pressed.

I removed the KeyStroke from InputMap of the button. But it didn't work for me. How should i do that?

---

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;

public class ButtonTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                buildFrame();
            }
        });
    }

    private static void buildFrame() {
        JFrame f = new JFrame("Test");
        f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        JButton button = new JButton(new AbstractAction("Button") {
            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("ButtonTest::actionPerformed: CALLED");
            }
        });

        JButton button2 = new JButton("Button 2");
        InputMap im = button.getInputMap();
        im.put(KeyStroke.getKeyStroke("ENTER"), "none");
        im.put(KeyStroke.getKeyStroke("released ENTER"), "released");

        f.setLayout(new GridBagLayout());
        f.add(button);
        f.add(button2);
        f.getRootPane().setDefaultButton(button);

        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
}

This is the sample code.

Answer 1

JRootPane rootPane = SwingUtilities.getRootPane(/* Your JButton  */); 
rootPane.setDefaultButton(/* Your JButton  */);

Answer 2

the keys for the default button (that is, the button that is triggered on enter, no matter which component is focusOwner) are bound in the rootPane's componentInputMap, that is its inputMap of type WHEN_IN_FOCUSED_WINDOW. So technically, that's the place to tweak:

JComponent content = new JPanel();
content.add(new JTextField("some focusable"));
content.add(new JTextField("something else"));

JXFrame frame = wrapInFrame(content, "default button on released");
Action action = new AbstractAction("do something") {

    @Override
    public void actionPerformed(ActionEvent e) {
        LOG.info("clicked");
    }
};
JButton button = new JButton(action);
content.add(button);
frame.getRootPane().setDefaultButton(button);
// remove the binding for pressed
frame.getRootPane().getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW)
    .put(KeyStroke.getKeyStroke("ENTER"), "none");
// retarget the binding for released
frame.getRootPane().getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW)
    .put(KeyStroke.getKeyStroke("released ENTER"), "press");

Beware: this is still different from the pressed/released behaviour of a non-default button because the rootPane action simply call's button.doClick without going through the moves of arming/pressing the buttonModel to indirectly trigger the action.