Add key bindings to JButtons that get their actions from action commands?

Question

I found a cool way in another question to create a JButton whose actions are written and viewed in an easy way:

public JButton makeToolbarButton(String title         


        

Answer 1

I think you're missing the point of the Action API. A Action is intended to provide a single, self contained, unit of work. This means that the actionCommand really isn't required, as when the actionListener event is triggered, you know exactly the context in which it's been executed

I'd also avoid using KeyStroke.getKeyStroke(String), as the text is a verbose description of what you want to do (ie pressed B or something, but needless to say, it's a pain to get right)

So, the following demonstrates how you might use Actions and assign them to a button AND a key binding

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class ActionTest {

    public static void main(String[] args) {
        new ActionTest();
    }

    public ActionTest() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            add(createButton(new ActionOne(), KeyStroke.getKeyStroke(KeyEvent.VK_1, 0)));
            add(createButton(new ActionTwo(), KeyStroke.getKeyStroke(KeyEvent.VK_2, 0)));
        }

        public JButton createButton(Action action, KeyStroke keyStroke) {
            JButton btn = new JButton(action);
            btn.getInputMap(WHEN_IN_FOCUSED_WINDOW).put(keyStroke, "button_pressed");
            btn.getActionMap().put("button_pressed", action);
            return btn;
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            g2d.dispose();
        }

    }

    public class ActionOne extends AbstractAction {

        public ActionOne() {
            putValue(NAME, "1");
            putValue(Action.ACTION_COMMAND_KEY, "Action.one");
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            System.out.println(e.getActionCommand());
        }

    }

    public class ActionTwo extends AbstractAction {

        public ActionTwo() {
            putValue(NAME, "2");
            putValue(Action.ACTION_COMMAND_KEY, "Action.two");
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            System.out.println(e.getActionCommand());
        }

    }

}

See How to Use Actions for more details