Java 事件 KeyPress 键盘

Question

我有这门课。这个类绘制了 3 个按钮，并且每个按钮都有一个关联的事件。我需要为键盘创建一个事件，按下一个键与按下其中一个按钮相同。这是我的课:

public class ShapedDialog extends JDialog implements KeyListener, ActionListener {

private final MainWindow parent;

public ShapedDialog(MainWindow parent, String title) {
    super(parent, title, true);
    this.parent = parent;

    if (parent != null) {
        Dimension parentSize = parent.getSize();
        Point p = parent.getLocation();
        setLocation(p.x + parentSize.width / 4, p.y + parentSize.height / 4);
    }

    JPanel messagePane = new JPanel();
    messagePane.add(new JLabel());
    getContentPane().add(messagePane);

    JPanel buttonPane = new JPanel();

    //JButton1
    JButton jButton1 = new JButton();
    try {
        Image img = ImageIO.read(getClass().getResource("logo.png"));
        jButton1.setIcon(new ImageIcon(img));
    } catch (IOException ex) {
    }
    jButton1.addActionListener(new java.awt.event.ActionListener() {
        @Override
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton1ActionPerformed(evt);
        }
    });

    //JButton2
    JButton jButton2 = new JButton();
    try {
        Image img = ImageIO.read(getClass().getResource("logo.png"));
        jButton2.setIcon(new ImageIcon(img));
    } catch (IOException ex) {
    }
    jButton2.addActionListener(new java.awt.event.ActionListener() {
        @Override
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton2ActionPerformed(evt);
        }
    });

    //JButton3
    JButton jButton3 = new JButton();
    try {
        Image img = ImageIO.read(getClass().getResource("logo.png"));
        jButton3.setIcon(new ImageIcon(img));
    } catch (IOException ex) {
    }
    jButton3.addActionListener(new java.awt.event.ActionListener() {
        @Override
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton3ActionPerformed(evt);
        }
    });

    //Add buttons in the panel
    buttonPane.setLayout(new GridLayout(3, 3));
    buttonPane.add(jButton1);
    buttonPane.add(jButton2);
    buttonPane.add(jButton3);

    getContentPane().add(buttonPane, BorderLayout.SOUTH);
    setDefaultCloseOperation(DISPOSE_ON_CLOSE);

    pack();
    setVisible(true);
}

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
    // TODO add your handling code here
    setVisible(false);
    parent.setMyPackage("Type 1");
    dispose();
}

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
    // TODO add your handling code here
    setVisible(false);
    parent.setMyPackage("Type 2");
    dispose();
}

private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
    // TODO add your handling code here
    setVisible(false);
    parent.setMyPackage("Type 3");
    dispose();
}

@Override
public void actionPerformed(ActionEvent e) {
    setVisible(false);
    parent.setMyPackage("Type Package");
    dispose();
}

    public static void main(String[] a) {
        JTextField component = new JTextField();
        component.addKeyListener(new MyKeyListener());

        ShapedDialog dlg = new ShapedDialog((MainWindow) new JFrame(), "title");
    }

    @Override
    public void keyTyped(KeyEvent e) {
        throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public void keyPressed(KeyEvent e) {
        throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public void keyReleased(KeyEvent e) {
        throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
    }

}

class MyKeyListener extends KeyAdapter {
    public void keyPressed(KeyEvent evt) {
        if (evt.getKeyChar() == 'a') {
            System.out.println("Check for key characters: " + evt.getKeyChar());
        }
        if (evt.getKeyCode() == KeyEvent.VK_HOME) {
            System.out.println("Check for key codes: " + evt.getKeyCode());
        }
    }
}

有人可以帮助我吗？

Answer 1

I need to create an event for the keyboard, pressing a key will be the same as pressing one of the buttons.

您需要:

1. 创建一个供每个按钮使用的Action。请参阅How to Use Actions
2. 使用Action创建 JButton
3. 为Action 和KeyStroke 创建按键绑定(bind)。请参阅How to Use Key Bindings

简单的例子:

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

public class CalculatorPanel extends JPanel
{
    private JTextField display;

    public CalculatorPanel()
    {
        Action numberAction = new AbstractAction()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                display.setCaretPosition( display.getDocument().getLength() );
                display.replaceSelection(e.getActionCommand());
            }
        };

        setLayout( new BorderLayout() );

        display = new JTextField();
        display.setEditable( false );
        display.setHorizontalAlignment(JTextField.RIGHT);
        add(display, BorderLayout.NORTH);

        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout( new GridLayout(0, 5) );
        add(buttonPanel, BorderLayout.CENTER);

        for (int i = 0; i < 10; i++)
        {
            String text = String.valueOf(i);
            JButton button = new JButton( text );
            button.addActionListener( numberAction );
            button.setBorder( new LineBorder(Color.BLACK) );
            button.setPreferredSize( new Dimension(50, 50) );
            buttonPanel.add( button );

            KeyStroke pressed = KeyStroke.getKeyStroke(text);
            InputMap inputMap = button.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
            inputMap.put(pressed, text);
            button.getActionMap().put(text, numberAction);
        }
    }

    private static void createAndShowUI()
    {
//      UIManager.put("Button.margin", new Insets(10, 10, 10, 10) );

        JFrame frame = new JFrame("Calculator Panel");
        frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
        frame.add( new CalculatorPanel() );
        frame.pack();
        frame.setLocationRelativeTo( null );
        frame.setVisible(true);
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowUI();
            }
        });
    }
}