java - 如何绑定(bind)命令-？作为帮助菜单的 Swing Action 加速器？

Question

帮助的标准组合键是 command-? 在 mac 上。如何将此组合键绑定(bind)到菜单项。

注意:由于我们的用户有不同的键盘布局，我正在寻找一种不需要了解什么键“？”的解决方案。位于。

使用 KeyStroke.getKeyStroke(String)，javadoc 说；

Parses a string and returns a `KeyStroke`. The string must have the following syntax:

<modifiers>* (<typedID> | <pressedReleasedID>)

modifiers := shift | control | ctrl | meta | alt | button1 | button2 | button3
typedID := typed <typedKey>
typedKey := string of length 1 giving Unicode character.
pressedReleasedID := (pressed | released) key
key := KeyEvent key code name, i.e. the name following "VK_".

我有这个示例代码:

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

public class HelpShortcut extends JFrame {

    public HelpShortcut(){
        // A few keystrokes to experiment with
        //KeyStroke keyStroke = KeyStroke.getKeyStroke("pressed A");    // A simple reference - Works
        //KeyStroke keyStroke = KeyStroke.getKeyStroke("typed ?");      // Works
        KeyStroke keyStroke = KeyStroke.getKeyStroke("meta typed ?");   // What we want - Does not work

        // If we provide an invalid keystroke we get a null back - fail fast
        if (keyStroke==null) throw new RuntimeException("Invalid keystroke");

        // Create a simple menuItem linked to our action with the keystroke as accelerator
        JMenuItem helpMenuItem = new JMenuItem(new HelpAction());
        helpMenuItem.setAccelerator(keyStroke);

        // Install the menubar with a help menu
        JMenuBar mainMenu = new JMenuBar();
        JMenu helpMenu = new JMenu("Help");
        helpMenu.add(helpMenuItem);
        mainMenu.add(helpMenu);

        setJMenuBar(mainMenu);
    }

    // Scaffolding
    public static void main(String[] pArgs) {
        HelpShortcut helpShortcut= new HelpShortcut();
        helpShortcut.setLocationRelativeTo(null);
        helpShortcut.setSize(new Dimension(100, 162));
        helpShortcut.setVisible(true);
    }

    private class HelpAction extends AbstractAction {

        public HelpAction() {
            putValue(Action.NAME,"Help me!");

        }

        @Override
        public void actionPerformed(final ActionEvent pActionEvent) {
            JOptionPane.showMessageDialog(HelpShortcut.this,"You should ask StackOverflow!");
        }

    }
}

Answer 1

在我的键盘上“？”位于“/”键上方，因此您还可以在旁边使用 shift 键键入“?”。所以要进行绑定(bind)，您需要使用:

// KeyStroke keyStroke = KeyStroke.getKeyStroke("meta typed ?");
int modifier = Toolkit.getDefaultToolkit().getMenuShortcutKeyMask() 
             + KeyEvent.SHIFT_DOWN_MASK;
KeyStroke keyStroke = KeyStroke.getKeyStroke(KeyEvent.VK_SLASH, modifier);