禁用单ALT类型激活菜单(Disable single ALT type to activate t

2019-09-28 05:42发布

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我试图禁用Windows查找ALT键的默认行为和感受时，JTextArea是重点和框架安装了JMenu的。 什么默认情况是，菜单获取键盘焦点，因此，你无法继续打字那里。

我的第一次尝试通过将关键的JTextArea的InputMap可以捕获单ALT印刷机： 

//Disable ALT key presses when the textarea is focused
jta.getInputMap(javax.swing.JComponent.WHEN_FOCUSED).put(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_ALT, 0, true), "ALTKEY");
jta.getActionMap().put("ALTKEY", new javax.swing.AbstractAction() {
    private static final long serialVersionUID = 1L;
    @Override
    public void actionPerformed(java.awt.event.ActionEvent e) {
        System.out.println("Performed");
    }
});

我注意到了这个预期一样在一些第三方的虚拟机而不是在从Oracle 1.8.0_211最新

然后我试图使用从AWT组件按键侦听和它到达其他组件之前消耗该事件。 

//Disable ALT key presses when the textarea is focused, second attempt
jta.addKeyListener(new java.awt.event.KeyListener(){
    @Override
    public void keyPressed(KeyEvent e) {
        if(e.getKeyCode() == java.awt.event.KeyEvent.VK_ALT){
            System.out.println("Pressed");
            e.consume();
        }
    }
    @Override
    public void keyReleased(KeyEvent e) {
        if(e.getKeyCode() == java.awt.event.KeyEvent.VK_ALT){
            System.out.println("Released");
            e.consume();
        }
    }
    @Override
    public void keyTyped(KeyEvent e) {
        if(e.getKeyCode() == java.awt.event.KeyEvent.VK_ALT){
            System.out.println("Typed");
            e.consume();
        }
    }
});

没运气。

最后，我试图改变用于创建菜单快捷方式，并完全摆脱恼人ALT行为的关键： 

//Disable the ALT for the Mnemonic and put CTRL:
int[] ints = {java.awt.event.KeyEvent.CTRL_MASK};
javax.swing.UIManager.put("Menu.shortcutKeys", ints);

这避免了使用与ALT键（CTRL非常完美）的快捷方式，但并没有阻止标准的行为，当一个ALT按完成。

更改L＆F到其他平台，或不将其设置为Windows的一个可以解决问题，但当然，它改变了整个程序的外观。

我想我做错了什么，但改变的InputMap或添加KeyListeners工作了第三方虚拟机，所以我开始认为这可能是一个错误。

如何找到谁是听Alt键按下，避免它的任何想法？ 有没有一种方法来定制L＆F或看到什么是它的配置？

下面是测试的完整代码： 

public class JMenubarAltTest extends javax.swing.JFrame{
    private static final long serialVersionUID = 1L;

    public JMenubarAltTest(){
        super();

        //Disable the ALT for the Mnemonic and put CTRL key instead:
        int[] ints = {java.awt.event.KeyEvent.CTRL_MASK};
        javax.swing.UIManager.put("Menu.shortcutKeys", ints);

        //Put the platform L&F, in my case I need this to work in Windows
        try {
            javax.swing.UIManager.setLookAndFeel(javax.swing.UIManager.getSystemLookAndFeelClassName());
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | javax.swing.UnsupportedLookAndFeelException e1) {
            e1.printStackTrace();
        }

        this.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);

        //Create a random menu with some random items
        javax.swing.JMenuBar jmb = new javax.swing.JMenuBar();
        javax.swing.JMenu jm1 = new javax.swing.JMenu("menu1");
        jm1.setMnemonic(java.awt.event.KeyEvent.VK_M);
        jm1.add(new javax.swing.JMenuItem("item1"));
        jm1.add(new javax.swing.JMenuItem("item2"));
        jm1.add(new javax.swing.JMenuItem("item3"));

        javax.swing.JMenu jm2 = new javax.swing.JMenu("menu1");
        jm2.setMnemonic(java.awt.event.KeyEvent.VK_E);
        jm2.add(new javax.swing.JMenuItem("item1"));
        jm2.add(new javax.swing.JMenuItem("item2"));
        jm2.add(new javax.swing.JMenuItem("item3"));

        jmb.add(jm1);
        jmb.add(jm2);
        this.setJMenuBar(jmb);

        //Get a JTextArea to show what happens with the focus
        javax.swing.JTextArea jta = new javax.swing.JTextArea();

        //Disable ALT key presses when the textarea is focused
        jta.getInputMap(javax.swing.JComponent.WHEN_FOCUSED).put(javax.swing.KeyStroke.getKeyStroke(java.awt.event.KeyEvent.VK_ALT, 0, true), "ALTKEY");
        jta.getActionMap().put("ALTKEY", new javax.swing.AbstractAction() {
            private static final long serialVersionUID = 1L;
            @Override
            public void actionPerformed(java.awt.event.ActionEvent e) {
                System.out.println("Performed");
            }
        });

        //Disable ALT key presses when the textarea is focused, second attempt
        jta.addKeyListener(new java.awt.event.KeyListener(){
            @Override
            public void keyPressed(java.awt.event.KeyEvent e) {
                if(e.getKeyCode() == java.awt.event.KeyEvent.VK_ALT){
                    System.out.println("Pressed");
                    e.consume();
                }
            }
            @Override
            public void keyReleased(java.awt.event.KeyEvent e) {
                if(e.getKeyCode() == java.awt.event.KeyEvent.VK_ALT){
                    System.out.println("Released");
                    e.consume();
                }
            }
            @Override
            public void keyTyped(java.awt.event.KeyEvent e) {
                if(e.getKeyCode() == java.awt.event.KeyEvent.VK_ALT){
                    System.out.println("Typed");
                    e.consume();
                }
            }
        });

        this.getContentPane().add(jta);
        this.pack();
        this.setSize(200, 200);
        this.setVisible(true);
    }

    public static void main(java.lang.String[] args){
        new JMenubarAltTest();
    }
}

Answer 1:

可惜的是在Windows L＆F的ALT处理器因为某些原因忽略了消费标志。 因此，我们需要使用反射API将其删除。 

import java.awt.BorderLayout;
import java.awt.KeyEventPostProcessor;
import java.awt.KeyboardFocusManager;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.lang.reflect.Method;
import java.util.List;

import javax.swing.JScrollPane;
import javax.swing.JTextField;

public class JMenubarAltTest extends javax.swing.JFrame {
    private static final long serialVersionUID = 1L;

    private KeyEventPostProcessor altPostprocessor;

    public JMenubarAltTest() {
        super();

        // Disable the ALT for the Mnemonic and put CTRL key instead:
        int[] ints = {java.awt.event.KeyEvent.CTRL_MASK};
        javax.swing.UIManager.put("Menu.shortcutKeys", ints);

        // Put the platform L&F, in my case I need this to work in Windows
        try {
            javax.swing.UIManager.setLookAndFeel(javax.swing.UIManager.getSystemLookAndFeelClassName());
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException
                | javax.swing.UnsupportedLookAndFeelException e1) {
            e1.printStackTrace();
        }

        this.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);

        // Create a random menu with some random items
        javax.swing.JMenuBar jmb = new javax.swing.JMenuBar();
        javax.swing.JMenu jm1 = new javax.swing.JMenu("menu1");
        jm1.setMnemonic(java.awt.event.KeyEvent.VK_M);
        jm1.add(new javax.swing.JMenuItem("item1"));
        jm1.add(new javax.swing.JMenuItem("item2"));
        jm1.add(new javax.swing.JMenuItem("item3"));

        javax.swing.JMenu jm2 = new javax.swing.JMenu("menu1");
        jm2.setMnemonic(java.awt.event.KeyEvent.VK_E);
        jm2.add(new javax.swing.JMenuItem("item1"));
        jm2.add(new javax.swing.JMenuItem("item2"));
        jm2.add(new javax.swing.JMenuItem("item3"));

        jmb.add(jm1);
        jmb.add(jm2);
        this.setJMenuBar(jmb);

        // Get a JTextArea to show what happens with the focus
        javax.swing.JTextArea jta = new javax.swing.JTextArea();

        // Disable ALT key presses when the textarea is focused
        jta.addFocusListener(new FocusListener() {

            @Override
            public void focusLost(FocusEvent e) {
                addAltPostprocessor();
            }

            @Override
            public void focusGained(FocusEvent e) {
                removeAltProcessor();
            }
        });

        this.getContentPane().add(new JScrollPane(jta));
        this.getContentPane().add(new JTextField(), BorderLayout.SOUTH);
        this.setSize(400, 300);
        this.setLocationRelativeTo(null);
        this.setVisible(true);
    }

    // use reflection to remove the Windows L&F ALT processor.
    private void removeAltProcessor() {
        if (altPostprocessor == null) {
            try {
                Method method = KeyboardFocusManager.class.getDeclaredMethod("getKeyEventPostProcessors");
                method.setAccessible(true);
                @SuppressWarnings("unchecked")
                List<KeyEventPostProcessor> list =
                        (List<KeyEventPostProcessor>) method.invoke(KeyboardFocusManager.getCurrentKeyboardFocusManager());
                for (KeyEventPostProcessor pp : list) {
                    if (pp.getClass().getName().contains("WindowsRootPaneUI")) {
                        KeyboardFocusManager.getCurrentKeyboardFocusManager().removeKeyEventPostProcessor(pp);
                        altPostprocessor = pp;
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        } else {
            KeyboardFocusManager.getCurrentKeyboardFocusManager().removeKeyEventPostProcessor(altPostprocessor);
        }
    }

    private void addAltPostprocessor() {
        if (altPostprocessor != null) {
            KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventPostProcessor(altPostprocessor);
        }
    }

    public static void main(java.lang.String[] args) {
        new JMenubarAltTest();
    }
}

在这个例子中，当文本的区域被聚焦ALT处理被禁用。 对于文本字段是中高音的处理仍处于启用状态。



文章来源: Disable single ALT type to activate the menu
标签： java swing shortcut jmenu windows-look-and-feel
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