2

我试图让我JMenuBar模拟 Firefox 和 iTunes 的菜单栏的行为。行为:菜单栏最初是隐藏的。但是,当您按下 时Alt,会出现菜单栏(选中第一个项目),当您没有选择菜单项时,菜单栏会消失。JMenuBar我的想法是ChangeListener在其SelectionModel.

但是,附加的SSCCE的行为并不如预期。当框架加载时,JMenuBar是不可见的。当您按下Alt时,将出现菜单栏并选择第一个菜单(感谢WindowsLookAndFeel)。但是,随后的每一次Alt按下都会触发 no ChangeEvents。我想不通为什么...

有谁有光可以散光吗?

public class MenuBarTest extends javax.swing.JFrame {

    public MenuBarTest() {
        initComponents();
        jMenuBar1.setVisible(false);
        jMenuBar1.getSelectionModel().addChangeListener(new ChangeListener() {
            @Override
            public void stateChanged(ChangeEvent e) {
                System.out.println(e.toString());
                jMenuBar1.setVisible(jMenuBar1.isSelected());
                System.out.println(jMenuBar1.isSelected());
                System.out.println(jMenuBar1.getSelectionModel().isSelected());
            }
        });
    }

    private void initComponents() {

        jMenuBar1 = new javax.swing.JMenuBar();
        jMenu1 = new javax.swing.JMenu();
        jMenuItem1 = new javax.swing.JMenuItem();
        jMenu2 = new javax.swing.JMenu();
        jMenuItem2 = new javax.swing.JMenuItem();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jMenu1.setText("File");
        jMenuItem1.setText("jMenuItem1");
        jMenu1.add(jMenuItem1);
        jMenuBar1.add(jMenu1);
        jMenu2.setText("Edit");
        jMenuItem2.setText("jMenuItem2");
        jMenu2.add(jMenuItem2);
        jMenuBar1.add(jMenu2);
        setJMenuBar(jMenuBar1);
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGap(0, 400, Short.MAX_VALUE));
        layout.setVerticalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGap(0, 279, Short.MAX_VALUE));

        pack();
    }

    public static void main(String args[]) {
        try {
            UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | javax.swing.UnsupportedLookAndFeelException ex) {
            ex.printStackTrace();
        }
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new NewClass().setVisible(true);
            }
        });
    }
    private javax.swing.JMenu jMenu1;
    private javax.swing.JMenu jMenu2;
    private javax.swing.JMenuBar jMenuBar1;
    private javax.swing.JMenuItem jMenuItem1;
    private javax.swing.JMenuItem jMenuItem2;
}
4

2 回答 2

3

看起来菜单栏一旦被选中就永远不会取消选中。不确定这是否是一个错误。

直接收听 MenuSelectionManager 可能是一个更好的主意,因为您可以在此处收到有关任何地方菜单选择的所有更改的通知。需要一些逻辑来过滤掉那些与 menuBar 无关的内容,类似于:

ChangeListener listener = new ChangeListener() {
    @Override
    public void stateChanged(ChangeEvent e) {
        MenuElement[] elements = MenuSelectionManager.defaultManager().getSelectedPath();
        jMenuBar1.setVisible(elements.length > 0 && elements[0] == jMenuBar1);
    }
};
MenuSelectionManager.defaultManager().addChangeListener(listener);

更新

隐藏菜单栏的一个严重缺点是其 menuItems 的加速器停止工作。原因是只有正在显示的组件的 componentInputMaps 被要求处理它们。这是在 swing 包的内部完成的,即包私有类 KeyboardManager。无法挂接自定义管理器(可以实现它来处理未显示的菜单栏)。

不过,在链条的另一端,我们可以进行干预。基本上有两个选项,都是子类菜单栏:

  • (非常肮脏的把戏!)覆盖 isShowing 以始终返回 true。我已经看到这样做了,但不能真正推荐,因为可能会有我不知道的副作用
  • 一个有点脏的技巧:添加一个属性 hidden 并实现 getPreferredSize 以在隐藏时返回 0 高度。肮脏是它对 RootPaneLayout 尊重首选项高度的依赖......

修改后的 ChangeListener:

bar.setHidden(true);
ChangeListener listener = new ChangeListener() {
    @Override
    public void stateChanged(ChangeEvent e) {
        MenuElement[] elements = MenuSelectionManager.defaultManager().getSelectedPath();
        bar.setHidden(!(elements.length >0 && elements[0] == bar));
    }
};
MenuSelectionManager.defaultManager().addChangeListener(listener);

自定义菜单栏:

public static class JHideableMenuBar extends JMenuBar {

    private boolean hidden;

    public void setHidden(boolean hidden) {
        if (this.hidden == hidden) return;
        this.hidden = hidden;
        revalidate();
    }

    @Override
    public Dimension getPreferredSize() {
        Dimension pref = super.getPreferredSize();
        if (hidden) {
            pref.height = 0;
        }
        return pref;
    }

}
于 2013-08-07T07:44:08.410 回答
2

但是,每次按下 Alt 都不会触发 ChangeEvents。我想不通为什么...

  • ChangeListener 从 SelectionModel、Mouse 或 Key 事件中触发事件,这些事件是预期的

  • 您可以模拟来自 ChangeListener 的事件,例如重置菜单上的选择(将其放在将焦点移动到 JTextField 上)

  • 有可访问的另一个侦听器,可以触发自己的事件并正确

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.ButtonModel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.MenuEvent;
import javax.swing.event.MenuListener;

public class MenuBarTest extends javax.swing.JFrame {

    private javax.swing.JMenu jMenu1;
    private javax.swing.JMenu jMenu2;
    private javax.swing.JMenuBar jMenuBar1;
    private javax.swing.JMenuItem jMenuItem1;
    private javax.swing.JMenuItem jMenuItem2;
    private JTextField text = new JTextField("text", 10);

    public MenuBarTest() {
        jMenuBar1 = new javax.swing.JMenuBar();
        jMenu1 = new javax.swing.JMenu();
        jMenu1.addMenuListener(new MenuListener() {
            @Override
            public void menuSelected(MenuEvent e) {
                System.out.println("MenuListener - Selected: " + e.toString());
            }

            @Override
            public void menuDeselected(MenuEvent e) {
                System.out.println("MenuListener - Deselected: " + e.toString());
            }

            @Override
            public void menuCanceled(MenuEvent e) {
                System.out.println("MenuListener - Canceled: " + e.toString());
            }
        });
        jMenu1.getModel().addChangeListener(new ChangeListener() {
            @Override
            public void stateChanged(ChangeEvent e) {
                ButtonModel model = (ButtonModel) e.getSource();
                if (model.isArmed()) {
                    System.out.println("ButtonModel - Armed: " + e.toString());
                } else if (model.isEnabled()) {
                    System.out.println("ButtonModel - Enabled: " + e.toString());
                } else if (model.isPressed()) {
                    System.out.println("ButtonModel - Pressed: " + e.toString());
                } else if (model.isRollover()) {
                    System.out.println("ButtonModel - Rollover: " + e.toString());
                } else if (model.isSelected()) {
                    System.out.println("ButtonModel - Selected: " + e.toString());
                } else {
                    System.out.println("ButtonModel - !!!!!????: " + e.toString());
                }
            }
        });
        jMenuItem1 = new javax.swing.JMenuItem();
        jMenu2 = new javax.swing.JMenu();
        jMenuItem2 = new javax.swing.JMenuItem();
        jMenu1.setText("File");
        jMenuItem1.setText("jMenuItem1");
        jMenu1.add(jMenuItem1);
        jMenuBar1.add(jMenu1);
        jMenu2.setText("Edit");
        jMenuItem2.setText("jMenuItem2");
        jMenu2.add(jMenuItem2);
        jMenuBar1.add(jMenu2);
        jMenuBar1.setVisible(false);
        jMenuBar1.addPropertyChangeListener(new PropertyChangeListener() {
            @Override
            public void propertyChange(PropertyChangeEvent evt) {
                String strPropertyName = evt.getPropertyName();
                System.out.println("PropertyChangeListener - NewValue: " + evt.getNewValue());
                System.out.println("PropertyChangeListener - OldValue: " + evt.getOldValue());
                System.out.println("PropertyChangeListener - PropagationId: " + evt.getPropagationId());
                System.out.println("PropertyChangeListener - PropertyName: " + evt.getPropertyName());
                if ("MENU.MP_BARBACKGROUND".equals(strPropertyName)) {
                    System.out.println("PropertyChangeListener - MENU.MP_BARBACKGROUND: " + evt.getNewValue());
                }
            }
        });
        jMenuBar1.getSelectionModel().addChangeListener(new ChangeListener() {
            @Override
            public void stateChanged(ChangeEvent e) {
                System.out.println("ChangeListener - " + e.toString());
                jMenuBar1.setVisible(jMenuBar1.isSelected());
                System.out.println("ChangeListener - " + jMenuBar1.isSelected());
                System.out.println("ChangeListener - " + jMenuBar1.getSelectionModel().isSelected());
                java.awt.EventQueue.invokeLater(new Runnable() {
                    @Override
                    public void run() {
                        text.grabFocus();
                        text.requestFocusInWindow();
                        text.setText(text.getText());
                        text.selectAll();
                    }
                });
            }
        });
        setJMenuBar(jMenuBar1);
        add(text, BorderLayout.NORTH);
        add(new JTextField("text", 10), BorderLayout.SOUTH);
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setPreferredSize(new Dimension(400, 300));
        pack();
    }

    public static void main(String args[]) {
        try {
            UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | javax.swing.UnsupportedLookAndFeelException ex) {
            ex.printStackTrace();
        }
        java.awt.EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new MenuBarTest().setVisible(true);
            }
        });
    }
}
于 2013-08-07T06:20:30.633 回答