1

在我之前的帖子之后，我写了一个监听器：

@Override
public void keyTyped(KeyEvent keyEvent) 
{
    PolygonFiller polyFiller = new PolygonFiller();
    char key = keyEvent.getKeyChar();

    final boolean runForever = true;

    switch(key)
    {
        /**
         *  Fill the polygons 
         */
        case FILL_POLYGON:      
        {
            if (greenLightForFilling == true)
            {

                while (runForever)
                {
                    fillPolygon(polyFiller);
                    KeyListener listener = new KeyListener()
                    {
                        public void keyPressed(KeyEvent keyEvent) 
                        {
                            char keyOther = keyEvent.getKeyChar();
                            if (keyOther == 'F' || keyOther == 'f')
                                // can't use break;
                                runForever = false;
                        }

                        @Override
                        public void keyReleased(KeyEvent arg0) {}

                        @Override
                        public void keyTyped(KeyEvent arg0) {}
                    };
                }
            }
            break;

        }  // end FILL_POLYGON


        case FILL_POLYGON_LOWERCASE:
        {
            if (greenLightForFilling == true)
            {
                fillPolygon(polyFiller);
            }
            break;              

        }

        /**
         *  save all polygons in a .scn file
         */
        case SAVE_POLYGONS :         
        {
            if (greenLightForFilling == true)
            {
                saveWorkspace();
            } 
            break;  
        }   // end SAVE_POLYGONS



        case SAVE_POLYGONS_LOWERCASE:
        {
            if (greenLightForFilling == true)
            {
                saveWorkspace();
            } 
            break;  
        }

        /**
         *  Delete everything & load all polygons from .scn file
         */
        case LOAD_POLYGONS:      
        {
            loadWorkspace();
            break;
        }   

        case LOAD_POLYGONS_LOWERCASE:
        {
            loadWorkspace();
            break;
        }

        default: break;  
    } // end switch


}

目标：

  1. 从循环中中断，当我得到一秒钟f或F（我已经得到一个f/F当我进入循环时）。

  2. 我需要将第二个听众附加到某事上吗？

但我不能将其更改runForever为 false ，因为它是写在外面的。

即使我将其更改为final，我也无法将其值更改false为 。

有什么办法吗？

注意：我已经有一个用于输入开关盒的按键监听器！

编辑：

// Hot-keys hit by the user - used for keyboard listening
private static final char FILL_POLYGON = 'F';
private static final char SAVE_POLYGONS = 'S';
private static final char LOAD_POLYGONS = 'L';
private static final char FILL_POLYGON_LOWERCASE = 'f';
private static final char SAVE_POLYGONS_LOWERCASE = 's';
private static final char LOAD_POLYGONS_LOWERCASE = 'l';


    @Override
    public void keyTyped(KeyEvent keyEvent) 
    {
        PolygonFiller polyFiller = new PolygonFiller();
        char key = keyEvent.getKeyChar();

        final Settable runForever = new Settable();

        switch(key)
        {
            /**
             *  Fill the polygons 
             */
            case FILL_POLYGON:      
            {
                if (greenLightForFilling == true)
                {

                        KeyListener listener = new KeyListener()
                        {
                            public void keyPressed(KeyEvent keyEvent) 
                            {
                                char keyOther = keyEvent.getKeyChar();
                                if (keyOther == 'F' || keyOther == 'f')
                                    runForever.set(false);
                            }

                            @Override
                            public void keyReleased(KeyEvent arg0) {}

                            @Override
                            public void keyTyped(KeyEvent arg0) {}
                        };

                        this.addKeyListener(listener);


                        while (runForever.get())
                        {
                            fillPolygon(polyFiller);
                        }
                }
                break;

            }  // end FILL_POLYGON

...
}
4

3 回答 3

4

最终变量不能更改，但如果它们表示可变对象，则可以更改该对象的内容。

例如，如果你创建一个Settable类，并使用它的实例而不是boolean，你可以这样做：

class Settable {
    private boolean flag;
    public boolean get() {return flag;}
    public boolean set(boolean val) { flag = val; }
}

现在，在你的代码中使用一个final实例；Settable使用set(...)而不是分配，而get()不是直接访问：

final Settable runForever = new Settable();
runForever.set(true);
...
while (runForever.get()) {
    ...
    if (keyOther == 'F' || keyOther == 'f') runForever.set(false);
    ...
}
于 2013-04-02T12:49:58.227 回答
3

  • 请您阅读@kleopatra 在您之前的帖子中的评论吗？忽略它不是一个好主意

  • 不是永远，不是错误的方向，使用 KeyBindings 和 Swing Action 而不是 KeyListener

  • @dasblinkenlight 接受的答案在 Swing、Swing 和 Java2D 中没有解决任何问题，使用 KeyBindings 和 Swing Action，

例如

import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;

public class FullScreen {

    private static final long serialVersionUID = 1L;
    private JButton button = new JButton("Close Meeee");
    private JPanel myPanel = new JPanel();
    private JFrame frame = new JFrame();

    public FullScreen() {
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        });
        myPanel = new JPanel() {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(400, 300);
            }
        };
        myPanel.setFocusable(true);
        myPanel.add(button);
        frame.add(myPanel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //frame.setUndecorated(true);
        frame.getRootPane().getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(
                KeyStroke.getKeyStroke("ENTER"), "clickENTER");
        frame.getRootPane().getActionMap().put("clickENTER", updateBol());
        frame.pack();
        frame.setVisible(true);
        updateCol().setEnabled(false);
        updateDol().setEnabled(false);
    }

    private Action updateBol() {
        return new AbstractAction("updateBol") {
            private static final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("updateCol is " + updateBol().isEnabled());
                System.out.println("updateBol is " + updateCol().isEnabled());
                System.out.println("updateDol is " + updateDol().isEnabled());
                updateCol().actionPerformed(e);
                updateDol().actionPerformed(e);
            }
        };
    }

    private Action updateCol() {
        return new AbstractAction("updateCol") {
            private static final long serialVersionUID = 1L;
            private Boolean _enabled = false;

            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("updateCol is " + updateCol().isEnabled());
                if (updateCol().isEnabled()) {
                } else {
                }
            }

            public void setEnabled(Boolean bol) {
                _enabled = bol;
            }

            @Override
            public boolean isEnabled() {
                return _enabled;
            }
        };
    }

    private Action updateDol() {
        return new AbstractAction("updateDol") {
            private static final long serialVersionUID = 1L;
            private Boolean _enabled = false;

            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("updateDol is " + updateDol().isEnabled());
                if (updateCol().isEnabled()) {
                } else {
                }
            }

            public void setEnabled(Boolean bol) {
                _enabled = bol;
            }

            @Override
            public boolean isEnabled() {
                return _enabled;
            }
        };
    }

    public static void main(String[] args) {
        Runnable doRun = new Runnable() {
            @Override
            public void run() {
                FullScreen fullScreen = new FullScreen();
            }
        };
        SwingUtilities.invokeLater(doRun);
    }
}
于 2013-04-02T14:08:36.580 回答
1

您可以制作大小为 1 的最终布尔数组来存储您的标志。即使数组是最终的，它的元素也不是，所以你可以从匿名类中修改数组的元素。

于 2013-04-02T12:51:25.433 回答