Action Listener 从未在本地使用过

Question

ActionListener 从未在本地使用，我知道我遗漏了一些东西，但我无法弄清楚。我不明白为什么它已经添加到 Actionlisteners 列表中时从未使用过

public class GUIinterface extends JFrame{

    JMenuBar MenuBar;
    JMenu file;
    JMenu help;
    JMenuItem load;
    JMenuItem save;
    JMenuItem about;
    JTextField commandLine;
    GraphicsPanel gp;

    public GUIinterface() {
        setTitle("Menu");
        setSize(640,480);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        gp = new GraphicsPanel();
        add(gp);

        MenuBar = new JMenuBar();
        file = new JMenu("File");
        help = new JMenu("Help");
        load = new JMenuItem("Load");
        save = new JMenuItem("Save");
        about = new JMenuItem("About");
        commandLine = new JTextField();

        file.add(load);
        file.add(save);
        help.add(about);

        MenuBar.add(file);
        MenuBar.add(help);

        add(MenuBar);
        add(commandLine, BorderLayout.PAGE_END);

        file.addMenuListener(new myMenuListener());
        load.addActionListener(new myActionListener());
        save.addActionListener(new myActionListener());
        about.addActionListener(new myActionListener());

        setJMenuBar(MenuBar);
        setVisible(true);

        commandLine.addActionListener(new myActionListener());
    }

    private class myActionListener implements ActionListener{
        private class MyActionListener implements ActionListener {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (e.getSource() == about) {
                    System.out.println("A");
                    gp.about();
                }
            }
        }            

        public void actionPerformed(ActionEvent e) {
            System.out.println(commandLine.getText());
            if (e.getSource() == commandLine) {
                if (commandLine.getText().contains("penup")) {
                    gp.penUp();
                    commandLine.setText("");
                } else if (commandLine.getText().contains("pendown")) {
                    gp.penDown();
                    commandLine.setText("");
                } else if (commandLine.getText().contains("turnleft")) {
                    gp.turnLeft();
                    commandLine.setText("");
                } else if (commandLine.getText().contains("turnright")) {
                    gp.turnRight();
                    commandLine.setText("");
                } else if (commandLine.getText().contains("forward")) {
                    gp.forward(50);
                    commandLine.setText("");
                } else if (commandLine.getText().contains("backward")) {
                    gp.forward(-50);
                    commandLine.setText("");
                } else if (commandLine.getText().contains("black")) {
                    gp.setPenColour(Color.black);
                    commandLine.setText("");
                } else if (commandLine.getText().contains("red")) {
                    gp.setPenColour(Color.red);
                    commandLine.setText("");
                } else if (commandLine.getText().contains("green")) {
                    gp.setPenColour(Color.green);
                    commandLine.setText("");
                }  
            }
        }
    }
    private class myMenuListener implements MenuListener{

        public void menuCanceled(MenuEvent arg0) {
            System.out.println("cancel");   
        }

        public void menuDeselected(MenuEvent arg0) {
            System.out.println("deselect"); 
        }

        public void menuSelected(MenuEvent arg0) {
            System.out.println("select");   
        }
    }
}

监听器应该在按下时调用 gp.about() 方法来创建一个简单的图形

Answer 1

您有两个 ActionListener，MyActionListener 和 myActionListener，而您只使用 myActionListener

尝试将两者合二为一，就会有这样的东西：

private class myActionListener implements ActionListener{


    public void actionPerformed(ActionEvent e) {
        System.out.println(commandLine.getText());
        if (e.getSource() == about) {
            System.out.println("A");
            gp.about();
        }
        else if (e.getSource() == commandLine)
        {
            if (commandLine.getText().contains("penup"))
            {
                gp.penUp();
                commandLine.setText("");
            }
            else if (commandLine.getText().contains("pendown"))
            {
                gp.penDown();
                commandLine.setText("");
            }
            else if (commandLine.getText().contains("turnleft"))
            {
                gp.turnLeft();
                commandLine.setText("");
            }
            else if (commandLine.getText().contains("turnright"))
            {
                gp.turnRight();
                commandLine.setText("");
            }
            else if (commandLine.getText().contains("forward"))
            {
                gp.forward(50);
                commandLine.setText("");
            }
            else if (commandLine.getText().contains("backward"))
            {
                gp.forward(-50);
                commandLine.setText("");
            }
            else if (commandLine.getText().contains("black"))
            {
                gp.setPenColour(Color.black);
                commandLine.setText("");
            }
            else if (commandLine.getText().contains("red"))
            {
                gp.setPenColour(Color.red);
                commandLine.setText("");
            } 
            else if (commandLine.getText().contains("green"))
            {
                gp.setPenColour(Color.green);
                commandLine.setText("");
            } 

        }
    }
}

编辑： 通过naming convenction在java中

类名应该是名词，大小写混合，每个内部单词的首字母大写。尽量保持你的类名简单和描述性。使用完整的单词，避免使用首字母缩写词和缩写词（除非缩写词比长格式更广泛地使用，例如 URL 或 HTML）。

所以我建议你使用MyActionListener instaead myActionListener