如何从JMenuItem访问JTextPane内容？

Question

I'm working on a text editor using Java (Swing). So far I have made the body. I'm having problem with this feature:

• New (JMenuItem) (empties the content of the JTextArea).

When the user clicks on the button, the JTextArea content should be replaced with an empty string. This is my code (I'm ommiting code that's not relevant to the problem, such as menu creation, menu items addition, only adding the classes.)

This is the TextArea class:

class MyTextArea extends JTextArea implements ActionListener {
    JTextArea myTextArea;
    public MyTextArea() {
        init();

    }

    public void init(){
        setLineWrap(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {

    }
}

(Empty, as you can see.)

This is the MenuBar class:

class MyMenuBar extends JMenuBar implements ActionListener {
    private JMenu mArchivo;
    private JMenuItem mNuevo;

    public MyMenuBar(){
        init();
        add(mArchivo);
    }

    private void init() {
        mArchivo = settingUpMenus("Archivo", "Archivo", 'A');
        mNuevo = settingUpMenuItems("Nuevo", "Nuevo", 'N');
        mArchivo.add(mNuevo);
    }

    private JMenu settingUpMenus(String mTitle, String mDescription,         
char mMnemonic) {
        JMenu mMenu;
        mMenu = new JMenu(mTitle);
        mMenu.setMnemonic(mMnemonic);

mMenu.getAccessibleContext().setAccessibleDescription(mDescription);
        mMenu.setActionCommand(mTitle);
        mMenu.addActionListener(this::actionPerformed);
        return mMenu;
    }

    private JMenuItem settingUpMenuItems(String mTitle, String 
mDescription, char mMnemonic) {
        JMenuItem mMenuItem;
        mMenuItem = new JMenuItem(mTitle);
        mMenuItem.setMnemonic(mMnemonic);



  mMenuItem.getAccessibleContext().
setAccessibleDescription(mDescription);
        mMenuItem.setActionCommand(mTitle);
        mMenuItem.addActionListener(this::actionPerformed);
        return mMenuItem;
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        switch(e.getActionCommand()) {
            case "Nuevo":
                onNew();
                break;
        }
    }

    private void onNew() {

    }
}

And this is the class constructor where I add the JTextArea and the JMenu with it's items and all.

public Editor() {
    JScrollPane myScrollPane = new JScrollPane(new MyTextArea(), 
    JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, 
    JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
    systemLook();
    setTitle("Text editor");
    setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    setSize(new Dimension(800, 700));
    setVisible(true);
    setJMenuBar(new MyMenuBar());
    add(myScrollPane);
}

However, I have tried many ways for my new button to get access to the current instance of JTextArea and to modify it, such as getting the parent classes with the ActionEvent object in the actionPerformed method inside the JMenu class. But none of the intents I have done can access to the JTextArea. Any ideas? Should I implement it another way?

Answer 1

Just pass it as a parameter in the constructor of the menu bar like

...
private JTextArea myTextArea;

public MyMenuBar(MyTextArea myTextArea){
    init();
    add(mArchivo);
    this.myTextArea = myTextArea;
}
...

and in the main would look like

MyTextArea myTextArea = new MyTextArea();
JScrollPane myScrollPane = new JScrollPane(myTextArea, 
        JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, 
        JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
systemLook();
setTitle("Text editor");
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
setSize(new Dimension(800, 700));
setVisible(true);
setJMenuBar(new MyMenuBar(myTextArea));