JList not updating when set to new DefaultListModel

Question

public class MainMenu extends JFrame {
    private JPanel panel,file_list_panel;
    private JPanel contentPane;
    private JMenuBar menuBar;
    private JMenu mnNewMenu1,mnNewMenu2,mnNewMenu3;
    private JMenuItem mt1,mt2,mt3;
    private JPanel right,left ,bottom;
    private JSplitPane spver ,sphor;
    private JTabbedPane tabbedPane;
    private JLabel label;
    private JList<String> list_1;
    private JScrollPane jscroll_list;
    private DefaultListModel listmodel_1 = new DefaultListModel();


    public MainMenu() {




    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
    setBounds(0,0,screenSize.width, screenSize.height);
    setExtendedState(getExtendedState() | JFrame.MAXIMIZED_BOTH);
    int intValue = Integer.parseInt( "EEEEEE",16);
    Color aColor = new Color( intValue );
    UIManager.put("TabbedPane.background", new Color(230, 216, 174));
    UIManager.put("TabbedPane.selected", Color.WHITE); 
    UIManager.put("TabbedPane.contentAreaColor",aColor ); 
    UIManager.put("TabbedPane.focus", Color.WHITE); 

    setTitle("Main Menu");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    //setBounds(100, 100, 848, 680);
    //setLocation(10, 10);
    setLocationRelativeTo(null); // set jFrame alignment to center

    //parent(first) panel 
    contentPane = new JPanel();
    contentPane.setBackground(Color.BLACK);
    contentPane.setBorder(new EmptyBorder(2, 2, 2, 2));
    setContentPane(contentPane);
    contentPane.setLayout(new BorderLayout(0, 0));

    //Main Menu BAR
    menuBar = new JMenuBar();
    menuBar.setFont(new Font("Tekton Pro Ext", Font.PLAIN, 11));
    setJMenuBar(menuBar);

    //Menu 1
    mnNewMenu1 = new JMenu("New menu");
    menuBar.add(mnNewMenu1);
    //Menu 1 MenuItem 1

    mt1 = new JMenuItem("Browse New Project");
    mt1.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
        BrowseScreen frame = new BrowseScreen();
        frame.setVisible(true);
        }


    });


    mnNewMenu1.add(mt1);




    //second panel
    panel = new JPanel();
    contentPane.add(panel, BorderLayout.CENTER);
    panel.setLayout(new BorderLayout(0, 0));

    spver =new  JSplitPane(JSplitPane.VERTICAL_SPLIT);
    spver.setDividerLocation(500);
    spver.setEnabled(false);

    bottom=new JPanel();
    sphor =new  JSplitPane(JSplitPane.HORIZONTAL_SPLIT);
    sphor.setEnabled(false);
    spver.setTopComponent(sphor);
    spver.setBottomComponent(bottom);
    bottom.setLayout(null);
    panel.add(spver);

    sphor.setDividerLocation(180);
    left =new JPanel();
    right =new JPanel();
    sphor.setRightComponent(right);
    right.setLayout(new GridLayout(0, 1, 0, 0));

    tabbedPane = new JTabbedPane(JTabbedPane.TOP);
    tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);

    JPanel tab1 = new JPanel();
    tabbedPane.addTab("fffa", tab1);
    tabbedPane.setMnemonicAt(0, KeyEvent.VK_1);

    JPanel tab2 = new JPanel();
    tabbedPane.addTab("TAB1", tab2);
    tabbedPane.setMnemonicAt(0, KeyEvent.VK_1);



    right.add(tabbedPane);
    sphor.setLeftComponent(left);
    left.setLayout(new BorderLayout(0, 0));

    file_list_panel= new JPanel();
    file_list_panel.setBackground(Color.BLACK);
    file_list_panel.setForeground(Color.WHITE);

    label = new JLabel("Java Files of Project");
    label.setBackground(Color.BLACK);
    label.setForeground(Color.WHITE);
    label.setFont(new Font("Garamond", Font.BOLD, 14));
    file_list_panel.add(label);
    left.add(file_list_panel, BorderLayout.NORTH);


    list_1 = new JList<String>(listmodel_1);



    jscroll_list = new JScrollPane(list_1);
    left.add(jscroll_list, BorderLayout.CENTER);


    }
    public  void setList(Vector<String> files){
        listmodel_1.removeAllElements();
        list_1.removeAll();
        for(int i=0;i<files.size();i++)
            listmodel_1. addElement(files.elementAt(i));
        list_1.setModel(listmodel_1);
        this.invalidate();
        this.validate();
        this.repaint();
    }

}

setList is called from the browse window before it calls setVisible(false); ie . this methods gets called when the browse window disappears .. it does all the things in method but does not update it in the MainMenu public void setFileList(){ MainMenu mm= new MainMenu(); mm.setList(java_files); }

list_1 -JList listmodel_1=DefaultListModel

i've tried to refreshing the frame but does not refresh after adding the new list to the Main Window ...

before JList is updated im browsing the the files in another window then it is set to setVisible(false) then MainMenu gets focused and calls the setList method but its not changing

Answer 1

Basically, you are creating a new JList and associating your model with it, but this has no effect on the JList that is on the screen

public  void setList(Vector<String> files){
    // Good...
    listmodel_1.removeAllElements();
    // Not required, has nothing to do with the items in the list
    //list_1.removeAll();
    // Good
    for(int i=0;i<files.size();i++)
        listmodel_1. addElement(files.elementAt(i));
    // This here is your problem
    //list_1=new JList<String>(listmodel_1);
    // Because I have no idea what model list_1 is actually using...
    list_1.setModel(listmodel_1);
    //list_1.setSelectedIndex(0);
    //this.invalidate();
    //this.validate();
    //this.repaint();
}

Answer 2

You're creating a new JList<String> and copying the reference to your instance variable - but you're neither removing the old JList from the frame, nor adding the new one. Just changing the variable won't do that.

Rather than creating a new JList<String>, why don't you just replace the model of the existing one? Remove this line:

list_1=new JList<String>(listmodel_1);

and you may find it just works. (You're already setting the model in the subsequent line...)