Java JTable and JToolBar resizing strangely

Question

I noticed very strange behavior of my program today. Basically I have JToolBar uder which is JScrollPane with JTable. Both inside JPanel inside JFrame. Every container using MigLayout.

Now, if I start app, this is its default look: enter image description here

But, if I move JToolBar and clip it back to its original position, now it looks like this: enter image description here

Suddenly there are no borders. I would preffer if there werent any at all at first place, but changing look of GUI is not good feature at all... Please if you know what is wrong, help :)

CODE:

public class Gui extends JFrame {

private static final long serialVersionUID = 1L;
private JPanel mainPnl = null;
private JToolBar toolbar = null;
private Session session = null;

public Gui(Session session) {
    try {
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    } catch (UnsupportedLookAndFeelException e) {
    } catch (ClassNotFoundException e) {
    } catch (InstantiationException e) {
    } catch (IllegalAccessException e) {
    }

    this.session = session;

    setTitle("PRO2-Contact Manager v_0.1");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setSize(800,420);
    setResizable(true);

    initMenu();
    initMainPnl();
    initToolbar();
    initTable();

    // KeyboardFocusManager manager =
    // KeyboardFocusManager.getCurrentKeyboardFocusManager();
    // manager.addKeyEventDispatcher(new MyDispatcher(aList));

    setLocationRelativeTo(null);
    setVisible(true);
}

private void initMenu() {
    JMenuBar menu = new JMenuBar();
    MenuListener ml = new MenuListener();

    JMenu file = new JMenu("File");
    file.setMnemonic(KeyEvent.VK_F);
    menu.add(file);

    JMenuItem exit = new JMenuItem("Exit");
    exit.setMnemonic(KeyEvent.VK_E);
    exit.addActionListener(ml);
    file.add(exit);

    JMenu help = new JMenu("Help");
    help.setMnemonic(KeyEvent.VK_H);
    menu.add(help);

    JMenuItem controls = new JMenuItem("Controls");
    controls.setMnemonic(KeyEvent.VK_C);
    controls.addActionListener(ml);
    help.add(controls);

    JMenuItem about = new JMenuItem("About");
    about.setMnemonic(KeyEvent.VK_A);
    about.addActionListener(ml);
    help.add(about);

    setJMenuBar(menu);
}

private void initMainPnl(){
    mainPnl = new JPanel(new MigLayout());

    add(mainPnl);
}

private void initToolbar() {
    toolbar = new JToolBar(JToolBar.HORIZONTAL);
    toolbar.add(new JButton());
    mainPnl.add(toolbar,"wrap");
}

private void initTable() {
    MyTable table = new MyTable(new MyTableModel(this));
    JScrollPane sp = new JScrollPane(table);
    sp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);

    mainPnl.add(sp,"w 100%, h 100%");
}}

How are you calling `new MenuListener()`? `MenuListener` is an interface. — Paul, Dec 18 '11 at 07:30
It would also be more helpful if you'd posted an example that demonstrated your problem with classes that come with the JDK, unless your 3rd party classes (miglayout, mytable) are the cause of the problem. Without the extra classes people can't run your code which limits their ability to help. A `main` method would have been nice too. — Paul, Dec 18 '11 at 07:34

score 0 · Accepted Answer · answered Dec 20 '11 at 14:12

Technically, a JToolBar can be added to a container with any layout constraint. Automatic re-adding a floating toolBar to the container is supported only if for a BorderLayout. Instead of adding to the mainPanel, add it to the contentPane:

private void initToolbar() {
    toolbar = new JToolBar(JToolBar.HORIZONTAL);
    toolbar.add(new JButton());
    add(toolbar, BorderLayout.NORTH);
}

BTW: your code doesn't compile outside of your context - MyPanel, MyTableModel, MenuListener are local classes not available anywhere else plus it's missing a main method. For better help sooner, consider to supply a SSCCE in future :-)

Java JTable and JToolBar resizing strangely

1 Answers1