Help adding JButton to a JPanel from another method!

[Brendon Randall]

Hi all,

I have a bit of a problem, I am trying to add some JButtons into a JPanel from a method call that is triggered by a buttons actionlistener, the problem i have got is when it comes to adding the button it does not show on the JPanel but if i get the component count of the JPanel it shows it as being there. I am using Netbeans 6.5 and using a FlowLayout for my JPanel, this is what i have

in my first JPanel that i have i add buttons to it when the JPanel is created and this works fine

  categoryPane = new javax.swing.JPanel();

categoryPane.setBorder(new javax.swing.border.SoftBevelBorder(javax.swing.border.BevelBorder.RAISED));

categoryPane.setName("categoryPane");
ProductRepository prodRepo = new ProductRepository();
        ArrayList<String> catName = prodRepo.getCategoryName(parentName);
        int i = 0;
        Font font = new Font("Button Font", Font.PLAIN, 24);
        while (i < catName.size()) {
            JButton button = new JButton(catName.get(i));
            button.setFont(font);
            button.setActionCommand(catName.get(i));
            button.addActionListener(new CatListener());
            button.setVisible(true);
            categoryPane.add(button);
            i++;
        }  

As you can see i created my own actionlistener for these buttons which i attach to the buttons and this is what it looks like

  class CatListener implements ActionListener {

    public void actionPerformed(ActionEvent e) {
        PosTeller pos = new PosTeller();
        pos.removeCatPane();
        ProductRepository prodRepo = new ProductRepository();
        ArrayList<String> prod = prodRepo.getProdFromCat(e.getActionCommand(), PosTeller.parentName);
        pos.addToCatPane(prod);
    }  

In my actionlistener i then call a few methods that are in the PosTeller class as this is where my JPanel sits, here are the methods

  public void removeCatPane() {
        categoryPane.removeAll();
    }

    public void addToCatPane(ArrayList<String> cat) {
        productsPane.removeAll();
        Font font = new Font("Button font", Font.PLAIN, 24);
        int i = 0;
        while (i < cat.size()) {
            JButton button = new JButton(cat.get(i));
            button.setFont(font);
            button.setActionCommand(cat.get(i));
            button.addActionListener(new ProdListener());
            button.setVisible(true);
            productsPane.add(button);
            i++;
        }
    }  

The problem is when it gets to the addToCatPane() and i create the buttons to add to the productsPane absolutly nothing happens, nothing gets displayed!! but the component count shows that there are components there, i have called rePaint() reValidate() inValidate() etc etc and nothing seems to make them display....

Please can someone help me

[Michael Dunn]

normally when adding or removing components from a visible swing container you need both
container.revalidate();
container.repaint();

not always, but most times, both are required

[Brendon Randall]

Thanks for the reply, i have just tried that, this is what i did

  public void addToCatPane(ArrayList<String> cat) {
        productsPane.removeAll();
        Font font = new Font("Button font", Font.PLAIN, 24);
        int i = 0;
        while (i < cat.size()) {
            JButton button = new JButton(cat.get(i));
            button.setFont(font);
            button.setActionCommand(cat.get(i));
            button.addActionListener(new ProdListener());
            button.setVisible(true);
            productsPane.add(button);
            i++;
        }
        productsPane.revalidate();
        productsPane.repaint();
    }  

But still no luck the buttons do not show

[Michael Dunn]

you would need to post a compilable program, otherwise it's just a guessing game.

if productsPane's layoutmanger is null, your problem is there
if cat.size() < 1 your problem is there
etc

in posting a compilable program, get rid of the unnecessary stuff.
you're trying to get a JButton to appear, so the button's font, actionCommand,
actionListener etc are not part of the problem