Creating JButtons in Java

Question

I'm fairly new to Java and I've been having some difficulties with Swing. I'm trying to create a very simple GUI program which should be create a set of buttons but my code doesn't work.

Here's my code;

myPanel = new JPanel();

JButton myButton = new JButton("create buttons");
myButton.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        int val = Integer.parseInt(textfield.getText());
        for(int i = 0; i < val; i++) {
            JButton button = new JButton("");
            button.setText(String.valueOf(i));
            myPanel.add(button);
        }
    }
});

But nothing happens when I click to "create buttons" button. Can anyone tell me what I'm missing?

Mike42 · Accepted Answer · 2010-09-27 11:31:40Z

2

You need to refresh panels that are already running with revalidate:

myPanel.revalidate()

answered Sep 27, 2010 at 11:31

Mike42

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3 Comments

Raveline Over a year ago

Not sure, but shouldn't he pack() too ?

walters Over a year ago

I suppose he called pack on the JFrame that he's adding the JPanel on.

user85421 Over a year ago

pack should be used to adjust the size of the component. If it is fixed size there is no need to call pack.

walters · Accepted Answer · 2010-09-27 11:35:21Z

0

You might have to invoke the validate method on the myPanel to get the contents of the GUI to update, after adding a button on the panel. Also consider the use of IDEs(Netbeans, Eclipse, IntelliJ Idea etc...), that's if it's necessary, for GUI building.

answered Sep 27, 2010 at 11:35

walters

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