我如何获得一个jbutton来更新jlabel？

Question

I'm new to Java. First project, learning through Google new.

I want to update the text of a jlabel when the jbutton is pressed. I want to do a lot more, but if I can't get it to do that, it's not going further.

It's giving me an error on the name of the jlabel like it doesn't exist, but the exact same thing works lower down in the jlabel code.

"lblCode" of lblCode.setText(time); under the ActionEvent of the button is where it errors, lblCode cannot be resolved.

JButton btnRefresh = new JButton("Refresh");
    btnRefresh.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            lblCode.setText(time);
        }
    });
    contentPane.add(btnRefresh, BorderLayout.EAST);

    JLabel lblCode = new JLabel("");
    lblCode.setHorizontalAlignment(SwingConstants.CENTER);
    contentPane.add(lblCode, BorderLayout.CENTER);
    lblCode.setText(time);

How can it exist one place, and not the other? I'm stuck.

Sorry if this question is too basic. I feel stupid for having to ask.

Answer 1

You access lblCode before it is defined - move the

btnRefresh.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent arg0) {
        lblCode.setText(time);
    }
});

part below the initialization of lblCode .