CODEWITHSUNDEEP
javaswingjframejbuttonactionlistener
Martin Awano
Martin Awano

Reputation: 86

how do you change the color of a jbutton after it is clicked?

I am making a jFrame that represents a go board. I want a click of a given button to change the color to represent placing a piece on the board. In my code below, I show a method that should be able to change the color of a button (it only changes the background of the whole frame). First question: Why is the button color not changing (this is not my bigger problem about changing color after click occurs, my preliminary issue is that the button color will not change). I do not get any errors, the button color just never changes. 

public static void showBoard()
{
    JFrame frame2 = new JFrame("Go Board");
    frame2.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    for(int i = 19*19; i > 0; i--)
    {
      JButton firstButton = new JButton("");

      firstButton.setBackground(Color.blue);
      firstButton.setVisible(true);
      firstButton.setContentAreaFilled(true);
      firstButton.setOpaque(true);

      firstButton.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e)
        {
          javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() 
            {
              System.out.println("ddsd");
              //int[] arr = findMove(0);
            }
          });
        }
      });
      frame2.getContentPane().add(firstButton);
    }
    frame2.setComponentOrientation(ComponentOrientation.LEFT_TO_RIGHT);
    frame2.setLayout(new GridLayout(19,19));
    frame2.pack();
    frame2.setVisible(true);
}

My second problem, getting the button to change color after being clicked, is presumably affected by the fact that I am not able to even change the button color. To get the button to change color after a click, I plan to put the button color change code inside the action listener.

So in summation, how can I change the color of the button after a click?

ANSWER:

The problem was the look and feel of my mac. Look to the checked answer for how to fix this if you have similar problem on your mac.

Upvotes: 0

Views: 9974

Answers (1)

Chronio
Chronio

Reputation: 757

You don't need to call SwingUtilities.invokeLater inside your ActionListener, as the actionPerformed(ActionEvent) method will be invoked on the Event Thread already.

The following example demonstrates how to change a Button's background color when it's clicked on:

public class ChangeButtonColor implements Runnable {
    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel(new javax.swing.plaf.metal.MetalLookAndFeel());
        } catch (UnsupportedLookAndFeelException e) {
            System.err.println("Cannot set LookAndFeel");
        }
        SwingUtilities.invokeLater(new ChangeButtonColor());
    }

    @Override
    public void run() {
        JFrame frame = new JFrame();
        frame.setLayout(new FlowLayout());

        JButton button1 = new JButton("click me");
        JButton button2 = new JButton("click me too");
        ActionListener listener = new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                Object source = e.getSource();
                if (source instanceof Component) {
                    ((Component)source).setBackground(Color.RED);
                }
            }
        };
        button1.addActionListener(listener);
        button2.addActionListener(listener);

        frame.add(button1);
        frame.add(button2);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }
}

Please note that the ActionListener used here can be used for all buttons. There is no need to create a new instance of it for every button.

Upvotes: 3

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