Thread: Simple Actionlistener problem

Hi,

This is probably a stupid problem, but my gui skills have kind of faded in a year.

In the following test code I'm adding a button to a panel, which is added to a frame. The button works fine, but it won't change it's color when pressed. Thanks in advance for any help.

public class test extends JFrame{
 
	public static void main (String[]args) {
 
		test t = new test();
	}
 
	public test() {
		JButton knapp = new JButton("button");
		JPanel panel = new JPanel();
		knapp.addActionListener(new listener());
		panel.add(knapp);
		add(panel);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
	}
 
	private class listener implements ActionListener {
 
		public void actionPerformed(ActionEvent e) {
			JButton test = (JButton)e.getSource();
			test.setBackground(Color.BLACK);
			System.out.println("why hello thar");
		}
 
	}
 
}

This is not an ActionListener issue as much as it is a JButton issue.

It is all good and well to set the color of a JButton, but it will have no effect if the JButton is still transparent. You have to remember to use the JComponent.setOpaque(boolean isOpaque) method for the color to show. So, to fix this, simply before (or after) setting the color of your JButton, include the statement:

test.setOpaque(true);

and you should be good.