Thread: addActionListener to JButton

Hello,

I'm trying to write a method that makes a JButton and adds actionlistener but it doesn't work.
The code below is written in a Class that extends JPanel implements ActionListener.

I tried to replace "this" with instance of class but that also didn't work. Can somebody help me out, I wrote this to understand
how addActionListener works. But I can't figure it out

Thanks in advance!

	public void setButton(JButton knop, String naam)
	{
		knop = new JButton(naam);
		knop.setBackground(Color.LIGHT_GRAY);
		knop.setForeground(Color.BLACK);
		knop.setFont(new Font("Ariel", Font.PLAIN, 20));
		knop.addActionListener(this); <<<<<<-----
		this.add(knop);
	}

It doesnt give an error message, the ActionListener just doesn't work. When I click a button it does nothing..

Thank you for your response!

public class MainMenu extends JPanel implements ActionListener
{
	private JButton PLAY, HELP, CREDITS, EXIT, knop;
	private Image Background;
 
	public MainMenu()
	{
		setButton(PLAY, "Play");
		setButton(HELP, "Help");
		setButton(CREDITS, "Credits");
		setButton(EXIT, "Exit");
 
		Background = new ImageIcon("C:\\projectJava\\MenuBG.jpg").getImage();
	}
 
	public JButton setButton(JButton knop, String naam)
	{
		knop = new JButton(naam);
		knop.setBackground(Color.LIGHT_GRAY);
		knop.setForeground(Color.BLACK);
		knop.setFont(new Font("Ariel", Font.PLAIN, 20));
		knop.addActionListener(this);
		knop.setSize(350,350);
		knop.setAlignmentX(CENTER_ALIGNMENT);
		knop.setAlignmentY(CENTER_ALIGNMENT);
		this.add(Box.createRigidArea(new Dimension(0,20)));
		this.add(knop);
		return knop;
	}
 
	public void paintComponent(Graphics g)
	{
		super.paintComponents(g);
		g.drawImage(Background,0,0,null);
	}
 
	public void actionPerformed(ActionEvent e) 
	{
		if(e.getSource() == PLAY)
		{
			System.out.println("hello");
		}
		else if(e.getSource()==HELP)
		{
 
		}
		else if(e.getSource()==CREDITS)
		{
			System.out.println("werkt");
		}
		if(e.getSource()==knop)
		{
			System.out.println("Hello");
		}
	}
 
}

If I modify the constructor like this (with JButton knop) the ActionListener works and does print "Hello" like it is written in the actionPerformed method.
so from that I can see that the problem should be with that setButton method where I addActionListener(THIS), I think the problem is with that THIS.

Could it be? I'm not sure because I have no clue how to make it work otherwise

Thank you for your response

public MainMenu()
	{
                knop = new JButton("Help")
                knop.addActionListener(this);
                this.add(knop);
 
		setButton(PLAY, "Play");
		setButton(HELP, "Help");
		setButton(CREDITS, "Credits");
		setButton(EXIT, "Exit");
 
		Background = new ImageIcon("C:\\projectJava\\MenuBG.jpg").getImage();
	}

When I click a button, suppose PLAY, it should print out "hello". It doesn't do that, so I think the THIS in knop.addActionListener(THIS) is for the ActionListener and is supposed to be written in the constructor. Am I correct?

I don't think I understand the problem, but I also don't really understand what you're saying about a program that shows the problem. I'm kind of really new to Java.
Thank you for the help though!

The only other class I've made is a JFrame to show a GUI, except that I haven't written any other program.
I still don't understand why it doesn't recognize actionperformed for the Button but I found another way to fix it

I made another class ButtonListener implements ActionListener and an actionPerformed in that class which will handle the buttonclick.
In my MainMenu class, in setButton method I've written knop.addActionListener(new ButtonListener()).

And that works