JColorChooser

[thatguy]

I can't seem to get the circle to change color after the user picks a new color from the JColorChooser. any ideas?

 
package bouncer;
 
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
 
public class Bouncer extends JComponent {
 
    private static final int FRAME_WIDTH = 300;
    private static final int FRAME_HEIGHT = 300;
 
    private static Color circleColor = (Color.RED);
 
    public void paintComponent(Graphics g) {
        Graphics g2 = (Graphics) g;
 
        g2.setColor(circleColor);
        g2.fillOval(130, 120, 10, 10);
 
    }
 
    public static void main(String[] args) {
 
        JFrame frame = new JFrame("Bouncing Ball");
 
        frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
 
        JButton button = new JButton("Choose Color");
 
        class AddColor implements ActionListener {
            @Override
            public void actionPerformed(ActionEvent event) {
                circleColor = JColorChooser.showDialog(null, "pick your color", circleColor);
            }
        }
 
        ActionListener listener = new AddColor();
        button.addActionListener(listener);
 
        JPanel panel = new JPanel();
 
        panel.add(button);
 
        frame.add(new Bouncer());
        frame.add(panel, BorderLayout.SOUTH);
 
    }
}

[Norm]

After you do something that you want to cause the paintComponent() method to be called, call the repaint() method to tell the JVM to call paintComponent()

[thatguy]

Thank you for the help. but now i'm confused on why this works. I called repaint which calls the paintComponent method but repaint is in the paintComponent method? so how does that work?

    public void paintComponent(Graphics g) {
        Graphics g2 = (Graphics) g;
 
        g2.setColor(circleColor);
        g2.fillOval(130, 120, 10, 10);
        repaint();
    }

[Norm]

Calling the repaint() method in the paintComponent() method doesn't make sense. I think it could cause a tight loop. The repaint() method tells the JVM to call the painting methods.
Call the repaint() method at the time and place that you have changed what is going to be painted. That would be where you have set the new color to be used.

[thatguy]

I agree and that is what I did at first I put the repaint() right after the color change like this

 
 
        class AddColor implements ActionListener {
            @Override
            public void actionPerformed(ActionEvent event) {
                circleColor = JColorChooser.showDialog(null, "pick your color", circleColor);
                repaint();
            }
        }

but I got an error saying, "non-static method repaint() cannot be referenced from a static context"

[Norm]

You need to use a reference to the component class that contains the repaint() method to call it:
refToClassWithRepaint.repaint();

The AddColor class does not have a repaint() method.

[thatguy]

I really appreciate all your help, thank you.

but now when I choose a color it doesn't change the color of the circle.

 
        class AddColor implements ActionListener {
            @Override
            public void actionPerformed(ActionEvent event) {
                circleColor = JColorChooser.showDialog(null, "pick your color", circleColor);
                Bouncer b = new Bouncer();
                b.repaint();
            }
        }

--- Update ---

could this have something to do with it?

 public Bouncer() {
 
        class MouseClickListener implements MouseListener {
            @Override
            public void mouseClicked(MouseEvent e) {
                float r = (float) Math.random();
                float g = (float) Math.random();
                float b = (float) Math.random();
 
                circleColor = new Color(r, g, b);
                repaint();
            }
            @Override
            public void mousePressed(MouseEvent e) {}
            @Override
            public void mouseReleased(MouseEvent e) {}
            @Override
            public void mouseEntered(MouseEvent e) {}
            @Override
            public void mouseExited(MouseEvent e) {}   
        }
        this.addMouseListener(new MouseClickListener());
    }

[Norm]

The new object b that is created is not the one being shown. You need to get access to the component that is currently being shown.

[thatguy]

Thanks again for all your help.