Using swing timer and ImageIcons

Question

Im trying to make a function that receive a image and imageicon as parameter, darken it for 2 secs and turn it back to normal, but i cant make the timer works as planned.

public void blinkImage(Image e, ImageIcon f) {
    ActionListener listener = new ActionListener(){
          public void actionPerformed(ActionEvent event){
              Graphics2D g2 = (Graphics2D) e.getGraphics();
              g2.setColor(new Color(0, 0, 0, 50));
              g2.fillRect(0, 0, f.getIconWidth(), f.getIconHeight());
          }
        };
        Timer displayTimer = new Timer(2000, listener);
        displayTimer.start();
        displayTimer.stop();
}

OBS: after this call will be a setIcon(f) in the main window, turning it back to normal. My question is: where should I put the start() and stop() calls? There is a better way to do it?

Thanks and sorry for bad english.

So should I just use start(), remove the stop() and remove the listener in the timer declaration? — user3111762, Nov 05 '15 at 17:56
Don't use getGraphics, this is not how custom painting is done — MadProgrammer, Nov 05 '15 at 20:29

score 3 · Answer 1 · answered Nov 05 '15 at 18:28

public void blinkImage(Image e, ImageIcon f)

Not sure why you have two parameters. Is the Image the Image in the Icon?

Painting onto the Image will be permanent. So if it is the same Image as the Icon you can't restore the Icon to its original state.

displayTimer.start();
displayTimer.stop();

You can't invoke stop() right after you start() the Timer because the Timer will never fire. So all you need is the start().

Since you only want the Timer to fire once you would just use:

timer.setRepeats( false );

then you don't have to worry about stopping the Timer.

One approach is create a custom Icon with two states. Then you can toggle the state of the Icon:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class DarkIcon implements Icon
{
    private Icon icon;
    private Color color;
    private boolean dark = false;

    public DarkIcon(Icon icon, Color color)
    {
        this.icon = icon;
        this.color = color;
    }

    public void setDark(boolean dark)
    {
        this.dark = dark;
    }

    @Override
    public int getIconWidth()
    {
        return icon.getIconWidth();
    }

    @Override
    public int getIconHeight()
    {
        return icon.getIconHeight();
    }

    @Override
    public void paintIcon(Component c, Graphics g, int x, int y)
    {
        icon.paintIcon(c, g, x, y);

        if (dark)
        {
            g.setColor(color);
            g.fillRect(x, y, getIconWidth(), getIconHeight());
        }
    }

    public static void main(String[] args)
    {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }

    public static void createAndShowGUI()
    {
        Icon icon = new ImageIcon("mong.jpg");
        DarkIcon darkIcon = new DarkIcon(icon, new Color(0, 0, 0, 128));
        JLabel label = new JLabel( darkIcon );

        Action blink = new AbstractAction()
        {
            @Override
            public void actionPerformed(ActionEvent e2)
            {
                darkIcon.setDark( false );
                label.repaint();
            }
        };

        Timer timer = new Timer(2000, blink);
        timer.setRepeats( false );

        JButton button = new JButton("Blink Icon");
        button.addActionListener( new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                darkIcon.setDark(true);
                label.repaint();
                timer.restart();
            }
        });

        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(label);
        f.add(button, BorderLayout.SOUTH);
        f.pack();
        f.setLocationRelativeTo( null );
        f.setVisible(true);
    }
}

Using swing timer and ImageIcons

1 Answers1