What is the right way to flash a lable?

[Yaroslav Chinskiy]

Hi,

I am new to SWING and looking for the best practices.

I need to write a gui where based on some events table cells start/stop flashing. In the attached code I get 70% CPU util if I add 1000 lables.

So what am i doing wrong?

  
/*
 * Created on Jul 27, 2004
 */
 
package com.yarik.test.swing;
 
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
 
public class SimpleFlasingLables {
 
class TickerListenerLable extends JLabel implements ActionListener {
 
private int id;
 
Color offColor = Color.GREEN;
boolean on = true;
 
Color onColor = Color.RED;
 
/**
 *  
 */
public TickerListenerLable(String name, int id) {
 
super(name);
this.id = id;
}
 
/*
 * (non-Javadoc)
 * 
 * @see java.awt.event.ActionListener#actionPerformed(java.awt.event.ActionEvent)
 */
public void actionPerformed(ActionEvent e) {
 
if (on) {
setForeground(onColor);
} else {
setForeground(offColor);
}
on = !on;
}
 
}
 
public static void main(String[] args) {
 
SimpleFlasingLables frame = new SimpleFlasingLables();
 
}
 
int count = 1000;
int delay = 500;
JButton flashAll = new JButton("FLASH ALL");
JButton flashEven = new JButton("FLASH EVEN");
JButton flashOdd = new JButton("FLASH ODD");
TickerListenerLable[] lables = new TickerListenerLable[count];
JButton stop = new JButton("STOP");
 
Timer timer;
 
SimpleFlasingLables() {
 
JFrame frame = new JFrame("Simple Frame Test.");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
 
JPanel btnPanel = new JPanel();
 
btnPanel.add(flashAll);
btnPanel.add(flashEven);
btnPanel.add(flashOdd);
btnPanel.add(stop);
 
frame.getContentPane().add(panel, BorderLayout.CENTER);
frame.getContentPane().add(btnPanel, BorderLayout.NORTH);
flashAll.addActionListener(new ActionListener() {
 
public void actionPerformed(ActionEvent e) {
 
for (int i = 0; i < lables.length; i++) {
if (timer == null) {
 
timer = new Timer(delay, lables[i]);
timer.start();
} else {
timer.addActionListener(lables[i]);
}
}
 
flashAll.setEnabled(false);
flashEven.setEnabled(false);
flashOdd.setEnabled(false);
 
}
 
});
 
flashEven.addActionListener(new ActionListener() {
 
public void actionPerformed(ActionEvent e) {
 
for (int i = 0; i < lables.length; i++) {
if (i % 2 != 1) {
if (timer == null) {
 
timer = new Timer(delay, lables[i]);
timer.start();
} else {
timer.addActionListener(lables[i]);
}
}
}
flashAll.setEnabled(false);
flashEven.setEnabled(false);
flashOdd.setEnabled(false);
}
});
 
flashOdd.addActionListener(new ActionListener() {
 
public void actionPerformed(ActionEvent e) {
 
for (int i = 0; i < lables.length; i++) {
if (i % 2 == 1) {
if (timer == null) {
 
timer = new Timer(delay, lables[i]);
timer.start();
} else {
timer.addActionListener(lables[i]);
}
}
}
flashAll.setEnabled(false);
flashEven.setEnabled(false);
flashOdd.setEnabled(false);
 
}
});
 
stop.addActionListener(new ActionListener() {
 
public void actionPerformed(ActionEvent e) {
 
if (timer == null) {
return;
}
for (int i = 0; i < lables.length; i++) {
 
timer.removeActionListener(lables[i]);
lables[i].setForeground(Color.BLACK);
}
 
flashAll.setEnabled(true);
flashEven.setEnabled(true);
flashOdd.setEnabled(true);
 
}
 
});
 
for (int i = 0; i < lables.length; i++) {
lables[i] = new TickerListenerLable("Lable " + i, i);
 
panel.add(lables[i]);
 
}
 
frame.pack();
frame.setVisible(true);
 
}
}

Thank you.
[ July 27, 2004: Message edited by: Yaroslav Chinskiy ]

[Craig Wood]

This is a little different way of looking at things. I wonder how this does for your cpu usage.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.Timer;
 
public class FlashingLabels
{
    public static void main(String[]args)
    {
        LabelPanel labelPanel = new LabelPanel();
        FlashAction action = labelPanel.action;
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(action.getUIPanel(), "North");
        f.getContentPane().add(new JScrollPane(labelPanel));
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}
 
class LabelPanel extends JPanel
{
    LabelStore[] labels;
    FlashAction action;
 
    public LabelPanel()
    {
        int size = 10;
        labels = new LabelStore[size];
        action = new FlashAction(this);
        setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.insets = new Insets(5,0,5,0);
        gbc.weightx = 1.0;
        gbc.weighty = 1.0;
        for(int j = 0; j < labels.length; j++)
        {
            labels[j] = new LabelStore("label " + (j + 1));
            labels[j].getLabel().addMouseListener(action);
            if(j % 2 == 0)
                gbc.gridwidth = gbc.RELATIVE;
            else
                gbc.gridwidth = gbc.REMAINDER;
            add(labels[j].getLabel(), gbc);
        }
        setBackground(Color.white);
    }
 
    public void flash()
    {
        for(int j = 0; j < labels.length; j++)
            labels[j].flash();
        repaint();
    }
 
    public void flashOdd()
    {
        boolean flashing;
        for(int j = 0; j < labels.length; j++)
        {
            if(j % 2 == 0)
                flashing = true;
            else
                flashing = false;
            labels[j].reset();
            labels[j].setIsFlashing(flashing);
        }
    }
 
    public void reset()
    {
        for(int j = 0; j < labels.length; j++)
            labels[j].reset();
    }
 
    public LabelStore[] getLabels()
    {
        return labels;
    }
}
 
class FlashAction extends MouseAdapter
{
    LabelPanel labelPanel;
    Timer timer;
 
    public FlashAction(LabelPanel lp)
    {
        labelPanel = lp;
        timer = new Timer(1000, new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                labelPanel.flash();
            }
        });
    }
 
    public void mousePressed(MouseEvent e)
    {
        JLabel label = (JLabel)e.getSource();
        LabelStore[] labels = labelPanel.getLabels();
        for(int j = 0; j < labels.length; j++)
            if(label == labels[j].getLabel())
                labels[j].toggleFlashing();
    }
 
    public JPanel getUIPanel()
    {
        final JCheckBox
            flash = new JCheckBox("flash"),
            odd = new JCheckBox("odd");
        ActionListener l = new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                JCheckBox check = (JCheckBox)e.getSource();
                if(check == flash)
                {
                    if(timer.isRunning())
                        timer.stop();
                    else
                        timer.start();
                }
                if(check == odd)
                {
                    if(odd.isSelected())
                        labelPanel.flashOdd();
                    else
                        labelPanel.reset();
                }
            }
        };
        flash.addActionListener(l);
        odd.addActionListener(l);
        JPanel panel = new JPanel();
        panel.add(flash);
        panel.add(odd);
        return panel;
    }
}
 
class LabelStore
{
    JLabel label;
    Color on, off;
    boolean isFlashing;
 
    public LabelStore(String text)
    {
        label = new JLabel(text, JLabel.CENTER);
        label.setOpaque(true);
        label.setPreferredSize(new Dimension(125,20));
        on = Color.red;
        off = Color.pink;
        isFlashing = false;
        label.setBackground(off);
    }
 
    public void flash()
    {
        Color color = label.getBackground();
        if(isFlashing)
        {
            if(color == on)
                color = off;
            else
                color = on;
        }
        label.setBackground(color);
    }
 
    public JLabel getLabel()
    {
        return label;
    }
 
    public void setIsFlashing(boolean flashing)
    {
        isFlashing = flashing;
    }
 
    public void toggleFlashing()
    {
        isFlashing = !isFlashing;
    }
 
    public void reset()
    {
        isFlashing = false;
        label.setBackground(off);
    }
}