I'm developing a Java Swing app for an award winning password protection system, and I need a large custom cursor [ 80 x 80 ], you might ask why so large, there is an online web demo you may look at to learn why it needs to be so large : http://gatecybertech.net
That large cursor is used on the login page in the above link. Of course you need to create a test password first before you can try the login process.
But anyway, in my Swing app, I hit a limit of 32 x 32 for the largest possible custom cursor, my code looks like the following :
Image cursorImage = toolkit.getImage("Cursor_Crosshair.PNG");
Tabular_Panel.setCursor(Toolkit.getDefaultToolkit().createCustomCursor(cursorImage,new Point(0,0),"custom cursor"));
The image size of Cursor_Crosshair.PNG is : 80 x 80
But what shows up in the screen is a shrinked version of it at : 32 x 32
So my question is : how can I bypass the size limit on customer cursor image, and make the cursor to show up at the size of 80 x 80 ?
I know the OS might be the reason for the limit, is there a way to overcome it ?
Here's my take on the glass pane painting approach. This is set up to behave pretty much like setting a custom cursor. The default "arrow" cursor is hidden while the custom cursor is shown, and the custom cursor is hidden when a component has some other cursor set, such as a text box.
Unfortunately, it ended up seeming to require quite a bit of Swing black magic, so I don't like it very much, but it does seem to work correctly. I've done a cursor like this before, but it was for something simpler, so I didn't run in to these issues.
Some of the problems I ran in to are:
The glass pane intercepts cursor changes (described e.g. on SO here). The only solution I've been able to find is to override Component.contains(int,int) to return false (described here, shown here), but why that works and doesn't seem to break anything else is mysterious.
Mouse exit events sometimes return a location inside the bounds of the component, so I don't think there's a reliable way to know when the mouse leaves the window except to use a timer.
package mcve;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.imageio.*;
import java.net.*;
import java.io.*;
public class LargeCursor {
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
JFrame frame = new JFrame();
JPanel glass = new CustomGlassPane();
glass.add(new CursorPanel(), BorderLayout.CENTER);
frame.setGlassPane(glass);
// This next call is necessary because JFrame.setGlassPane delegates to the root pane:
// - https://docs.oracle.com/javase/9/docs/api/javax/swing/RootPaneContainer.html#setGlassPane-java.awt.Component-
// - http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/javax/swing/JFrame.java#l738
// And JRootPane.setGlassPane may call setVisible(false):
// - https://docs.oracle.com/javase/9/docs/api/javax/swing/JRootPane.html#setGlassPane-java.awt.Component-
// - http://hg.openjdk.java.net/jdk8/jdk8/jdk/file/687fd7c7986d/src/share/classes/javax/swing/JRootPane.java#l663
glass.setVisible(true);
JPanel content = createTestPanel();
content.setCursor(BlankCursor.INSTANCE);
frame.setContentPane(content);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
});
}
static class CustomGlassPane extends JPanel {
CustomGlassPane() {
super(new BorderLayout());
super.setOpaque(false);
}
#Override
public boolean contains(int x, int y) {
return false;
}
}
static class CursorPanel extends JPanel {
final BufferedImage cursorImage;
Point mouseLocation;
CursorPanel() {
try {
cursorImage = createTransparentImage(
ImageIO.read(new URL("https://i.stack.imgur.com/9h2oI.png")));
} catch (IOException x) {
throw new UncheckedIOException(x);
}
setOpaque(false);
long mask = AWTEvent.MOUSE_EVENT_MASK | AWTEvent.MOUSE_MOTION_EVENT_MASK;
Toolkit.getDefaultToolkit().addAWTEventListener((AWTEvent e) -> {
switch (e.getID()) {
case MouseEvent.MOUSE_ENTERED:
case MouseEvent.MOUSE_EXITED:
case MouseEvent.MOUSE_MOVED:
case MouseEvent.MOUSE_DRAGGED:
capturePoint((MouseEvent) e);
break;
}
}, mask);
// This turned out to be necessary, because
// the 'mouse exit' events don't always have
// a Point location which is outside the pane.
Timer timer = new Timer(100, (ActionEvent e) -> {
if (mouseLocation != null) {
Point p = MouseInfo.getPointerInfo().getLocation();
SwingUtilities.convertPointFromScreen(p, this);
if (!contains(p)) {
setMouseLocation(null);
}
}
});
timer.setRepeats(true);
timer.start();
}
void capturePoint(MouseEvent e) {
Component comp = e.getComponent();
Point onThis = SwingUtilities.convertPoint(comp, e.getPoint(), this);
boolean drawCursor = contains(onThis);
if (drawCursor) {
Window window = SwingUtilities.windowForComponent(this);
if (window instanceof JFrame) {
Container content = ((JFrame) window).getContentPane();
Point onContent = SwingUtilities.convertPoint(comp, e.getPoint(), content);
Component deepest = SwingUtilities.getDeepestComponentAt(content, onContent.x, onContent.y);
if (deepest != null) {
if (deepest.getCursor() != BlankCursor.INSTANCE) {
drawCursor = false;
}
}
}
}
setMouseLocation(drawCursor ? onThis : null);
}
void setMouseLocation(Point mouseLocation) {
this.mouseLocation = mouseLocation;
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (mouseLocation != null) {
int x = mouseLocation.x - (cursorImage.getWidth() / 2);
int y = mouseLocation.y - (cursorImage.getHeight() / 2);
g.drawImage(cursorImage, x, y, this);
}
}
}
static final class BlankCursor {
static final Cursor INSTANCE =
Toolkit.getDefaultToolkit().createCustomCursor(
new BufferedImage(1, 1, BufferedImage.TYPE_INT_ARGB),
new Point(),
"BLANK");
}
static JPanel createTestPanel() {
JPanel panel = new JPanel(new GridLayout(3, 3));
panel.setBorder(BorderFactory.createEmptyBorder(100, 100, 100, 100));
for (int i = 0; i < 9; ++i) {
if ((i % 2) == 0) {
JTextField field = new JTextField("Text Field");
field.setHorizontalAlignment(JTextField.CENTER);
panel.add(field);
} else {
panel.add(new JButton("Button"));
}
}
return panel;
}
static BufferedImage createTransparentImage(BufferedImage img) {
BufferedImage copy =
GraphicsEnvironment.getLocalGraphicsEnvironment()
.getDefaultScreenDevice()
.getDefaultConfiguration()
.createCompatibleImage(img.getWidth(),
img.getHeight(),
Transparency.TRANSLUCENT);
for (int x = 0; x < img.getWidth(); ++x) {
for (int y = 0; y < img.getHeight(); ++y) {
int rgb = img.getRGB(x, y) & 0x00FFFFFF;
int bright = (((rgb >> 16) & 0xFF) + ((rgb >> 8) & 0xFF) + (rgb & 0xFF)) / 3;
int alpha = 255 - bright;
copy.setRGB(x, y, (alpha << 24) | rgb);
}
}
return copy;
}
}
OK, after some research and modification, I found the answer :
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;
import javax.swing.event.MouseInputAdapter;
public class Demo_Large_Custom_Cursor
{
static private MyGlassPane myGlassPane;
// Create the GUI and show it. For thread safety, this method should be invoked from the event-dispatching thread.
private static void createAndShowGUI()
{
//Create and set up the window.
JFrame frame=new JFrame("Demo_Large_Custom_Cursor");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Start creating and adding components.
JCheckBox changeButton=new JCheckBox("Custom Cursor \"visible\"");
changeButton.setSelected(false);
//Set up the content pane, where the "main GUI" lives.
Container contentPane=frame.getContentPane();
contentPane.setLayout(new FlowLayout());
contentPane.add(changeButton);
JButton Button_1=new JButton("<Html><Table Cellpadding=7><Tr><Td>A</Td><Td>B</Td></Tr><Tr><Td>C</Td><Td>D</Td></Tr></Table></Html>");
Button_1.setPreferredSize(new Dimension(80,80));
Button_1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { Out("Button 1"); } });
contentPane.add(Button_1);
JButton Button_2=new JButton("<Html><Table Cellpadding=7><Tr><Td>1</Td><Td>2</Td></Tr><Tr><Td>3</Td><Td>4</Td></Tr></Table></Html>");
Button_2.setPreferredSize(new Dimension(80,80));
Button_2.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { Out("Button 2"); } });
contentPane.add(Button_2);
//Set up the menu bar, which appears above the content pane.
JMenuBar menuBar=new JMenuBar();
JMenu menu=new JMenu("Menu");
menu.add(new JMenuItem("Do nothing"));
menuBar.add(menu);
frame.setJMenuBar(menuBar);
//Set up the glass pane, which appears over both menu bar
//and content pane and is an item listener on the change
//button.
myGlassPane=new MyGlassPane(changeButton,menuBar,frame.getContentPane());
changeButton.addItemListener(myGlassPane);
frame.setGlassPane(myGlassPane);
//Show the window.
frame.setLocationRelativeTo(null);
frame.pack();
frame.setVisible(true);
}
private static void out(String message) { System.out.print(message); }
private static void Out(String message) { System.out.println(message); }
public static void main(String[] args)
{
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
}
/**
We have to provide our own glass pane so that it can paint.
*/
class MyGlassPane extends JComponent implements ItemListener
{
Point point;
//React to change button clicks.
public void itemStateChanged(ItemEvent e)
{
setVisible(e.getStateChange()==ItemEvent.SELECTED);
}
protected void paintComponent(Graphics g)
{
try
{
if (point!=null)
{
// g.setColor(Color.red);
// g.fillOval(point.x-10,point.y-10,20,20);
BufferedImage image=ImageIO.read(new File("C:/Cursor_Crosshair.PNG"));
g.drawImage(image,point.x-39,point.y-39,null);
}
}
catch (Exception e) { }
}
public void setPoint(Point p)
{
point=p;
}
public MyGlassPane(AbstractButton aButton,JMenuBar menuBar,Container contentPane)
{
CBListener listener=new CBListener(aButton,menuBar,this,contentPane);
addMouseListener(listener);
addMouseMotionListener(listener);
}
}
/**
Listen for all events that our check box is likely to be interested in. Redispatch them to the check box.
*/
class CBListener extends MouseInputAdapter
{
Toolkit toolkit;
Component liveButton;
JMenuBar menuBar;
MyGlassPane glassPane;
Container contentPane;
public CBListener(Component liveButton,JMenuBar menuBar,MyGlassPane glassPane,Container contentPane)
{
toolkit=Toolkit.getDefaultToolkit();
this.liveButton=liveButton;
this.menuBar=menuBar;
this.glassPane=glassPane;
this.contentPane=contentPane;
}
public void mouseMoved(MouseEvent e)
{
// redispatchMouseEvent(e,false);
redispatchMouseEvent(e,true);
}
public void mouseDragged(MouseEvent e)
{
redispatchMouseEvent(e,false);
}
public void mouseClicked(MouseEvent e)
{
redispatchMouseEvent(e,false);
}
public void mouseEntered(MouseEvent e)
{
redispatchMouseEvent(e,false);
}
public void mouseExited(MouseEvent e)
{
redispatchMouseEvent(e,false);
}
public void mousePressed(MouseEvent e)
{
redispatchMouseEvent(e,false);
}
public void mouseReleased(MouseEvent e)
{
redispatchMouseEvent(e,true);
}
//A basic implementation of redispatching events.
private void redispatchMouseEvent(MouseEvent e,boolean repaint)
{
Point glassPanePoint=e.getPoint();
Container container=contentPane;
Point containerPoint=SwingUtilities.convertPoint(glassPane,glassPanePoint,contentPane);
if (containerPoint.y<0)
{ //we're not in the content pane
if (containerPoint.y+menuBar.getHeight()>=0)
{
//The mouse event is over the menu bar.
//Could handle specially.
}
else
{
//The mouse event is over non-system window
//decorations, such as the ones provided by
//the Java look and feel.
//Could handle specially.
}
}
else
{
//The mouse event is probably over the content pane.
//Find out exactly which component it's over.
Component component=SwingUtilities.getDeepestComponentAt(container,containerPoint.x,containerPoint.y);
// if ((component!=null) && (component.equals(liveButton)))
if ((component!=null))
{
//Forward events over the check box.
Point componentPoint=SwingUtilities.convertPoint(glassPane,glassPanePoint,component);
component.dispatchEvent(new MouseEvent(component,e.getID(),e.getWhen(),e.getModifiers(),componentPoint.x,componentPoint.y,e.getClickCount(),e.isPopupTrigger()));
}
}
//Update the glass pane if requested.
if (repaint)
{
glassPane.setPoint(glassPanePoint);
glassPane.repaint();
}
}
}
And the Cursor_Crosshair.PNG is like this :
I have this code sample in a separate jDialog (jDialog is in the same package as that of JFrame) which used to check (using a Thread) if the jCheckBox1 in the jFrame is whether visible or not. JDialog is set to visible by clicking a JLabel (Change Password) in JFrame. I have not set the visibility of the JFrame even to false even after I click on the Change Password JLabel.
The problem I encountered is that even if the JFrame is not visible i.e when I run the JDialog separately (without clicking on the Change Password JLabel) it prints the "Visible" and I'm more than sure that the jFrame is not visible and not running.
This is the code snippet (Thread) I have used to check the visibility of the JFrame's jCheckBox1:
LockOptions lock = new LockOptions();
private void setLocation2() {
new Thread() {
public void run() {
boolean running = true;
while (running) {
try {
Thread.sleep(1000);
if (lock.jCheckBox1.isVisible()) {
System.out.println("Visible");
} else {
System.out.println("Not Visible");
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}.start();
}
And this is the Code I have written in JFrame's Change Password JLabel:
private void jLabel9MouseClicked(java.awt.event.MouseEvent evt) {
Container c = new ChangePassword(this, rootPaneCheckingEnabled);
if (!c.isShowing()) {
c.setVisible(true);
hideMeToSystemTray();
this.requestFocusInWindow();
}
}
But when I run the JDialog separately (without clicking on the Change Password JLabel) it prints the "Visible"
I have attached a Screenshots of both JFrame and JDialog
JFrame containing jCheckBox1
JDialog:
OK, let's have the simplest possible example.
The following code creates a main frame having a button to create a new frame of class LockOptionsWindow, which extends JFrame.
The class FrameDemo implements Runnable. So can it be accessed on the event dispatching thread using SwingUtilities.invokeLater as mentioned in Swing's Threading Policy. So it is possible creating a new thread checklockoptionswindow which then can check whether the new window created by the button is visible or not visible.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class FrameDemo extends WindowAdapter implements ActionListener, Runnable {
private LockOptionsWindow lockoptionswindow;
private Thread checklockoptionswindow = new Thread();
private void showLockOptionsWindow() {
if (lockoptionswindow != null && lockoptionswindow.isDisplayable()) {
lockoptionswindow.setVisible(true);
lockoptionswindow.setExtendedState(Frame.NORMAL);
} else {
lockoptionswindow = new LockOptionsWindow();
lockoptionswindow.setSize(new Dimension(300, 100));
lockoptionswindow.setVisible(true);
lockoptionswindow.setExtendedState(Frame.NORMAL);
}
}
private void startCheckLockOptionsWindow() {
if (!checklockoptionswindow.isAlive()) {
checklockoptionswindow = new Thread() {
public void run() {
boolean running = true;
while (running) {
try {
Thread.sleep(1000);
if (lockoptionswindow.isVisible()) {
if (lockoptionswindow.getExtendedState() == Frame.ICONIFIED) {
System.out.println("Visible iconified");
} else {
System.out.print("Visible on screen ");
int x = lockoptionswindow.getLocation().x;
int y = lockoptionswindow.getLocation().y;
System.out.println("at position " + x + ", " + y);
}
} else {
System.out.println("Not Visible");
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
};
checklockoptionswindow.start();
}
}
public void actionPerformed(ActionEvent e) {
showLockOptionsWindow();
startCheckLockOptionsWindow();
}
public void run() {
JFrame frame = new JFrame("FrameDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton button = new JButton("Show LockOptions frame");
button.addActionListener(this);
Container contentPane = frame.getContentPane();
contentPane.add(button);
frame.setLocationRelativeTo(null);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new FrameDemo());
}
class LockOptionsWindow extends JFrame {
public LockOptionsWindow() {
super("LockOptions frame");
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
}
}
}
Edited to determine whether the LockOptionsWindow is visible iconified only or is really showed as window on the screen.
I have an application I'm making for a game to automatically update a game client.
Once you press Launch, it will open up my DownloadFrame (extends JDialog), and will look like this:
If you click the icon for the application in the taskbar, (maybe Windows 8 is the problem?) it will minimize the application like usual. However when you go to maximise the application again, the JDialog will be hidden, I'm assuming, behind the parent. It looks like this:
Here's my code for my extension of JDialog. Apologies in advance for it being messy.
public class DownloadFrame extends JDialog implements Runnable {
private static final long serialVersionUID = -8764984599528942303L;
private Background frame;
private ImageIcon[] gifs;
private JLabel spinner;
public DownloadFrame() {
super(Loader.application, false);
setLayout(null);
setUndecorated(true);
setAutoRequestFocus(true);
new Thread(this).start();
generateBackground();
generateButton();
generateGif();
}
private void generateBackground() {
frame = new Background("sub_background.png");
setSize(frame.getWidth(), frame.getHeight());
setBackground(new Color(1.0f, 1.0f, 1.0f, 0.0f));
setLocationRelativeTo(null);
setLocation(this.getX(), this.getY() + 5);
setLayout(null);
setContentPane(frame);
}
private void generateGif() {
gifs = Utils.generateGifImages();
spinner = new JLabel(gifs[0]);
spinner.setBounds(70, 30, gifs[0].getIconWidth(), gifs[0].getIconHeight());
add(spinner);
}
private HoverableButton cancel;
public HoverableButton getCancelButton() {
return cancel;
}
private void generateButton() {
cancel = new HoverableButton(Settings.CANCEL_BUTTON, 75, 145);
cancel.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
/*
* TODO -
* stop the download in progress
*/
for (HoverableButton button : Loader.application.getPrimaryButtons()) {
button.setActive(true);
button.setVisible(true);
}
dispose();
}
});
add(cancel);
}
private int cycleCount;
private void cycleGif() {
if (spinner == null) {
return;
}
cycleCount++;
if (cycleCount > 7) {
cycleCount = 0;
}
spinner.setIcon(gifs[cycleCount]);
}
#Override
public void run() {
while (true) {
cycleGif();
try {
Thread.sleep(100L);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
In case it's needed, here's my usage of it. Most of the stuff can be ignored I'm sure, it's simply there to hide the four buttons while the download is in progress.
((HoverableButton) components[2]).addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
HoverableButton source = (HoverableButton) components[2];
if (source.isActive()) {
try {
Thread.sleep(500L);
} catch (Exception ex) {
ex.printStackTrace();
}
if (panel == null) {
panel = new DownloadFrame();
panel.setVisible(true);
} else {
panel.setVisible(true);
panel.getCancelButton().removeHighlight();
}
for (HoverableButton button : getPrimaryButtons()) {
button.setActive(false);
button.setVisible(false);
button.removeHighlight();
}
/*
* TODO -
* handle checking for updates / downloading updates
*/
}
}
});
However when you go to maximise the application again, the JDialog will be hidden, I'm assuming, behind the parent
Yes. When you create the JDialog, you need to specify the "owner" JFrame of the dialog in the constructor.
So you must create and make the JFrame and make the frame visible before you create the dialog.
I've used java Spinner in Java Swing, but it had up and down arrows, is there a way to set it's orientation so that the arrows are left and right ?
Thanks to Jean-François Savard's answer, I'm one step closer, but still not quite right, I have the following lines :
public void installUI(JComponent c)
{
super.installUI(c);
c.removeAll();
FlowLayout FL=new FlowLayout();
FL.setHgap(0);
c.setLayout(FL);
JComponent editor=createEditor();
editor.setPreferredSize(new Dimension(30,16));
c.add(editor);
c.add(createPreviousButton());
c.add(createNextButton());
}
The spacing is not correct, how to fix it ? I hard coded in the above lines, how to automatically provide proper space for the text ?
A short search on google lead me to a custom implementation of JSpinner to do this.
public class LeftRightSpinnerDemo {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new LeftRightSpinnerDemo().makeUI();
}
});
}
public void makeUI() {
JSpinner spinner = new JSpinner();
spinner.setUI(new LeftRightSpinnerUI());
JFrame frame = new JFrame();
frame.add(spinner);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
class LeftRightSpinnerUI extends BasicSpinnerUI {
public static ComponentUI createUI(JComponent c) {
return new LeftRightSpinnerUI();
}
#Override
protected Component createNextButton() {
Component c = createArrowButton(SwingConstants.EAST);
c.setName("Spinner.nextButton");
installNextButtonListeners(c);
return c;
}
#Override
protected Component createPreviousButton() {
Component c = createArrowButton(SwingConstants.WEST);
c.setName("Spinner.previousButton");
installPreviousButtonListeners(c);
return c;
}
// copied from BasicSpinnerUI
private Component createArrowButton(int direction) {
JButton b = new BasicArrowButton(direction);
Border buttonBorder = UIManager.getBorder("Spinner.arrowButtonBorder");
if (buttonBorder instanceof UIResource) {
b.setBorder(new CompoundBorder(buttonBorder, null));
} else {
b.setBorder(buttonBorder);
}
b.setInheritsPopupMenu(true);
return b;
}
#Override
public void installUI(JComponent c) {
super.installUI(c);
c.removeAll();
c.setLayout(new BorderLayout());
c.add(createNextButton(), BorderLayout.EAST);
c.add(createPreviousButton(), BorderLayout.WEST);
c.add(createEditor(), BorderLayout.CENTER);
}
}
Make sure to add the correct imports as I removed them to lighten the code.
Refer to this for the original post.
There is a class AgentHome which extends JFrame.
AgentHome has a JPanel rem_panel. Checkboxes are added dynamically into rem_panel…number of checkboxes depending on the number of entries in the database table from where the text to be displayed by the textboxes are read.
AgentHome has an integer variable x and a checkbox arraylist rem_cbarr.
rem_cbarr stores the checkboxes as they are created and added to rem_panel.
I am trying to set the background color of these checkboxes to red when the variable x is set to 1 as the program executes.
I have implemented the TickerBehaviour of JADE framework to check if the variable x is set to 1.
I am unable to set the background color of the checkboxes to red. This is the code I have implemented. Please help. Thanks.
public void setup()
{
Behaviour loop = new TickerBehaviour( this, 2000 )
{
protected void onTick() {
timer();
}
};
addBehaviour( loop );
}
public void timer()
{
AgentHome hm=new AgentHome();
if(hm.x==1)
{
for (int i = hm.rem_cbarr.size()-1; i>=0; i--)
{
JCheckBox cb=hm.rem_cbarr.get(i);
cb.setBackground(Color.red);
hm.rem_panel.revalidate();
hm.rem_panel.repaint();
}
}
}
GUI operations need to be done on the EDT (Event Dispatcher Thread). In java this happens by calling SwingUtilities.invokeLater(Runnable run).
A number of things...
UI components should only ever be updated within the context of the Event Dispatching Thread
You should never perform any action which might block the Event Dispatching Thread (like using loops or Thread#Sleep to try and update the screen)
The Event Dispatching Thread is responsible for dispatching paint updates...
JCheckBox is transparent by default.
public class FlashCheckBox {
public static void main(String[] args) {
new FlashCheckBox();
}
public FlashCheckBox() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridBagLayout());
frame.add(new FlashyCheckBox());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class FlashyCheckBox extends JCheckBox {
private final Color defaultBackground;
private int flash;
private Timer flashTimer;
public FlashyCheckBox() {
defaultBackground = getBackground();
flashTimer = new Timer(500, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
flash++;
if (flash % 5 == 0) {
setOpaque(false);
setBackground(defaultBackground);
flashTimer.stop();
} else if (flash % 2 == 0) {
setBackground(Color.YELLOW);
setOpaque(true);
} else {
setBackground(defaultBackground);
setOpaque(false);
}
repaint();
}
});
flashTimer.setRepeats(true);
flashTimer.setCoalesce(true);
flashTimer.setInitialDelay(0);
addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
flashTimer.restart();
}
});
}
}
}