We Keep Coding

Can't get absolute JLabel location

My JFrame uses a BorderLayout and it has a JLabel nested in several panels with different layout managers. I've tried several methods, however, cannot get the true position of where it sits in the frame.
I made a test UI and it seems like when other components are added the getX and getY parameters do not update. Other methods like getLocation do not provide a correct result either. Is there any way to obtain the exact location without manually calculating every possible offset from each component.
I am tracking the stated positions of the label (content) using a similar sized panel called content2 in the glass pane which I want to sit underneath content perfectly.
public class test {
private Dimension pSize = new Dimension(100,100);
private JFrame frame = new JFrame();
public static void main(String[] args) {
new test();
}
public test() {
//setup frame basics
frame.setPreferredSize(new Dimension(500,500));
frame.setLayout(new BorderLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// setup GUI
JMenuBar j = new JMenuBar();
JMenuItem a = new JMenuItem("lol");
j.add(a);
JPanel j2 = new JPanel();
//setup main panel
JPanel main = new JPanel();
main.setBackground(Color.DARK_GRAY);
//setup side panel
FlowLayout f1 = new FlowLayout(FlowLayout.LEADING);
f1.setHgap(10);
f1.setVgap(0);
JPanel side = new JPanel();
side.setLayout(new BorderLayout());
side.setBackground(Color.gray);
side.setPreferredSize(new Dimension(150,100));
//setup JLabel (the main focus)
JLabel content = new JLabel("a");
content.setOpaque(true);
content.setBackground(Color.blue);
content.setPreferredSize(pSize);
// Setup the internal panels of side
JPanel top = new JPanel();//The panel where CONTENT is, the main focus
JPanel bot = new JPanel();
top.setBackground(Color.WHITE);
bot.setBackground(Color.orange);
top.setLayout(f1);
top.add(content);
side.add(top, BorderLayout.NORTH);
side.add(bot, BorderLayout.CENTER);
frame.add(main, BorderLayout.CENTER);
frame.add(side, BorderLayout.WEST);
frame.add(j2, BorderLayout.NORTH);
frame.setJMenuBar(j);
frame.pack();
frame.setVisible(true);
//Setting up the glass panel
JPanel pane = new JPanel();
pane.setLayout(null);
pane.setOpaque(false);
JPanel content2 = new JPanel();
content2.setBackground(Color.red);
content.revalidate();
int x = content.getX();
int y = content.getY();
// y = (int) content.getLocation().getY(); //returns a completely wrong location
//y = (int) content.getLocationOnScreen(); //returns a completely wrong location
/*
Point p = new Point();
p.setLocation(x, y);
p = SwingUtilities.convertPoint(content2, x, y, frame);
//SwingUtilities.convertPoint(content, p, frame);
y = (int) p.getY();
*
* Tried multiple SwingUtility converions to no avail
*
*/
// y = y +j.getHeight() + j2.getHeight(); // Manually calculating the Y off set works successfully but is too tedious for large project
y = y + content.getHeight();
content2.setBounds(x,y,100,100);
pane.add(content2);
frame.setGlassPane(pane);
frame.getGlassPane().setVisible(true);
frame.pack();
}
}
//frame.getContentPane().add(content);
//frame.add(content);
frame.setPreferredSize(new Dimension(500,500));
content.setBorder(BorderFactory.createEmptyBorder());
side.setLayout(new BorderLayout());
JPanel top = new JPanel();
JPanel bot = new JPanel();
top.setBackground(Color.WHITE);
bot.setBackground(Color.orange);
side.add(top, BorderLayout.NORTH);
top.setLayout(f1);
top.add(content);
side.add(bot, BorderLayout.CENTER);
frame.add(main, BorderLayout.CENTER);
frame.add(j2, BorderLayout.NORTH);
frame.add(side, BorderLayout.WEST);
frame.pack();
frame.setVisible(true);
JPanel pane = new JPanel();
pane.setLayout(null);
pane.setOpaque(false);
JPanel content2 = new JPanel();
content2.setBackground(Color.red);
content.revalidate();
int x = content.getX();
int y = content.getY();
// y = y +j.getHeight() + j2.getHeight();
y = y + content.getHeight();
content2.setBounds(x,y,100,100);
pane.add(content2);
frame.setGlassPane(pane);
frame.getGlassPane().setVisible(true);
frame.pack();
}
}

Conceptually you could make use of SwingUtilities.convertPoint or SwingUtilities.convertRectangle to convert between container contexts, for example...
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.border.EmptyBorder;
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
GlassPane glassPane = new GlassPane();
JFrame frame = new JFrame();
frame.setGlassPane(glassPane);
frame.add(new MainPane(glassPane));
glassPane.setVisible(true);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public interface Tracker {
public void addTrackable(Trackable trackable);
public void removeTrackable(Trackable trackable);
}
public interface Trackable {
public JComponent[] getTrackedComponents();
}
public class MainPane extends JPanel {
private JLabel label = new JLabel("Catch me if you can");
public MainPane(Tracker tracker) {
setLayout(new GridBagLayout());
setBorder(new EmptyBorder(32, 32, 32, 32));
add(label);
tracker.addTrackable(new Trackable() {
#Override
public JComponent[] getTrackedComponents() {
return new JComponent[] { label };
}
});
}
}
public class GlassPane extends JPanel implements Tracker {
private List<Trackable> trackables = new ArrayList<>(8);
public GlassPane() {
setOpaque(false);
}
#Override
public void addTrackable(Trackable trackable) {
trackables.add(trackable);
revalidate();
repaint();
}
#Override
public void removeTrackable(Trackable trackable) {
trackables.remove(trackable);
revalidate();
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(Color.RED);
for (Trackable trackable : trackables) {
for (JComponent component : trackable.getTrackedComponents()) {
Rectangle relativeBounds = SwingUtilities.convertRectangle(component.getParent(), component.getBounds(), this);
g2d.draw(relativeBounds);
}
}
g2d.dispose();
}
}
}
Well, that's pretty boring, it's one component inside one container, let's trying something a little more complicated...
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
GlassPane glassPane = new GlassPane();
JFrame frame = new JFrame();
frame.setLayout(new GridLayout(2, 2, 8, 8));
frame.add(new MainPane(glassPane));
frame.add(new MainPane(glassPane));
frame.add(new MainPane(glassPane));
frame.add(new MainPane(glassPane));
frame.setGlassPane(glassPane);
glassPane.setVisible(true);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public interface Tracker {
public void addTrackable(Trackable trackable);
public void removeTrackable(Trackable trackable);
}
public interface Trackable {
public JComponent[] getTrackedComponents();
}
public class MainPane extends JPanel {
private JLabel label = new JLabel("Catch me if you can");
public MainPane(Tracker tracker) {
setLayout(new GridBagLayout());
setBorder(new CompoundBorder(new LineBorder(Color.DARK_GRAY, 1, true), new EmptyBorder(32, 32, 32, 32)));
add(label);
tracker.addTrackable(new Trackable() {
#Override
public JComponent[] getTrackedComponents() {
return new JComponent[]{label};
}
});
}
}
public class GlassPane extends JPanel implements Tracker {
private List<Trackable> trackables = new ArrayList<>(8);
private List<Color> masterColors = new ArrayList<>(Arrays.asList(new Color[]{
Color.RED,
Color.GREEN,
Color.BLUE,
Color.CYAN,
Color.DARK_GRAY,
Color.GRAY,
Color.MAGENTA,
Color.ORANGE,
Color.PINK,
Color.YELLOW,}));
public GlassPane() {
setOpaque(false);
}
#Override
public void addTrackable(Trackable trackable) {
trackables.add(trackable);
revalidate();
repaint();
}
#Override
public void removeTrackable(Trackable trackable) {
trackables.remove(trackable);
revalidate();
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(Color.RED);
List<Color> colors = new ArrayList<>(masterColors);
for (Trackable trackable : trackables) {
for (JComponent component : trackable.getTrackedComponents()) {
if (colors.isEmpty()) {
colors = new ArrayList<>(masterColors);
}
g2d.setColor(colors.remove(0));
Rectangle relativeBounds = SwingUtilities.convertRectangle(component.getParent(), component.getBounds(), this);
g2d.draw(relativeBounds);
}
}
g2d.dispose();
}
}
}
Here is a new smipler example program, trying to keep as close to your code as possible, that uses the convertRectangle but I can't manage to run it correctly
int y = (int) (r.getY() + r.getHeight()); ... are you deliberately trying to offset the "overlay"? This seems weird to me.
Another issue is, how does the GlassPane know when the child has changed position/size
So, I modified your code, getting rid of the "modification" to the x/y position (so I'm 100% sure that the conversion between context spaces is correct) and added a ComponentListener to monitor changes to the "target" component
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Rectangle;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import java.awt.*;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
public class Main {
private Dimension pSize = new Dimension(100, 100);
private JFrame frame = new JFrame();
private JLabel content = new JLabel("Grief");
private JPanel content2 = new JPanel();
private SidePane sidePane = new SidePane();
private GlassPane glass = new GlassPane();
private Menu menu = new Menu();
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
content.setBackground(Color.green);
content.setPreferredSize(pSize);
content.setOpaque(true);
//setup frame basics
frame.setPreferredSize(new Dimension(500, 500));
frame.setLayout(new BorderLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setGlassPane(glass);
frame.add(new MainPane());
// glass.setNewLocation();
// glass.revalidate();
frame.getGlassPane().setVisible(true);
// glass.setNewLocation();
frame.pack();
frame.setVisible(true);
}
});
}
public class MainPane extends JPanel {
public MainPane() {
//this.setBackground(Color.orange);
this.setLayout(new BorderLayout());
this.add(sidePane, BorderLayout.WEST);
this.add(menu, BorderLayout.NORTH);
}
}
public class SidePane extends JPanel {
public SidePane() {
FlowLayout f1 = new FlowLayout(FlowLayout.LEADING);
this.setLayout(f1);
this.setBackground(Color.blue);
this.add(content);
}
}
public class Menu extends JPanel {
public Menu() {
this.setBackground(Color.orange);
}
}
public class GlassPane extends JPanel {
private Rectangle target;
public GlassPane() {
this.setOpaque(false);
setLayout(null);
content2.setBackground(Color.BLACK);
content2.setPreferredSize(pSize);
content2.setOpaque(true);
add(content2);
content.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent e) {
updateOverlay();
}
#Override
public void componentMoved(ComponentEvent e) {
updateOverlay();
}
});
}
protected void updateOverlay() {
// Rectangle t = new Rectangle();
// t.setBounds((int) content.getLocation().getX(), (int) content.getLocation().getY(), content.getWidth(), content.getHeight());
// Rectangle r = SwingUtilities.convertRectangle(content.getParent(), content.getBounds(), this);
// Rectangle r = SwingUtilities.convertRectangle(content.getParent(), content.getBounds(), this);
target = SwingUtilities.convertRectangle(content.getParent(), content.getBounds(), this);
content2.setBounds(target);
// r = SwingUtilities.convertRectangle(content.getParent(), t, this);
// int x = (int) r.getBounds().getX();
// x = (int) r.getX();
// int y = (int) (r.getY() + r.getHeight());
//
// content2.setBounds(x, y, 100, 100);
// this.add(content2);
}
#Override
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2d = (Graphics2D) g.create();
if (target != null) {
g2d.setColor(Color.RED);
g2d.draw(target);
}
g2d.dispose();
}
}
}

If you have the coordinate within the component, transfer it to screen coordinates using your component's convertPointToScreen(). Afterwards you can transfer back to see where in the window it sits by using the frame's convertPointFromScreen().
Or eliminate one of the two steps by directly using convertPoint().

Fixed the positioning issue using #MadProgrammer 's method of SwingUtilities.convertRectangle and called a new method at the end of the constructor which positioned the tracker panel.
Created a separate class for the glass pane
private class GlassPane extends JPanel {
public GlassPane() {
this.setLayout(null);
}
public void setNewLocation() {
Rectangle r = SwingUtilities.convertRectangle(top, content.getBounds(), this);
JPanel content2 = new JPanel();
int x = (int) r.getBounds().getX();
x = (int) r.getX();
int y = (int) (r.getY() + r.getHeight() + 1);
content2.setBounds(x, y, 100,100);
this.add(content2);
}
}
And added a call to the new method setNewLocation() at the end of the constructor
public test() {
**...**
frame.pack();
frame.setVisible(true);
glass.setNewLocation();
}

Set JButton background color on windows

I have a JButton which I want to set the background to a color.
JButton button = new JButton();
button.setVisible(true);
button.setPreferredSize(new Dimension(student_scroll.getWidth(), 50));
button.setBorder(BorderFactory.createLineBorder(Color.WHITE, 1));
button.setBackground(Color.BLACK);
button.setForeground(Color.WHITE);
button.setOpaque(true);
I used this for mac and it showed up as I wanted it to be. However, upon trying it on windows, the foreground is white(as it should) but the background is empty.
Setting background color to JButton
says to add button.setContentAreaFilled(false); which I did but had no effect. Most others say to add button.setOpaque(true);which I also did already.
What else do I have to do so that it will show up with a black background?
EDIT
As requested, the SSCCE:
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class MainSwing extends JFrame {
private static final long serialVersionUID = -8231889836024827530L;
public static void main(String[] args) {
try {
System.setProperty("apple.laf.useScreenMenuBar", "true");
System.setProperty("com.apple.mrj.application.apple.menu.about.name", "Test");
UIManager.put("ScrollBarUI", "main.CustomScrollBarUI");
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
}
catch(ClassNotFoundException e) {
System.out.println("ClassNotFoundException: " + e.getMessage());
}
catch(InstantiationException e) {
System.out.println("InstantiationException: " + e.getMessage());
}
catch(IllegalAccessException e) {
System.out.println("IllegalAccessException: " + e.getMessage());
}
catch(UnsupportedLookAndFeelException e) {
System.out.println("UnsupportedLookAndFeelException: " + e.getMessage());
}
SwingUtilities.invokeLater( new Runnable() {
public void run() {
JFrame frame = new JFrame() {
Container c = getContentPane();
JButton button = new JButton("Hello");
{
button.setText("Hello");
button.setVisible(true);
button.setPreferredSize(new Dimension(100, 50));
button.setBorder(BorderFactory.createLineBorder(Color.WHITE, 1));
button.setBackground(Color.BLACK);
button.setForeground(Color.WHITE);
button.setOpaque(true);
c.add(button);
}
};
frame.setSize(500, 500);
frame.setBackground(Color.BLACK);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
}
It seems that the problem has something to do with the line: UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); as when I remove it, the buttons are black.

I'm guessing from those UIManager key/value pairs that the PLAF is the OS X based Aqua PLAF. And that seems to be part of the problem here. Here it is without the content area filled on Windows.
import java.awt.*;
import javax.swing.*;
public class MainSwing extends JFrame {
public static void main(String[] args) {
try {
System.setProperty("apple.laf.useScreenMenuBar", "true");
System.setProperty("com.apple.mrj.application.apple.menu.about.name", "Test");
UIManager.put("ScrollBarUI", "main.CustomScrollBarUI");
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
e.printStackTrace(); // more info for less LOC!
}
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame = new JFrame() {
Container c = getContentPane();
JButton button = new JButton("Hello");
{
c.setLayout(new GridLayout(0,1));
c.add(new JButton("Hi"));
button.setText(UIManager.getSystemLookAndFeelClassName());
button.setVisible(true);
button.setPreferredSize(new Dimension(400, 100));
button.setBorder(BorderFactory.createLineBorder(Color.WHITE, 1));
button.setContentAreaFilled(false);
button.setBackground(Color.BLACK);
button.setForeground(Color.WHITE);
button.setOpaque(true);
c.add(button);
}
};
frame.pack();
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setVisible(true);
}
});
}
}

It seems that the problem has something to do with the line: UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); as when I remove it, the buttons are black.
So that is extra information we didn't have before you created the SSCCE (which is why you should always post a SSCCE with your question).
It also tells you the problem is not with your code but with the LAF. The Windows LAF ignores the setBackground(...) method and paints its own background.
One option would be to add an Icon to the button of your desired color. Then you can configure the text to be painted in the center of the button:
import java.awt.*;
import javax.swing.*;
public class ColorIcon implements Icon
{
private Color color;
private int width;
private int height;
public ColorIcon(Color color, int width, int height)
{
this.color = color;
this.width = width;
this.height = height;
}
public int getIconWidth()
{
return width;
}
public int getIconHeight()
{
return height;
}
public void paintIcon(Component c, Graphics g, int x, int y)
{
g.setColor(color);
g.fillRect(x, y, width, height);
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
public static void createAndShowGUI()
{
JPanel panel = new JPanel( new GridLayout(2, 2) );
for (int i = 0; i < 4; i++)
{
Icon icon = new ColorIcon(Color.RED, 50, 50);
JButton label = new JButton( icon );
label.setText("" + i);
label.setHorizontalTextPosition(JButton.CENTER);
label.setVerticalTextPosition(JButton.CENTER);
panel.add(label);
}
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(panel);
f.setSize(200, 200);
f.setLocationRelativeTo( null );
f.setVisible(true);
}
}
Then is should work on all LAF's.

How do you make text in a frame change dependent on cursor position?

I have a program that is basically just supposed to change the text of a label when your cursor enters a polygon that is shown on the JPanel. I have tried a few different things with nothing working. Currently I am trying an if statement to make it choose which button to add but it still doesn't change if i move my cursor into the polygon. when the cursor is outside of the polygon the label should say "point is not in the polygon" and when inside it should say "point is in the polygon". Any help would be greatly appreciated.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Chapter3Lab1 extends JFrame{
private RegularPolygonPanel canvas = new RegularPolygonPanel();
public Chapter3Lab1()
{
JPanel panel = new JPanel();
add(canvas, BorderLayout.CENTER);
add(panel, BorderLayout.SOUTH);
canvas.setFocusable(true);
canvas.requestFocusInWindow();
}
public static void main (String[] args)
{
String isInside = "The point is in the polygon";
String notInside = "The point is not in the polygon";
//Create a Polygon object
Polygon polygon = new Polygon();
polygon.addPoint(40,20);
polygon.addPoint(70,40);
polygon.addPoint(60,80);
polygon.addPoint(45,45);
polygon.addPoint(20,60);
JLabel label = new JLabel(isInside, JLabel.CENTER);
JLabel notlabel = new JLabel(notInside, JLabel.CENTER);
Chapter3Lab1 frame = new Chapter3Lab1();;
frame.setTitle("Chapter 3 Lab 1");
frame.setLayout(new FlowLayout());
frame.setLocationRelativeTo(null);// Center the frame
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(200,200);
while (true)
{
PointerInfo a = MouseInfo.getPointerInfo();
Point b = a.getLocation();
int x = (int) b.getX();
int y = (int) b.getY();
if(polygon.contains(x, y) == false)
{
frame.remove(label);
frame.add(notlabel);
}
else
{
frame.remove(notlabel);
frame.add(label);
}
frame.setVisible(true);
try
{
Thread.sleep(1000);
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
}
class RegularPolygonPanel extends JPanel
{
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
//Create a Polygon object
Polygon polygon = new Polygon();
polygon.addPoint(40,20);
polygon.addPoint(70,40);
polygon.addPoint(60,80);
polygon.addPoint(45,45);
polygon.addPoint(20,60);
//Draw the polygon
g.drawPolygon(polygon);
}
public Dimension getPreferredSize()
{
return new Dimension(200,200);
}
}
}

Start by taking a look at How to Write a Mouse Listener
You will need to maintain a reference to the Polygon object and make use of it's contains method to determine if the mouse is within the Polygon itself...
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Polygon;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private RegularPolygonPanel polyPanel;
private JLabel label;
public TestPane() {
polyPanel = new RegularPolygonPanel();
polyPanel.addMouseMotionListener(new MouseAdapter() {
#Override
public void mouseMoved(MouseEvent e) {
if (polyPanel.isWithinPolygon(e.getPoint())) {
label.setText("Is inside");
} else {
label.setText("Is outside");
}
}
});
label = new JLabel("...");
setLayout(new BorderLayout());
add(polyPanel);
add(label, BorderLayout.SOUTH);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
class RegularPolygonPanel extends JPanel {
private Polygon polygon;
public RegularPolygonPanel() {
//Create a Polygon object
polygon = new Polygon();
polygon.addPoint(40, 20);
polygon.addPoint(70, 40);
polygon.addPoint(60, 80);
polygon.addPoint(45, 45);
polygon.addPoint(20, 60);
}
public boolean isWithinPolygon(Point p) {
return polygon.contains(p);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
//Draw the polygon
g.drawPolygon(polygon);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
}

Image not appearing in jbutton with wordGen

The image isn't being painted when this is run with WordGen, how do i fix this?
When I run this without wordgen I can get the image to appear. I'm not sure what i'm doing wrong since i'm not getting any errors.
Any help is appreciated.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class tfot extends JComponent{
private static final long serialVersionUID = 1L;
public static void main(final String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
showGUI(args);
}
});
}
public static void showGUI(String[] args) {
JPanel displayPanel = new JPanel();
JButton okButton = new JButton("Did You Know?");
okButton.setFont(new Font("Times", Font.TRUETYPE_FONT, 100));
final JLabel jLab = new JLabel();
okButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
jLab.setText(wordGen());
}
});
JPanel content = new JPanel();
content.setLayout(new BorderLayout());
content.add(displayPanel, BorderLayout.CENTER);
content.add(okButton, BorderLayout.SOUTH);
content.add(jLab, BorderLayout.NORTH);
JFrame window = new JFrame("Window");
window.setContentPane(content);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setSize(800, 600);
window.setLocation(400, 300);
window.setVisible(true);
}
#Override
public void paint(Graphics g) {
super.paint(g);
g.drawImage(Toolkit.getDefaultToolkit().getImage("Pictures/background1.png"), 0, 0, this);
}
public static String wordGen() {
String[] wordListOne = {"generic text","hi",};
int oneLength = wordListOne.length;
int rand1 = (int) (Math.random() * oneLength);
String phrase = wordListOne[rand1] + " ";
return phrase;
}
}

First...
Don't load resources or perform long running tasks within the paint methods, these may be called a number of times in quick succession. Instead, load the images before hand and paint them as needed...
public Tfot() {
setLayout(new BorderLayout());
try {
background = ImageIO.read(new File("pictures/background1.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (background != null) {
g.drawImage(background, 0, 0, this);
}
}
Generally, you are discouraged from overriding paint and instead should use paintComponent, lots of reasons, but generally, this is where the background is painted...
Second...
You need to add Tfot to something that is displayable, otherwise it will never be painted
JFrame window = new JFrame("Window");
window.setContentPane(new Tfot());
window.add(content);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setSize(800, 600);
window.setLocation(400, 300);
window.setVisible(true);
Thrid...
JPanel by default is not transparent, you need to set it's opaque property to false
JPanel displayPanel = new JPanel();
displayPanel.setOpaque(false);
//...
JPanel content = new JPanel();
content.setOpaque(false);
Then it will allow what ever is below it to show up (ie, the background image)
Take a look at Painting in AWT and Swing, Performing Custom Painting and Reading/Loading an Image for more details
Fourth...
You need to learn the language basics for embarking on advance topics like GUI and custom painting, without this basic knowledge, this topics will bite you hard.
You need to declare background as a instance field of the class Tfot
private BufferedImage background;
public Tfot() {
Updated - Fully runnable example
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Tfot extends JComponent {
private static final long serialVersionUID = 1L;
public static void main(final String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
showGUI(args);
}
});
}
public static void showGUI(String[] args) {
JPanel displayPanel = new JPanel();
displayPanel.setOpaque(false);
JButton okButton = new JButton("Did You Know?");
okButton.setFont(new Font("Times", Font.TRUETYPE_FONT, 100));
final JLabel jLab = new JLabel();
okButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
jLab.setText(wordGen());
}
});
JPanel content = new JPanel();
content.setOpaque(false);
content.setLayout(new BorderLayout());
content.add(displayPanel, BorderLayout.CENTER);
content.add(okButton, BorderLayout.SOUTH);
content.add(jLab, BorderLayout.NORTH);
Tfot tfot = new Tfot();
tfot.setLayout(new BorderLayout());
tfot.add(content);
JFrame window = new JFrame("Window");
window.setContentPane(tfot);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setSize(800, 600);
window.setLocation(400, 300);
window.setVisible(true);
}
private BufferedImage background;
public Tfot() {
try {
background = ImageIO.read(new File("Pictures/background1.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(background, 0, 0, this);
}
public static String wordGen() {
String[] wordListOne = {"generic text", "hi",};
int oneLength = wordListOne.length;
int rand1 = (int) (Math.random() * oneLength);
String phrase = wordListOne[rand1] + " ";
return phrase;
}
}

Swing - Allowing JButton to always stay on page when scrolling in application

I have this application that I am working on, I have a JFrame that uses a BorderLayout. In the JFrame is a JPanel, the JPanel is using a MigLayout.I am trying to make a JButton stay on the bottom left hand side of the screen , achieving a similar effect as the "position:fixed" property in CSS.
Any tips on how I can achieve this effect by code?
Tried JLayeredPane code from a few other sources, but still doesn't work somehow.
private JPanel contentPane;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if (info.getName().equals("Nimbus")) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
MainFrame frame = new MainFrame();
ForumMainPage panel = new ForumMainPage(frame);
panel.setFocusable(true);
panel.requestFocusInWindow();
frame.add(jLabelOnJButton());
frame.setContentPane(panel);
frame.pack();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public MainFrame() {
Toolkit tk = Toolkit.getDefaultToolkit();
Dimension dim = tk.getScreenSize();
this.setSize(dim);
this.setUndecorated(true);
this.setExtendedState(Frame.MAXIMIZED_BOTH);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLayout(new BorderLayout());
this.add(jLabelOnJButton(),BorderLayout.CENTER);
}
private static JComponent jLabelOnJButton(){
JLayeredPane layers = new JLayeredPane();
JLabel label = new JLabel("label");
JButton button = new JButton("button");
label.setBounds(40, 20, 100, 50);
button.setBounds(100, 20, 150, 75);
layers.add(label, new Integer(200));
layers.add(button, new Integer(100));
return layers;
}
}
Thanks in advance!

You could add the button to the frame's glass pane. This takes a little bit of work to make happen, as you need to keep track of the scroll pane relative to the glass pane, but it should achieve the desired effect
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class OverlayButton {
public static void main(String[] args) {
new OverlayButton();
}
public OverlayButton() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JScrollPane sp;
private JButton btn;
private JTextArea ta;
private JPanel glassPane;
public TestPane() {
setLayout(new BorderLayout());
btn = new JButton("Print");
ta = new JTextArea(10, 20);
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader(new File("Script.txt")));
String text = null;
while ((text = br.readLine()) != null) {
ta.append(text + "\n");
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
br.close();
} catch (Exception e) {
}
}
ta.setCaretPosition(0);
sp = new JScrollPane(ta);
glassPane = new JPanel() {
#Override
public void doLayout() {
Point p = sp.getLocation();
Dimension dim = sp.getSize();
p = SwingUtilities.convertPoint(sp, p, this);
btn.setSize(btn.getPreferredSize());
int barWidth = sp.getVerticalScrollBar().getWidth();
int barHeight = sp.getHorizontalScrollBar().getHeight();
int x = p.x + (dim.width - btn.getWidth()) - barWidth;
int y = p.y + (dim.height - btn.getHeight()) - barHeight;
btn.setLocation(x, y);
}
};
glassPane.setOpaque(false);
glassPane.add(btn);
glassPane.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent e) {
e.getComponent().doLayout();
}
});
add(sp);
}
#Override
public void addNotify() {
super.addNotify();
SwingUtilities.getRootPane(this).setGlassPane(glassPane);
glassPane.setVisible(true);
glassPane.revalidate();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.dispose();
}
}
}
Take a look at How to use Root Panes for more details

Try using the OverlayLayout:
JPanel contentPane = new JPanel();
contentPane.setLayout( new OverlayLayout(ContentPane) );
frame.setContentPane( panel );
JButton button = new JButton(...);
button.setAlignmentX(0.0f);
button.setAlignmentY(1.0f);
contentPane.add( button );
ForumMainPage panel = new ForumMainPage(frame);
contentPane.add( panel );