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JFrame (Swing) update(graphics) error

I have a little game with little Rect, which are moving and I need to update the Graphics by doing this.update(MyGraphics) in my onUpdate method, which gets called every 50 millisekonds. But when I do this this.update(MyGraphics) all my buttons and textfields are glitched.
Does somebody have an idea how to fix it?

when I do this this.update(MyGraphics) all my buttons and textfields are glitched.
Don't invoke update(...) directly. That is not the way custom painting is done.
Instead when you do custom painting you override the paintComponent(...) method of the JPanel:
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
// add your custom painting here
}
I have a little game with little Rect, which are moving
If you want animation then you should use a Swing Timer to schedule the animation. Then when the Timer fires you invoke a method on your custom class to change the location of the rectangle and then you invoke repaint(). This will cause the panel to be repainted.
Read the Swing Tutorial. There are sections on:
Performing Custom Painting
How to Use Swing Timers
to get your started with basic examples.

Here is one of the examples how to update JPanel by a timer.
import java.awt.Color;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class MainClass extends JPanel {
static JFrame frame = new JFrame("Oval Sample");
static MainClass panel = new MainClass(Color.CYAN);
static Color colors[] = {Color.RED, Color.BLUE, Color.GREEN, Color.YELLOW};
static Color color;
static int step = 0;
public MainClass(Color color) {
this.color = color;
}
final static Timer tiempo = new Timer(500, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
// paintComponent();
System.out.println("Step: " + step++);
if (step % 2 == 0) {
color = Color.DARK_GRAY;
} else {
color = Color.BLUE;
}
panel.repaint();
}
});
#Override
public void paintComponent(Graphics g) {
int width = getWidth();
int height = getHeight();
g.setColor(color);
g.drawOval(0, 0, width, height);
}
public static void main(String args[]) {
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new GridLayout(2, 2));
panel = new MainClass(colors[2]);
frame.add(panel);
frame.setSize(300, 200);
frame.setVisible(true);
tiempo.start();
}
}

JFrame does not add component when JButton is pressed

My code is basically about having a frame and it has a button. You press the button you can draw rectangles, getting coordinates from the mouse press and the mouse release.
Now, if you remove the button the code works perfectly, here is the code.
//testing file
package ActionTest;
import java.awt.*;
import javax.swing.*;
public class MouseTest
{
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
JFrame frame = new MouseFrame();
frame.setTitle("MouseTest");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.setSize(500,500);
}
});
}
}
My frame, calls on the mouse component
package ActionTest;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class MouseFrame extends JFrame
{
public MouseFrame()
{
add(new MouseComponent());
}
}
The component class: handles mouse clicks and drawing the rectangle
package ActionTest;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import javax.swing.*;
public class MouseComponent extends JComponent
{
Point first;
Point second;
private ArrayList<Rectangle2D> rectangles;
public MouseComponent()
{
rectangles = new ArrayList<>();//contains rectangles
addMouseListener(new MouseHandler());
}
//paint method of the component, simply re-paint the array
public void paintComponent(Graphics g)
{
Graphics2D g2 = (Graphics2D) g;
for (Rectangle2D r : rectangles)
g2.draw(r);
}
/**
* creates a rectangle and adds it to the rectangles ArrayList
* then repaint the component
* inside some operations to deal with rectangle drawing nothing to do with the issue
* #param p1: first coordinates
* #param p2: second coordinates
*/
public void addRec(Point2D p1, Point2D p2)
{
double w, h, x, y;
double x1 = p1.getX();
double y1 = p1.getY();
double x2 = p2.getX();
double y2 = p2.getY();
if(x1 <= x2){
x = x1;
w = x2-x1;
}
else{
x = x2;
w = x1-x2;
}
if (y1 <= y2){
y = y1;
h = y2-y1;
}
else{
y = y2;
h = y1-y2;
}
rectangles.add(new Rectangle2D.Double(x, y, w, h));
repaint();
}
//records mouse click and mose release
//you press the mouse that is the 1st coordinates
//you release it that is the 2nd coordinates
//pass both to the addRec method
private class MouseHandler extends MouseAdapter
{
#Override
public void mousePressed(MouseEvent event)
{
first = event.getPoint();
}
#Override
public void mouseReleased(MouseEvent event)
{
second = event.getPoint();
addRec(first, second);
}
}
}
It works perfectly. However, going back to the original problem, if I add a button, and then when the button pressed go ahead and begin drawing rectangles it doesn't work.
Here is the modified frame class
package ActionTest;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class MouseFrame extends JFrame
{
private JPanel buttonPanel;
public MouseFrame()
{
JFrame frame = this;
buttonPanel = new JPanel();
JButton rec = new JButton("Rectangle");
rec.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent event)
{
System.out.println("pressed");
frame.add(new MouseComponent());
}});
buttonPanel.add(rec);
add(buttonPanel);
}
}
Thanks in advance.

frame.add(new MouseComponent());
The size of a newly created component is (0, 0) so there is nothing to paint. So you need to invoke the layout manager when you add a component to a visible GUI.
frame.add(new MouseComponent());
frame.revalidate();
frame.repaint();
Note this will only work if the layout manager allows you to add multiple components to the frame. The default layout manager for a frame is the BorderLayout and only a single components can be added to the CENTER of the BorderLayout.
So maybe you need to add the button using:
frame.add(button, BorderLayout.PAGE_START);
Read the section from the Swing tutorial on How to Use Layout Managers for more information and working examples.
Also, any time you do custom painting you need to override the getPreferredSize() method of the custom component so the layout managers can do their job.

Java: Using graphics component within an ActionListener

I have two separate class and driver files, and in the class file I create the paint method:
public void paint(Graphics g){
g.drawLine(......
....
//along with all of my other draw commands
}
Further down in the code, I create a JButton and within this button's action listener I don't know how to use a Graphics object to create more graphics in the JFrame. Should I be adding something to my driver to make this happen, or is there a way to use these graphics within my action listener? Thank you, and any help is appreciated.

You need to draw everything within the paint method. The actionPerformed should only change the state of something already in the paint method, and then call repaint. For example
boolean drawHello = true;
boolean drawWorld = false;
protected void paintComponent(Graphics g) {
super.paintCompoent(g);
if (drawHello)
g.drawString("Hello", 50, 50);
if (drawWorld)
g.drawString("World", 10, 10);
}
Then in your actionPerformed, you can change the state of drawWorld to true and call repaint().
public void actionPerformed(ActionEvent e) {
drawWorld = true;
repaint();
}
So as you can see, everything should be drawn in the paintComponent method. You can just hide and paint renderings, and make them "visible" from a action command. You should already have predefined what could posibly be drawn. Then just change the state of it rendering
And as #MadPrgrammer pointed out, you should not be painting on top-level containers like JFrame. Instead paint on a custom JPanel or JComponent and override the paintComponent method, instead of JFrame and paint
Here's an example where I draw a new square every time the button is pressed. If look at the code, you will see that in the paintComponent method, I loop through a list of Squares and draw them, and in the actionPerformed all I do is add a new Square to the List and call repaint()
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class AddSquares {
private int R = 0;
private int G = 0;
private int B = 0;
private int xLoc = 0;
private int yLoc = 0;
List<Square> squares = new ArrayList<>();
private JButton addSquare = new JButton("Add Square");
private RectsPanel panel = new RectsPanel();
public AddSquares() {
addSquare.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
Color color = new Color(R, G, B);
squares.add(new Square(xLoc, yLoc, color));
panel.repaint();
R += 10;
G += 20;
B += 30;
xLoc += 20;
yLoc += 20;
}
});
JFrame frame = new JFrame("Draw Squares");
frame.add(panel, BorderLayout.CENTER);
frame.add(addSquare, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
private class RectsPanel extends JPanel {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (Square square : squares) {
square.drawSquare(g);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(250, 250);
}
}
private class Square {
int x = 0;
int y = 0;
Color color;
public Square(int x, int y, Color color) {
this.x = x;
this.y = y;
this.color = color;
}
public void drawSquare(Graphics g) {
g.setColor(color);
g.fillRect(x, y, 75 ,75);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
AddSquares addSquares = new AddSquares();
}
});
}
}

It's difficult to be 100%, but it would seem as you don't understand how custom painting is performed in Swing.
Start by taking a look at Performing Custom Painting and Painting in AWT and Swing.
Essentially, painting is arranged by the Repaint Manager, which decides what and when something should be painted. It then calls (through a chain of methods) the paint method of the components it thinks need to be updated, passing it a reference to a Graphics context that should be used to actually paint on.
Basically, when ever your paint method is called, you should create paint the current state of your painting.
You should avoid overriding paint and instead use paintComponent from classes the extend JComponent

Your question is a little on the vague side as to what you are actually wondering about but generally speaking:
We don't override paint in Swing, we override paintComponent.
If you are already aware of this, you may be overriding paint because you are doing it on a JFrame and you found that JFrame does not have a paintComponent method. You shouldn't override paint on a JFrame. Instead, create a JPanel or something to put inside the frame and override paintComponent on the panel.
Question about the ActionListener.
It sounds like you are wanting to do painting outside of paintComponent in which case probably the best way is to do painting to a separate Image. Then you paint the Image on to the panel in paintComponent. You can also put an Image in a JLabel as an ImageIcon. Here is a very simple drawing program using MouseListener that demonstrates this (taken from here):
import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
class PaintAnyTime {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new PaintAnyTime();
}
});
}
final BufferedImage image = (
new BufferedImage(500, 500, BufferedImage.TYPE_INT_ARGB)
);
final JFrame frame = new JFrame();
final JLabel label = new JLabel(new ImageIcon(image));
final MouseAdapter drawer = new MouseAdapter() {
Graphics2D g2D;
#Override
public void mousePressed(MouseEvent me) {
g2D = image.createGraphics();
g2D.setColor(Color.BLACK);
}
#Override
public void mouseDragged(MouseEvent me) {
g2D.fillRect(me.getX(), me.getY(), 3, 3);
label.repaint();
}
#Override
public void mouseReleased(MouseEvent me) {
g2D.dispose();
g2D = null;
}
};
PaintAnyTime() {
label.setPreferredSize(
new Dimension(image.getWidth(), image.getHeight())
);
label.addMouseListener(drawer);
label.addMouseMotionListener(drawer);
frame.add(label);
frame.pack();
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
#MadProgrammer has already linked to the articles that I was going to link to.

JButton subclass with custom shape shifts during repainting

I have just started working with Swing and am trying to draw a button with a custom shape, a triangle in this example. I called the JButton subclass 'ShiftingButton' in the following code because of its unusual behavior. When the mouse enters its region, it is repainted with an offset from its original position. Furthermore the shifted, offset version is drawn in addition to the original position so that both the original and shifted versions appear together. That is, when I run this code, the button is shown as a triangle along the left edge of the window. Then when I run the mouse over the button, a new triangle is drawn (in addition to the old one), shifted down and to the right by about 10 pixels. Resizing the window changes the offset of the phantom button from the original.
Experimenting with mouse clicks shows that only the original, correctly-positioned button is active. The region of the offset phantom button is not active.
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.event.*;
import java.awt.Polygon;
public class ShiftingButton extends JButton implements ActionListener {
private Polygon shape;
public ShiftingButton () {
initialize();
addActionListener(this);
}
protected void initialize() {
shape = new Polygon();
setSize(120, 120);
shape.addPoint(0, 0);
shape.addPoint(0, 60);
shape.addPoint(90, 0);
setMinimumSize(getSize());
setMaximumSize(getSize());
setPreferredSize(getSize());
}
// Hit detection
public boolean contains(int x, int y) {
return shape.contains(x, y);
}
#Override
public void paintComponent (Graphics g) {
System.err.println("paintComponent()");
g.fillPolygon(shape);
}
protected void paintBorder(Graphics g) {
}
#Override
public void actionPerformed (ActionEvent ev) {
System.out.println("ShiftingButton ActionEvent!");
}
public static void main (String[] args) {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
ShiftingButton button = new ShiftingButton();
panel.add(button);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
}

You failed to call super.paintComponent(g) inside the overridden paintComponent(...) method. Moreover, while overriding a method of the Base class, always try to keep the access specifier of the methods, the same, as much as possible. In this case it's protected and not public :-) Now function should be like this :
#Override
protected void paintComponent (Graphics g) {
System.err.println("paintComponent()");
super.paintComponent(g);
g.fillPolygon(shape);
}
EDIT 1 :
Moreover, since you are using a custom shape to be drawn, hence you again failed to specify the ContentAreaFilled property for this JButton in question, hence inside your constructor, you should write setContentAreaFilled(false), for it to work nicely. Though if this doesn't works (for reasons specified in the Docs), then you have to use the plain old Opaque property and set it to false for this JButton using setOpaque(false) :-)
Here is your code with modified changes :
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.event.*;
import java.awt.Polygon;
public class ShiftingButton extends JButton implements ActionListener {
private Polygon shape;
public ShiftingButton () {
setContentAreaFilled(false);
initialize();
addActionListener(this);
}
protected void initialize() {
shape = new Polygon();
setSize(120, 120);
shape.addPoint(0, 0);
shape.addPoint(0, 60);
shape.addPoint(90, 0);
}
#Override
public Dimension getPreferredSize() {
return (new Dimension(120, 120));
}
// Hit detection
public boolean contains(int x, int y) {
return shape.contains(x, y);
}
#Override
protected void paintComponent(Graphics g) {
System.err.println("paintComponent()");
super.paintComponent(g);
g.fillPolygon(shape);
}
protected void paintBorder(Graphics g) {
}
#Override
public void actionPerformed (ActionEvent ev) {
System.out.println("ShiftingButton ActionEvent!");
}
public static void main (String[] args) {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
ShiftingButton button = new ShiftingButton();
panel.add(button);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
}

MouseListener Help Java

I am trying to write a program in Java Swing that outputs a 10 x 10 grid of geometric rectangles filled with randoms colors. However, when the user clicks on one of the rectangles within the display window the rectangle should repaint() and change to another color.
Thus far I have the rudimentary program running, but I can't figure out how to implement a mouseListener to it in order to have the rectangles' color change when a user clicks inside. At this point, the rectangles only repaint when the display window is expanded and minimized. Any advice/help would be greatly appreciated! Thanks!
Here is what I have so far...
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.geom.*;
public class ColorGrid extends JPanel {
int w, x, y, z;
Color c = new Color((int)(Math.random() * 0xFFFFFF));
public void paint(Graphics g){
Graphics2D g2 = (Graphics2D) g;
setLayout(new GridLayout(10,10));
int w = x = y = z = 0;
for(int i=0;i<100;i++){
Color c = new Color((int)(Math.random() * 0xFFFFFF));
w+=10;
x+=10;
y+=50;
z+=15;
g2.drawRect(w+10,x+30,y,z);
g2.drawRect(w+10,x+30,y,z);
g2.fillRect(w+10,x+30,y,z);
g2.setPaint(c);
}
}
public static void main(String[] args) {
JFrame f= new JFrame();
f.setTitle("ColorGrid Display Window");
f.setSize(200,200);
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
Container contentPane = f.getContentPane();
contentPane.add(new ColorGrid());
f.show();
}
}

Any Component can have a MouseListener. JLabel is nice for a colored rectangle, as long as you make it opaque.
Addendum: Having recommended MouseAdapter elsewhere, I should mention that one instance is enough.
Addendum: This update adds the mouse listener in the ColorLabel constructor.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JLabel;
/** #see http://stackoverflow.com/questions/5136859 */
public class ColorLabel extends JLabel {
private static final int N = 10;
private static final Random random = new Random();
private static final MouseAdapter listener = new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
ColorLabel label = (ColorLabel) e.getSource();
label.setBackground(new Color(random.nextInt()));
}
};
public ColorLabel() {
this.setOpaque(true);
this.setBackground(new Color(random.nextInt()));
this.setPreferredSize(new Dimension(32, 32));
this.addMouseListener(listener);
}
private void displayGrid() {
JFrame f = new JFrame("ColorGrid");
f.setLayout(new GridLayout(N, N));
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
for (int i = 0; i < N * N; i++) {
final ColorLabel label = new ColorLabel();
f.add(label);
}
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new ColorLabel().displayGrid();
}
});
}
}

Instead of having a JPanel that you draw your grid of colors on, how about you have a grid of buttons. You override the drawing mechanism for the button so that it just renders as it's current color. Then you have functionality built in to listen for clicks to occur in a specific section of your grid.

This is what I came up with.
Note: I'm still studying Java in University, so this might not be the exact way to do this but it worked when I did it.
public class ColorGrid extends JPanel implements MouseListener {
this.addMouseListener(this);
addMouseListener(this);
That's the first part, the second part is to have these methods in your code.
public void mouseClicked(MouseEvent arg0) {
}
public void mouseEntered(MouseEvent arg0) {
}
public void mouseExited(MouseEvent arg0) {
}
public void mousePressed(MouseEvent arg0) {
}
public void mouseReleased(MouseEvent arg0) {
}
Then, depending on what you want, (i.e. Mouse clicked or pressed), just type in:
repaint();
Hope this helped.

Assuming you have a 2d array of colors, you can simply use the x and y the mouselistener gives you when you click to calculate the indices of that rectangle. Just divide the x and y by the size of the rectangle using integer division. After changing the color use repaint() to show it.