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repaint() - component doesn't appear for a simple show

I'm trying to code an Othello, and... I'm already stuck with a basic view.
My main class:
public class Othello extends JFrame {
private static final long serialVersionUID = 1L;
public static final int WIDTH = 800;
public static final int HEIGHT = 600;
private Grid grid;
public Othello() {
this.setSize(WIDTH, HEIGHT);
this.setTitle("Othello");
this.grid = new Grid();
this.setContentPane(this.grid);
this.grid.revalidate();
this.grid.repaint();
}
public void run() {
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setResizable(false);
this.setVisible(true);
}
public static void main(String[] args) {
new Othello().run();
}
}
And my JPanel class:
public class Grid extends JPanel {
private static final long serialVersionUID = 1L;
public Grid() {}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(new Color(0,128,0));
g.fillRect(0, 0, WIDTH, HEIGHT);
}
}
I don't understand why it doesn't show anything.
The paintComponent is called, but nothing happens, I tried to call revalidate() and repaint() almost everywhere and nothing works.
I've been looking for the solution in different topics for almost 1 hour, and none of the solution I've found worked.

This is your problem:
g.fillRect(0, 0, WIDTH, HEIGHT);
The WIDTH and HEIGHT values are not what you expect them to be, and in fact they are likely both 0. Instead for safest programming, you need to get the actual width and height via getWidth() and getHeight()
No need for those revalidate()s and repaint()s. For example:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.*;
public class GridTest {
private static final int WIDTH = 800;
private static final int HEIGHT = 600;
private static void createAndShowGui() {
Grid mainPanel = new Grid(WIDTH, HEIGHT);
JFrame frame = new JFrame("Grid Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
class Grid extends JPanel {
private static final long serialVersionUID = 1L;
private int prefW;
private int prefH;
public Grid(int prefW, int prefH) {
this.prefW = prefW;
this.prefH = prefH;
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(new Color(0,128,0));
g.fillRect(0, 0, getWidth(), getHeight());
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(prefW, prefH);
}
}
Also there really is no need to override paintComponent if all you're doing is filling the background. A call to setBackground(new Color(0, 128, 0)); within the Grid constructor will set it. Of course you might need the paintComponent if you're going to draw other things -- but if it's a grid, consider using a grid of JLabels and setting their icons.

Resize a JPanel BorderLayout Java

I try to use swing and I have a litle problem that I fail to solve. That I want to do is simple: I just want to had to JPanel in a JFrame using BorderLayout.
The problem is my center panel is always placed above my North Jpanel. In fact whatever the size I give my north panel just have like 10 pixel, after the center pannel beggin (like on this image).
Note: when I put my second panel south the first panel have enough place to be drawn but even if it has more place the second one also take just 10 pixel which is not enough (like on this image).
this is my Plateau constructor class which extends JFrame:
public Plateau(){
super("arkanoid");
this.setLayout(new BorderLayout());
setFocusable(true);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.getContentPane().add(affich,BorderLayout.NORTH);
this.getContentPane().add(jeu, BorderLayout.CENTER);
setVisible(true);
this.setResizable(false);
this.setMinimumSize(new Dimension(700,800));
this.setLocationRelativeTo(null);
}
here a part of my panel placed in center (the rest is dvariable modification and drawing functions):
public class Jeu extends JPanel {
public Jeu(int score, int plateauX, int balleX, int balleY, boolean perdu){
super();
}
public void paint(Graphics g){
Graphics2D g2 = (Graphics2D)g;
this.setSize(new Dimension(Width,Heigth));
}
}
and here is all my class supposed to be on north:
public class Affich extends JPanel {
public Affich() {
super();
this.setSize(100,100);
}
public void paint(Graphics g){
this.setSize(100,100);
g.drawOval(0, 0, 50, 50);
}
}
I hope I was clear enough

NEVER call setSize(...) or anything like it within a painting method. These methods should be for painting and painting only, and if you try to change size state, you can end up with a vicious cycle of endless calls -- set size which calls repaint which sets size, which calls repaint.
Instead:
Override the JPanel's paintComponent not paint, since paint is responsible for more than painting the JPanel, and overriding it can have unintended consequences on the JPanel's borders and child components.
Call the super's paintComponent within the override
Again, do only painting within a painting method
Don't set size but instead set preferred size and from code that is called once, and not within a painting method.
For example
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import javax.swing.*;
public class MyDrawing {
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
JFrame frame = new JFrame("GUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
int affichW = 100;
int affichH = 100;
Affich affich = new Affich(affichW , affichH );
Jeu jeu = new Jeu();
frame.add(affich, BorderLayout.PAGE_START);
frame.add(jeu, BorderLayout.CENTER);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
}
#SuppressWarnings("serial")
class Jeu extends JPanel {
private static final int JEU_W = 600;
private static final int JEU_H = 450;
public Jeu(int score, int plateauX, int balleX, int balleY, boolean perdu) {
super();
setBorder(BorderFactory.createTitledBorder("Jeu"));
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
} else {
return new Dimension(JEU_W, JEU_H);
}
}
public Jeu() {
this(0, 0, 0, 0, false);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
// draw with g2 here
}
}
#SuppressWarnings("serial")
class Affich extends JPanel {
private int width = 0;
private int height = 0;
public Affich(int width, int height) {
super();
this.width = width;
this.height = height;
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
} else {
return new Dimension(width, height);
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
// draw smooth oval
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g.drawOval(0, 0, 50, 50);
}
}

Errors with setFrame, JSlider

So I am testing out a JSlider for a bigger project and can't get it to work. The slider is supposed to adjust the size of a circle, and it's not working. I thought I might have an issue with the creation of the circle, and I am trying to use setFrame, and it's giving an error saying it's "undefined." Can anyone see why? Since it should take in either float or double as parameters. Or if you can see why it's not adjusting the size of the shape that would help a lot too... Here's what I have:
public class DrawShape extends JPanel{
private float width = 300;
private Shape circle = new Ellipse2D.Float(100, 20, width, 300);
public DrawShape() {
}
public DrawShape(float width) {
this.width = width;
}
public void setWidth(int w) {
this.width = w;
circle.setFrame(100, 20, width, 300);//This is where the error is
}
public void paintComponent (Graphics g) {
super.paintComponents(g);
Graphics2D graphics = (Graphics2D)g;
graphics.setColor(Color.black);
graphics.fill(circle);
}//end paintComponent
}//end class
Class with main:
public class SliderTest extends JFrame{
private static DrawShape circle = new DrawShape();
JSlider slider;
JLabel label;
public SliderTest() {
setLayout(new FlowLayout());
slider = new JSlider(JSlider.HORIZONTAL, 150, 450, 300);//orientation, min val, max value, starting val
slider.setMajorTickSpacing(50);//every 5 integers will be a new tick position
slider.setPaintTicks(true);
add(slider);
label = new JLabel("Current value 300");
add(label);
event e = new event();
slider.addChangeListener(e);;
}//end cons
public class event implements ChangeListener{
public void stateChanged(ChangeEvent e) {
JSlider slider = (JSlider)e.getSource();
int value = slider.getValue();
label.setText("Current Value " + value);
circle.setWidth(value);
repaint();
}//end stateChanged
}//end class event
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setTitle("Circle");
frame.add(circle);
frame.setSize(500,400);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
JFrame frame1 = new SliderTest ();
frame1.setTitle("Toolbar");
frame1.setSize(300,200);
frame1.setLocation(200,100);
frame1.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame1.setVisible(true);
}
}

Shape does not have a setFrame method. RectangularShape does...
Instead of
private Shape circle = new Ellipse2D.Float(100, 20, width, 300);
You might try using...
private Ellipse2D circle = new Ellipse2D.Float(100, 20, width, 300);
instead...
Your public DrawShape(float width) { constructor is also wrong, as it does not actually do anything.
You should also consider overriding the getPreferredSize method so it can return the width of the shape as a part of the preferred size.
I'm not sure you actually need to maintain the width reference as you can ascertain this from the circle directly...IMHO
For Example
I've not tested this...
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Ellipse2D;
import javax.swing.JPanel;
public class DrawShape extends JPanel {
private final Ellipse2D circle = new Ellipse2D.Float(100, 20, 300, 300);
public DrawShape() {
}
public DrawShape(float width) {
circle.setFrame(100, 20, width, 300);
}
public void setWidth(int w) {
circle.setFrame(100, 20, w, 300);
revalidate();
}
#Override
public Dimension getPreferredSize() {
Dimension size = super.getPreferredSize();
size.width = circle.getBounds().width;
return size;
}
#Override
public void paintComponent(Graphics g) {
super.paintComponents(g);
Graphics2D graphics = (Graphics2D) g;
graphics.setColor(Color.black);
graphics.fill(circle);
}//end paintComponent
}//end class

Why do I have one scrollPanel which works and another which doesn't?

I have the one big panel on the left with a scrollPanel wrapped around it and it works fine; but in the upper right corner I have a panel which is also supposed to have a scrollPanel, but I cant seem to get it so that the scrollbars can actually move. They just stay full and unmovable. Can someone please help me work out why this is?
This scrollPanel is the one causing issues:
public MapBuilderSidePanel(Dimension size){
tileSetPanel = new MapBuilderTileSetPanel(new Dimension(tileSetPanelWidth,tileSetPanelHeight),6,17, tileSetPanelHeight, tileSetPanelWidth, this);
scrollPane = new JScrollPane(tileSetPanel, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
//add(tileSet, BorderLayout.NORTH);
add(scrollPane, BorderLayout.CENTER);
setPreferredSize(size);
setBorder(new BevelBorder(BevelBorder.LOWERED));
setVisible(true);
}
This is the code for my little application, I've tried to strip out as much as possible. It is copy paste compile and runnable.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Rectangle;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.border.BevelBorder;
public class MapBuilderFrame extends JFrame {
/**
* #param args
*/
private String frameTitle = "Yoonsio Map Editor";
private int frameWidth = 1000;
private int frameHeight = 1000;
private MapBuilderPanel mainPanel;
private MapBuilderSidePanel myLeftSidePanel;
private MapBuilderSidePanel myRightSidePanel;
private JScrollPane scrollPane;
public MapBuilderFrame() {
myRightSidePanel = new MapBuilderSidePanel(new Dimension(200,2000));
mainPanel = new MapBuilderPanel(myRightSidePanel);
setTitle(frameTitle);
setSize(frameWidth,frameHeight);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
setPreferredSize(new Dimension(450, 110));
setResizable(false);
scrollPane = new JScrollPane(mainPanel,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
add(scrollPane, BorderLayout.CENTER);
add(myRightSidePanel, BorderLayout.EAST);
}
public static void main(String[] args) {
new MapBuilderFrame();
}
}
/***************************************************************************/
class MapBuilderPanel extends JPanel {
/**
* #param args
*/
private final int NUMERIC_TO_ASCII_OFFSET = 96;
private MapBuilderSidePanel mySidePanel;
private Rectangle hoverRect;
public MapBuilderPanel(MapBuilderSidePanel mySidePanel){
this.mySidePanel = mySidePanel;
setPreferredSize(new Dimension(2000,2000));
setBackground(new Color(0x00006595));
}
public void refresh(){
this.repaint();
}
public void paint(Graphics g){
g.setColor(new Color(0x00006595));
g.fillRect(0, 0, 2000, 2000);
}
}
/***************************************************************************/
class MapBuilderSidePanel extends JPanel {
/* Ypos = the Y position counter used to draw the grid*/
private MapBuilderTileSetPanel tileSetPanel;
/* Width and Heights pertaining to the tileset grid */
private int tileSetPanelHeight = 400;
private int tileSetPanelWidth = 175;
private JScrollPane scrollPane;
/*only constructor needed*/
public MapBuilderSidePanel(Dimension size){
tileSetPanel = new MapBuilderTileSetPanel(new Dimension(tileSetPanelWidth,tileSetPanelHeight),6,17, tileSetPanelHeight, tileSetPanelWidth, this);
scrollPane = new JScrollPane(tileSetPanel, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
//add(tileSet, BorderLayout.NORTH);
add(scrollPane, BorderLayout.CENTER);
setPreferredSize(size);
setBorder(new BevelBorder(BevelBorder.LOWERED));
setVisible(true);
}
// Remember override paintComponent(); NOT paint().
public void paintComponent(Graphics g){
}
public void loadTileSet(String filename, int r, int c){
//tileSet.loadTileSet(filename, r, c);
}
public void refresh(){
tileSetPanel.repaint();
}
}
/***************************************************************************/
class MapBuilderTileSetPanel extends JPanel{
private MapBuilderSidePanel myParent;
MapBuilderTileSetPanel(Dimension size, int columns, int rows, int parentPanelHeight, int parentPanelWidth, MapBuilderSidePanel mp){
this.myParent = mp;
setBackground(Color.BLACK);
setPreferredSize(size);
setSize(1000,1000);
setBorder(new BevelBorder(BevelBorder.LOWERED));
}
public void loadTileSet(String filename, int c, int r){
}
public void paintComponent(Graphics g){
g.setColor(new Color(0x00550055));
g.drawRect(25, 25, 25, 25);
g.setColor(new Color(0x0000FF00));
g.drawRect(30, 30, 200, 500);
}
public MapBuilderTileSetPanel returnThis() {
return this;
}
}

You may be looking for JScrollNavigator, examined here.
Notes on your SSCCE:
Swing GUI objects should be constructed and manipulated only on the event dispatch thread.
"Swing programs should override paintComponent() instead of overriding paint()."—Painting in AWT and Swing: The Paint Methods.
Don't use setPreferredSize() when you really mean to override getPreferredSize(), as discussed here.
The scrollbar will appear automatically whenever the scrollpane is smaller than the enclosed component, as noted here.

Your scrollPane have no preffered size, so it is scaling to inner component.
Add:
scrollPane.setPreferredSize( new Dimension(200, 200));
Also as mKorbel pointed, call upper class method when you ovveride it.

about drawing a Polygon in java

hi there i'm trying to improve myself about java2D and first of all i'm dealing with drawing polygons. However, i can not see the polygon on frame. I read some tutorials and examples but as i said i face with problems. here is the sample code of drawing a polygon;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Polygon;
import javax.swing.JFrame;
public class jRisk extends JFrame {
private JFrame mainMap;
private Polygon poly;
public jRisk(){
initComponents();
}
private void initComponents(){
mainMap = new JFrame();
mainMap.setSize(800, 600);
mainMap.setResizable(false);
mainMap.setVisible(true);
mainMap.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
int xPoly[] = {150,250,325,375,450,275,100};
int yPoly[] = {150,100,125,225,250,375,300};
poly = new Polygon(xPoly, yPoly, xPoly.length);
}
protected void paintComponent(Graphics g){
super.paintComponents(g);
g.setColor(Color.BLUE);
g.drawPolygon(poly);
}
/**
* #param args
*/
public static void main(String[] args) {
new jRisk();
}
}

JFrame does not have a paintComponent(Graphics g) method. Add the #Override annotation and you will get a compile time error.
1) Use JPanel and override paintComponent (you would than add JPanel to the JFrame viad JFrame#add(..))
2) Override getPreferredSize() to return correct Dimensions which fit your drawing on Graphics object or else they wont be seen as JPanel size without components is 0,0
3) dont call setSize on JFrame... rather use a correct LayoutManager and/or override getPrefferedSize() and call pack() on JFrame after adding all components but before setting it visible
4) Have a read on Concurrency in Swing specifically about Event Dispatch Thread
5) watch class naming scheme should begin with a capital letter and every first letter of a new word thereafter should be capitalized
6) Also you extend JFrame and have a variable JFrame? Take away the extend JFrame and keep the JFrame variable as we dont want 2 JFrames and its not good practice to extend JFrame unless adding functionality
Here is your code with above fixes (excuse picture quality but had to resize or it was going to 800x600):
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Polygon;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class JRisk {
private JFrame mainMap;
private Polygon poly;
public JRisk() {
initComponents();
}
private void initComponents() {
mainMap = new JFrame();
mainMap.setResizable(false);
mainMap.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
int xPoly[] = {150, 250, 325, 375, 450, 275, 100};
int yPoly[] = {150, 100, 125, 225, 250, 375, 300};
poly = new Polygon(xPoly, yPoly, xPoly.length);
JPanel p = new JPanel() {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLUE);
g.drawPolygon(poly);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 600);
}
};
mainMap.add(p);
mainMap.pack();
mainMap.setVisible(true);
}
/**
* #param args
*/
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new JRisk();
}
});
}
}
As per your comment:
i am preparing a map which includes lots of polygons and yesterday i
used a JPanel over a JFrame and i tried to check if mouse was inside
of the polygon with MouseListener. later i saw that mouseListener gave
false responds (like mouse is not inside of the polygon but it acts
like it was inside the polygon). so i deleted the JPanel and then it
worked
Here is updated code with MouseAdapter and overridden mouseClicked to check if click was within polygon.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Polygon;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class JRisk {
private JFrame mainMap;
private Polygon poly;
public JRisk() {
initComponents();
}
private void initComponents() {
mainMap = new JFrame();
mainMap.setResizable(false);
mainMap.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
int xPoly[] = {150, 250, 325, 375, 450, 275, 100};
int yPoly[] = {150, 100, 125, 225, 250, 375, 300};
poly = new Polygon(xPoly, yPoly, xPoly.length);
JPanel p = new JPanel() {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.BLUE);
g.drawPolygon(poly);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 600);
}
};
MouseAdapter ma = new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent me) {
super.mouseClicked(me);
if (poly.contains(me.getPoint())) {
System.out.println("Clicked polygon");
}
}
};
p.addMouseListener(ma);//add listener to panel
mainMap.add(p);
mainMap.pack();
mainMap.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new JRisk();
}
});
}
}

JFrame does not extend JComponent so does not override paintComponent. You can check this by adding the #Override annotation.
To get this functionality extract paintComponent to a new class which extends JComponent. Don't forget to call super.paintComponent(g) rather than super.paintComponents(g).

Replace
protected void paintComponent(Graphics g){
super.paintComponents(g);
g.setColor(Color.BLUE);
g.drawPolygon(poly);
}
With
protected void paint(Graphics g){
super.paint(g);
g.setColor(Color.BLUE);
g.drawPolygon(poly);
}