Why Can't I draw line On JFrame - java

As shown below in code, i'm getting x and y values of line from the database. And then storing them in an array x. After that i'm trying to draw this line on the Frame, but it is not getting drawn. How can i draw line on Frame?
public class TestFrame{
static JFrame test;
public static void main(String ar[]){
test=new JFrame("Test");
JButton openLine=new JButton(new AbstractAction("Open Line"){
public void actionPerformed(ActionEvent e) {
String lineId=JOptionPane.showInputDialog("Enter Line id");
ImageComponent image=new ImageComponent();
image.openLine(lineId);
}
});
test.add(openLine, BorderLayout.NORTH);
test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
test.setSize(600,600);
test.setVisible(true);
}
static class ImageComponent extends JComponent{
static int[] x=new int[100];
static ArrayList al=new ArrayList();
public void openLine(String line_id){
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con=DriverManager.getConnection("jdbc:odbc:image");
Statement pstm=con.createStatement();
ResultSet rs=pstm.executeQuery("select * from Line where ID= '"+line_id+"'");
while(rs.next()){
x[0]=rs.getInt(3);
x[1]=rs.getInt(4);
x[2]=rs.getInt(5);
x[3]=rs.getInt(6);
al.add(x);
}
repaint();
} catch (Exception ex) {
System.out.println("Exception : "+ex);
}
}
public Graphics2D gd;
Line2D[] line=new Line2D[100];
protected void paintComponent(Graphics g) {
super.paintComponent(g);
gd=(Graphics2D)g;
gd.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
for(int i=0;i<al.size();i++){
line[i]=new Line2D.Double(x[0], x[1],x[2],x[3]);
gd.draw(line[i]);
}
}
}
}

Here is one approach that uses a BufferedImage as a rendering surface.
The OP in that question was asking about an applet, but I displayed the image in an option pane. It is just as well suited to display in a frame etc. without any confusion over whether to override paint(Graphics) or paintComponent(Graphics). ;)

You can use the Graphics object and override the paint() method like so:
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setPaint(Color.gray);
int x = 5;
int y = 7;
g2.draw(new Line2D.Double(x, y, 200, 200));
g2.drawString("Line2D", x, 250);
}
Taken from here

You shouldn't directly on a JFrame. All rendering in the main body of JFrame is done in the contentpane. Menu content is done in the JMenuBar

One issue is that you create a new ImageComponent every time the button is clicked but it is not added to your frame.
Another one is that you fill in an arraylist (al) but don't use it to actually draw your line.
This works for me with dummy values for x[0], x[1], x[2], x[3]:
static JFrame test;
static ImageComponent image = new ImageComponent(); //declared as a class member
public static void main(String ar[]) {
test = new JFrame("Test");
JButton openLine = new JButton(new AbstractAction("Open Line") {
public void actionPerformed(ActionEvent e) {
String lineId = JOptionPane.showInputDialog("Enter Line id");
image.openLine(lineId);
}
});
test.add(openLine, BorderLayout.NORTH);
test.add(image); //ADD THE IMAGE TO THE FRAME
image.setVisible(true);
test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
test.setSize(600, 600);
test.setVisible(true);
}

Related

Trouble calling a JAVA file from a JAVA File

I'm fairly new to java and am having trouble calling a mini tennis game I coded, following a tutorial, into another java file. Essentially a button in the Main File will call my game and display it in another JFrame. I haven't been able to get my game frame to open and I know it has something to do with the layout of my code for the game but I have tried rearranging and I haven't been able to call it because the main function throws an interrupted exception because there is a thread in there that keeps the game looping. What would I put in my main program to call it and how can I modify my mini tennis game to be able to be called? Basically, how can I modify the code below to be able to be called using a Game2 game = new Game2(); in another program? Or is there another method?
#SuppressWarnings("serial")
public class Game2 extends JPanel {
Ball ball = new Ball(this);
Racquet racquet = new Racquet(this);
int speed = 1;
private int getScore() {
return speed - 1;
}
public Game2() {
addKeyListener(new KeyListener() {
#Override
public void keyTyped(KeyEvent e) {
}
#Override
public void keyReleased(KeyEvent e) {
racquet.keyReleased(e);
}
#Override
public void keyPressed(KeyEvent e) {
racquet.keyPressed(e);
}
});
setFocusable(true);
Sound.BACK.loop();
}
private void move() {
ball.move();
racquet.move();
}
#Override
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
ball.paint(g2d);
racquet.paint(g2d);
g2d.setColor(Color.GREEN);
g2d.setFont(new Font("Verdana", Font.BOLD, 30));
g2d.drawString(String.valueOf(getScore()), 10, 30);
}
public void gameOver() {
Sound.BACK.stop();
Sound.GAMEOVER.play();
JOptionPane.showMessageDialog(this,
"You caught it this many times " + getScore(),
"Game Over",
JOptionPane.YES_NO_OPTION);
System.exit(ABORT);
}
public static void main(String[] args) throws InterruptedException {
JFrame frame = new JFrame("Catch the Snowball");
Game2 game = new Game2();
frame.add(game);
frame.setSize(300, 400);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
while (true) {
game.move();
game.repaint();
Thread.sleep(10);
}
}
}
I am not sure if i understand you correctly, but if you want to access Game2 game = new Game2(); from another class you can create static object game.
public class Game2 extends JPanel {
public static Game2 game;
...
Then you need to initialize it.
public static void main(String[] args) throws InterruptedException {
JFrame frame = new JFrame("Catch the Snowball");
game = new Game2();
and then you can access it by
Game2.game.something();

JPanel flashing

In a Java application im making i want to update my view and redraw some targets with the positions they have.
My GameView render function and constructor:
//Constructor
public GameView(){
frame = new JFrame("Hunter");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
drawing = new MyDrawing();
drawing.setDoubleBuffered(true);;
drawing.setIgnoreRepaint(true);
frame.getContentPane().add(BorderLayout.CENTER,drawing);
frame.setResizable(false);
frame.setSize(800,600);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
//Render method where i want to draw all the object. (called form another class)
public void Render(ArrayList<Target> targets){
//drawing is a MyDrawing object see next code.
// i clear the jpanel with a white background
drawing.drawBackground();
// Loop al targets and paint them
for (Target target : targets) {
drawing.paintComponent(target.getX(), target.getY(), target.getSize());
}
}
The MyDrawing class.
public class MyDrawing extends JPanel {
//Paint a target
public void paintComponent( int x, int y, int size){
Graphics g = getGraphics();
g.setColor(Color.black);
g.fillOval(x, y, size, size);
}
public void drawBackground(){
Graphics g = getGraphics();
g.setColor(Color.white);
g.fillRect(0, 0, this.getWidth(),this.getHeight());
}
}
Render in my GameView is called in a loop from my GameController;
public void Run(){
while(notClosed){
Render();
}
try {
Thread.sleep(1000/100);
} catch (Exception e) {
// TODO: handle exception
}
}
}
public void Render(){
myView.Render(myGame.getTargets());
}
Eveything I want is drawn on the screen but i see some flashes. Especialy on the left side of the jpanel the flashes are very visible. Also once in every x? secons the whole screen flashes. I call the setDubbelBuffer(true)in the constructor of gameview.

Java JPanel getGraphics()

Since Java only supports single inheritance, I desire to paint directly on an instance of a JPanel that is a member of the class Panel. I grab an instance of Graphics from the member and then paint whatever I desire onto it.
How can I not inherit from JComponent or JPanel and still utilize getGraphics() for painting on this without overriding public void paintComponent(Graphics g)?
private class Panel {
private JPanel panel;
private Graphics g;
public Panel() {
panel = new JPanel();
}
public void draw() {
g = panel.getGraphics();
g.setColor(Color.CYAN);
g.draw(Some Component);
panel.repaint();
}
}
The panel is added to a JFrame that is made visible prior to calling panel.draw(). This approach is not working for me and, although I already know how to paint custom components by inheriting from JPanel and overriding public void paintComponent(Graphics g), I did not want to inherit from JPanel.
Here are some very simple examples which show how to paint outside paintComponent.
The drawing actually happens on a java.awt.image.BufferedImage, and we can do that anywhere, as long as we're on the Event Dispatch Thread. (For discussion of multithreading with Swing, see here and here.)
Then, I'm overriding paintComponent, but only to paint the image on to the panel. (I also paint a little swatch in the corner.)
This way the drawing is actually permanent, and Swing is able to repaint the panel if it needs to without causing a problem for us. We could also do something like save the image to a file easily, if we wanted to.
import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
/**
* Holding left-click draws, and
* right-clicking cycles the color.
*/
class PaintAnyTime {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new PaintAnyTime();
}
});
}
Color[] colors = {Color.red, Color.blue, Color.black};
int currentColor = 0;
BufferedImage img = new BufferedImage(256, 256, BufferedImage.TYPE_INT_ARGB);
Graphics2D imgG2 = img.createGraphics();
JFrame frame = new JFrame("Paint Any Time");
JPanel panel = new JPanel() {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// Creating a copy of the Graphics
// so any reconfiguration we do on
// it doesn't interfere with what
// Swing is doing.
Graphics2D g2 = (Graphics2D) g.create();
// Drawing the image.
int w = img.getWidth();
int h = img.getHeight();
g2.drawImage(img, 0, 0, w, h, null);
// Drawing a swatch.
Color color = colors[currentColor];
g2.setColor(color);
g2.fillRect(0, 0, 16, 16);
g2.setColor(Color.black);
g2.drawRect(-1, -1, 17, 17);
// At the end, we dispose the
// Graphics copy we've created
g2.dispose();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(img.getWidth(), img.getHeight());
}
};
MouseAdapter drawer = new MouseAdapter() {
boolean rButtonDown;
Point prev;
#Override
public void mousePressed(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
prev = e.getPoint();
}
if (SwingUtilities.isRightMouseButton(e) && !rButtonDown) {
// (This just behaves a little better
// than using the mouseClicked event.)
rButtonDown = true;
currentColor = (currentColor + 1) % colors.length;
panel.repaint();
}
}
#Override
public void mouseDragged(MouseEvent e) {
if (prev != null) {
Point next = e.getPoint();
Color color = colors[currentColor];
// We can safely paint to the
// image any time we want to.
imgG2.setColor(color);
imgG2.drawLine(prev.x, prev.y, next.x, next.y);
// We just need to repaint the
// panel to make sure the
// changes are visible
// immediately.
panel.repaint();
prev = next;
}
}
#Override
public void mouseReleased(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
prev = null;
}
if (SwingUtilities.isRightMouseButton(e)) {
rButtonDown = false;
}
}
};
PaintAnyTime() {
// RenderingHints let you specify
// options such as antialiasing.
imgG2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
imgG2.setStroke(new BasicStroke(3));
//
panel.setBackground(Color.white);
panel.addMouseListener(drawer);
panel.addMouseMotionListener(drawer);
Cursor cursor =
Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR);
panel.setCursor(cursor);
frame.setContentPane(panel);
frame.pack();
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
It's also possible to set up a JLabel with an ImageIcon, although personally I don't like this method. I don't think JLabel and ImageIcon are required by their specifications to see changes we make to the image after we've passed it to the constructors.
This way also doesn't let us do stuff like painting the swatch. (For a slightly more complicated paint program, on the level of e.g. MSPaint, we'd want to have a way to select an area and draw a bounding box around it. That's another place we'd want to be able to paint directly on the panel, in addition to drawing to the image.)
import javax.swing.*;
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
/**
* Holding left-click draws, and
* right-clicking cycles the color.
*/
class PaintAnyTime {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new PaintAnyTime();
}
});
}
Color[] colors = {Color.red, Color.blue, Color.black};
int currentColor = 0;
BufferedImage img = new BufferedImage(256, 256, BufferedImage.TYPE_INT_ARGB);
Graphics2D imgG2 = img.createGraphics();
JFrame frame = new JFrame("Paint Any Time");
JLabel label = new JLabel(new ImageIcon(img));
MouseAdapter drawer = new MouseAdapter() {
boolean rButtonDown;
Point prev;
#Override
public void mousePressed(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
prev = e.getPoint();
}
if (SwingUtilities.isRightMouseButton(e) && !rButtonDown) {
// (This just behaves a little better
// than using the mouseClicked event.)
rButtonDown = true;
currentColor = (currentColor + 1) % colors.length;
label.repaint();
}
}
#Override
public void mouseDragged(MouseEvent e) {
if (prev != null) {
Point next = e.getPoint();
Color color = colors[currentColor];
// We can safely paint to the
// image any time we want to.
imgG2.setColor(color);
imgG2.drawLine(prev.x, prev.y, next.x, next.y);
// We just need to repaint the
// label to make sure the
// changes are visible
// immediately.
label.repaint();
prev = next;
}
}
#Override
public void mouseReleased(MouseEvent e) {
if (SwingUtilities.isLeftMouseButton(e)) {
prev = null;
}
if (SwingUtilities.isRightMouseButton(e)) {
rButtonDown = false;
}
}
};
PaintAnyTime() {
// RenderingHints let you specify
// options such as antialiasing.
imgG2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
imgG2.setStroke(new BasicStroke(3));
//
label.setPreferredSize(new Dimension(img.getWidth(), img.getHeight()));
label.setBackground(Color.white);
label.setOpaque(true);
label.addMouseListener(drawer);
label.addMouseMotionListener(drawer);
Cursor cursor =
Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR);
label.setCursor(cursor);
frame.add(label, BorderLayout.CENTER);
frame.pack();
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
class SomeComponent extends JComponent {
private Graphics2D g2d;
public void paintComponent(Graphics g) {
g2d = (Graphics2D) g.create();
g2d.setColor(Color.BLACK);
g2d.scale(scale, scale);
g2d.drawOval(0, 0, importance, importance);
}
public Graphics2D getG2d() {
return g2d;
}
public void setG2d(Graphics2D g2d) {
this.g2d = g2d;
}
}
then you can do the following
get the SomeComponent instance in the panel and modify it
Graphics2D x= v.getPanel().get(i).getG2d;
x.setColor(Color.BLUE);
v.getPanel().get(i).setG2d(x);
v.getPanel().repaint();
v.getPanel().revalidate();
V is a class that extends JFrame and contains the panel in it AND
i is instance of SomeComponent

Print button occurs on actual hardcopy in java

I am printing various elements such as text and images using the Panels and components it is generating pages for printing and print is also coming but the hard print also has the print button on physical paper. I to remove the print button from the page. here is the code
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.awt.print.*;
public class Printing extends JFrame
implements ActionListener {
public static void main(String[] args)
{
// intialise
}
public Printing(String Firstname,String LastName,String contactid)
{
super("Print badge");
WindowUtilities.setNativeLookAndFeel();
addWindowListener(new ExitListener());
Container content = getContentPane();
JButton printButton = new JButton("Print");
printButton.addActionListener(this);
JPanel buttonPanel = new JPanel();
buttonPanel.setBackground(Color.BLACK);
buttonPanel.add(printButton);
content.add(buttonPanel, BorderLayout.SOUTH);
DrawingPanel drawingPanel = new DrawingPanel(Firstname,LastName,contactid);
content.add(drawingPanel, BorderLayout.CENTER);
pack();
setVisible(true);
}
public void actionPerformed(ActionEvent event)
{
//call for printing
}
}
and code for actual printing panel
public class DrawingPanel extends JPanel
{
private int fontSize1 = 32;
private Image img1=null;
public DrawingPanel(String n1,String n2,String n3)
{
String path="D:"+"\\25175.jpg";
setBackground(Color.white);
Font font = new Font("Serif", Font.PLAIN, 32);
setFont(font);
img1=new ImageIcon(path).getImage();
setPreferredSize(new Dimension(400, 400));
}
public void paintComponent(Graphics g)
{
Graphics2D g2d = (Graphics2D)g;
g2d.translate(x, y);
g2d.setPaint(Color.lightGray);
AffineTransform origTransform = g2d.getTransform();
g2d.shear(-0.95, 0);
g2d.scale(1, 3);
g2d.setTransform(origTransform);
g2d.setPaint(Color.BLUE);
g2d.drawString(string,25 , 50);
g2d.drawString(string, 125,100);
g.drawImage(img1, 280, 190, null);
}
}
The print method setup is here
import java.awt.*;
import javax.swing.*;
import java.awt.print.*;
public class PrintUtilities implements Printable {
private Component componentToBePrinted;
public static void printComponent(Component c) {
new PrintUtilities(c).print();
}
public PrintUtilities(Component componentToBePrinted) {
this.componentToBePrinted = componentToBePrinted;
}
public void print() {
PrinterJob printJob = PrinterJob.getPrinterJob();
printJob.setPrintable(this);
if (printJob.printDialog())
try {
printJob.print();
} catch(PrinterException e) {
System.out.println("Error printing: " + e);
}
}
public int print(Graphics g, PageFormat pageFormat, int pageIndex) {
if (pageIndex > 0) {
return(NO_SUCH_PAGE);
} else {
Graphics2D g2d = (Graphics2D)g;
g2d.translate(pageFormat.getImageableX(), pageFormat.getImageableY());
disableDoubleBuffering(componentToBePrinted);
componentToBePrinted.paint(g2d);
enableDoubleBuffering(componentToBePrinted);
return(PAGE_EXISTS);
}
}
public static void disableDoubleBuffering(Component c) {
RepaintManager currentManager = RepaintManager.currentManager(c);
currentManager.setDoubleBufferingEnabled(false);
}
public static void enableDoubleBuffering(Component c) {
RepaintManager currentManager = RepaintManager.currentManager(c);
currentManager.setDoubleBufferingEnabled(true);
}
}
by this call PrintUtilities.printComponent(this) in button action listener
This would seem to be your problem.
This will, technically, print the contents of the entire frame, you only need to print the DrawingPanel.
This is going to require you to make some minor changes to your code so you access the instance of the DrawingPanel from your actionPerformed method...
private DrawingPanel drawingPanel;
public Printing(String Firstname,String LastName,String contactid)
{
super("Print badge");
//...
drawingPanel = new DrawingPanel(Firstname,LastName,contactid);
//...
}
This should no allow you to do something like...
PrintUtilities.printComponent(drawingPanel);
Instead...
You can
define custom clip for the print Graphics to exclude the print button area
OR 2. just hide the button
OR 3. override the button's paintComponent() method where check isPrint flag (if it's false call super it true do nothing).

paintComponent does not work if its called by the recursive function?

I want to see all the Points one after another but I see only able to see 1
point. What shold I change to see all the Points ?
In the System.out you can see 10 times "set" and then 2 times
"paintComponent". what should I change that after each time set is
called it change the "paintComponente" ?
==================================================================================
public class exampe extends JPanel
{
int x;
int y;
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.fillOval(x-2,y-2,4,4);
System.out.println("paintComponent");
}
public void set(int X, int Y)
{
x = X;
y = Y;
System.out.println("set");
super.repaint();
}
public static void main(String args[])
{
int e=1;
JFrame frame = new JFrame("TEST");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
exampe ex= new exampe();
JScrollPane scroll = new JScrollPane(ex);
frame.getContentPane().add(scroll);
frame.setSize(400, 300);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
for(int i=0; i< 10; ++i)
ex.set(e+i,e+i);
}
}
*SIMPLE EXPLANATION AS TO WHY YOU COULD ONLY SEE THE LAST UPDATE : *
A quote taken from Filthy Rich Clients by Chet Haase and Romain Guy
It is important to note that repaint requests get “coalesced,” or combined.
So, for example, if you request a repaint and there is already one on the
queue that has not yet been serviced, then the second request is ignored
because your request for a repaint will already be fulfilled by the earlier
request. This behavior is particularly helpful in situations where many
repaint requests are being generated, perhaps by very different situations
and components, and Swing should avoid processing redundant requests and
wasting effort.
Try your hands on this, and ask what is not clear to you :
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class PointsExample
{
private CustomPanel contentPane;
private Timer timer;
private int x = 1;
private int y = 1;
private ActionListener timerAction = new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
contentPane.set(x, y);
x++;
y++;
if (x == 450)
timer.stop();
}
};
/*
* This is just JFrame, that we be
* using as the Base for our Application.
* Though here we are calling our
* JPanel (CustomPanel), whose
* paintComponent(...) method, we had
* override.
*/
private void createAndDisplayGUI()
{
JFrame frame = new JFrame("Locate Mouse Position");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
contentPane = new CustomPanel();
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
timer = new Timer(100, timerAction);
timer.start();
}
public static void main(String\u005B\u005D args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new PointsExample().createAndDisplayGUI();
}
});
}
}
class CustomPanel extends JComponent
{
private int x;
private int y;
public void set(int a, int b)
{
x = a;
y = b;
repaint();
}
#Override
public Dimension getPreferredSize()
{
return (new Dimension(500, 500));
}
#Override
public void paintComponent(Graphics g)
{
g.clearRect(0, 0, getWidth(), getHeight());
Graphics2D g2 =(Graphics2D) g;
g2.fillOval(x, y, 4, 4);
}
}
Here is the code, that will allow you to have a look at your points while iterating inside a for loop, though this approach is highly discouraged, for many cons associated with it. Though try your hands on this instead of calling repaint() call paintImmediately(int ...) or paintImmediately(Rectangle rect)
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class PointsExample
{
private CustomPanel contentPane;
private Timer timer;
private int x = 1;
private int y = 1;
/*
* This is just JFrame, that we be
* using as the Base for our Application.
* Though here we are calling our
* JPanel (CustomPanel), whose
* paintComponent(...) method, we had
* override.
*/
private void createAndDisplayGUI()
{
JFrame frame = new JFrame("Locate Mouse Position");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
contentPane = new CustomPanel();
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
for (int i = 0; i < 500; i++)
{
contentPane.set(x, y);
x++;
y++;
if (x == 450)
break;
}
}
public static void main(String\u005B\u005D args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new PointsExample().createAndDisplayGUI();
}
});
}
}
class CustomPanel extends JComponent
{
private int x;
private int y;
public void set(int a, int b)
{
x = a;
y = b;
paintImmediately(0, 0, getWidth(), getHeight());
}
#Override
public Dimension getPreferredSize()
{
return (new Dimension(500, 500));
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.fillOval(x, y, 4, 4);
}
}
1: first line of paintComponent() should be your super.paintComponent()
2: why are you calling super.repaint(), make it simply repaint()
Your Drow should be like this.
public class drow extends JPanel {
...........
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 =(Graphics2D) g;
}
public void set_list(LinkedList <point> p){
Points =p;
repaint();
}
try with this.
i hope this is simply a structure, your paintComponent() isn't drawing anything.
EDIT
public void set_list(LinkedList <point> p){
Points =p;
System.out.println("set_ist");// 1:First this line will be displayed then..
repaint();//2: Then this is called, which in turn calls your `paintComponent()`
}
Now when your paintComponent() is called it has
system.out.println("paintComponent");
//3: so now this will be displayed.
Where is the problem here?
EDIT- SWING TIMER
Your code was ok, but the function processing is way faster than GUI updation, thats why you were unable to see the changes in front of you. The way you were doing, of calling thread.sleep() between function calls to slow down it's call, was not a good approach. For any timing thing's in swing, use swing timer, i changed your code for swing timer.
Using Swing Timer:
public class exampe extends JPanel implements ActionListener {
int x;
int y;
int temp = 0;
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.fillOval(x - 2, y - 2, 4, 4);
}
public void set(int X, int Y) {
x = X;
y = Y;
}
public static void main(String args[]) {
JFrame frame = new JFrame("TEST");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
exampe ex = new exampe();
JScrollPane scroll = new JScrollPane(ex);
frame.getContentPane().add(scroll);
frame.setSize(400, 300);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
Timer PointTimer = new Timer(1000, ex);
PointTimer.setInitialDelay(1000);
PointTimer.start();
System.out.println("started");
}
#Override
public void actionPerformed(ActionEvent e) {
// set(rand.nextInt(350), rand.nextInt(350));
set(temp+10,temp+10);
temp=temp+2;
repaint();
}
}

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