Develop Reference

How do I properly implement a mouselistener to my Jcomponent?

I have a project where I need to create a GUI in Java that creates a circle on mouse-click and and continues to make trailing circles as the mouse is dragged through the frame. I've been given reference to multiple threads on here but none have seemed to help me do what I need to do. So far I've got a static circle added to my JFrame, but I want to make the multiple circles show on a JPanel in that frame. I'm stuck after trying many different angles. As of now I just need to be able to click once and create a circle.
public class Theremin extends JFrame implements ActionListener, MouseListener{
private JPanel windowArea;
private int x, y;
private static final long serialVersionUID = 1L;
public Theremin() {
}
public static void main(String[] args) {
Theremin Frame = new Theremin();
Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MyPanel panel = new MyPanel();
panel.setLayout(null);
Frame.add(panel);
Frame.pack();
Frame.setLocationRelativeTo(null);
Frame.setVisible(true);
}
private static class MyPanel extends JPanel {
public void paint(Graphics g) {
Graphics2D gObj = (Graphics2D)g;
Shape disk = new Ellipse2D.Double(10, 10, 100, 100);
gObj.setColor(new Color(255, 0, 0, 120));
gObj.fill(disk);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(700, 600);
}
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseClicked(MouseEvent e) {
x = e.getX();
y = e.getY();
repaint();
}
#Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
}

Here's a GUI that I put together.
Each mouse click creates a circle.
When I create a Swing GUI, or any Java application, I use the model / view / controller (MVC) pattern. This pattern allows me to separate my concerns and focus on one part of the application at a time.
For a Swing GUI, the MVC pattern means:
The view reads from the model.
The view does not update the model.
The controller updates the model and repaints / revalidates the view.
The model consists of two classes, Circles and Circle. The Circle class defines a circle with a Point center, int radius, and a Color color. Because Circle is a class, I can define as many instances (circles) as I want.
The Circles class holds a List of Circle instances.
The view consists of a JFrame and a drawing JPanel. The paintComponent method of the drawing JPanel paints circles. Period. We create the circles in the controller class.
The controller class CirclesListener creates the circles and repaints the drawing JPanel. All of the circles are redrawn each and every time the drawing JPanel is repainted.
An instance of the JFrame class and the application model class is passed to the controller CirclesListener class. This allows the class to create a new circle and repaint the drawing JPanel.
Here's the complete runnable code.
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class MouseClickCircleGUI implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new MouseClickCircleGUI());
}
private Circles circles;
private DrawingPanel drawingPanel;
public MouseClickCircleGUI() {
this.circles = new Circles();
}
#Override
public void run() {
JFrame frame = new JFrame("Circles");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
drawingPanel = new DrawingPanel(this, circles);
frame.add(drawingPanel, BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public void repaint() {
drawingPanel.repaint();
}
public class DrawingPanel extends JPanel {
private static final long serialVersionUID = 1L;
private final Circles circles;
public DrawingPanel(MouseClickCircleGUI frame, Circles circles) {
this.circles = circles;
setBackground(Color.WHITE);
setPreferredSize(new Dimension(500, 500));
addMouseListener(new CirclesListener(frame, circles));
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setStroke(new BasicStroke(3f));
for (Circle circle : circles.getCircles()) {
Point p = circle.getCenter();
int radius = circle.getRadius();
g2.setColor(circle.getColor());
g2.drawOval(p.x - radius, p.y - radius,
2 * radius, 2 * radius);
}
}
}
public class CirclesListener extends MouseAdapter {
private final Circles circles;
private final MouseClickCircleGUI frame;
public CirclesListener(MouseClickCircleGUI frame, Circles circles) {
this.frame = frame;
this.circles = circles;
}
#Override
public void mouseReleased(MouseEvent event) {
circles.addCircle(new Circle(event.getPoint(), 30, Color.BLACK));
frame.repaint();
}
}
public class Circles {
private final List<Circle> circles;
public Circles() {
this.circles = new ArrayList<>();
}
public void addCircle(Circle circle) {
this.circles.add(circle);
}
public List<Circle> getCircles() {
return circles;
}
}
public class Circle {
private final int radius;
private final Color color;
private final Point center;
public Circle(Point center, int radius, Color color) {
this.center = center;
this.radius = radius;
this.color = color;
}
public int getRadius() {
return radius;
}
public Point getCenter() {
return center;
}
public Color getColor() {
return color;
}
}
}

The idea here is to:
capture point
add it to list
repaint component
Here is how I have done it, this is a sample code.
package com.company;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Ellipse2D;
import java.util.ArrayList;
import java.util.List;
public class Main {
public static void main(String[] args) {
Theremin frame = new Theremin();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
MyPanel panel = new MyPanel();
panel.initListeners();
panel.setLayout(null);
frame.add(panel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.addWindowListener(new WindowListener() {
#Override
public void windowOpened(WindowEvent e) {
}
#Override
public void windowClosing(WindowEvent e) {
panel.releaseListener();
}
#Override
public void windowClosed(WindowEvent e) {
}
#Override
public void windowIconified(WindowEvent e) {
}
#Override
public void windowDeiconified(WindowEvent e) {
}
#Override
public void windowActivated(WindowEvent e) {
}
#Override
public void windowDeactivated(WindowEvent e) {
}
});
}
}
class MyPanel extends JPanel implements MouseListener, MouseMotionListener {
private Graphics graphics;
private List<CircleData> shapeList = new ArrayList<>();
private Graphics2D gObj;
public MyPanel() {
}
#Override
public void paint(Graphics g) {
this.graphics = g;
gObj = (Graphics2D) g;
System.out.println("called paint with times: " + times++);
for (CircleData circleData : shapeList) {
Rectangle rectangle = circleData.rectangle;
Color color = circleData.color;
Shape disk = new Ellipse2D.Double(rectangle.x, rectangle.y, rectangle.width, rectangle.height);
gObj.setColor(color);
gObj.fill(disk);
}
}
Color randomColor() {
int red = (int) (Math.random() * 256);
int green = (int) (Math.random() * 256);
int blue = (int) (Math.random() * 256);
return new Color(red, green, blue);
}
static int times = 0;
#Override
public Dimension getPreferredSize() {
return new Dimension(700, 600);
}
public void initListeners() {
System.out.println("added default listeners");
addMouseListener(this);
addMouseMotionListener(this);
}
public void releaseListener() {
System.out.println("removed default listeners");
removeMouseListener(this);
removeMouseMotionListener(this);
}
#Override
public void mouseClicked(MouseEvent e) {
float x = e.getX();
float y = e.getY();
String cordinates = String.format("(%f, %f)", x, y);
System.out.println("Mouse Clicked # " + cordinates);
shapeList.add(new CircleData(new Rectangle((int) x, (int) y, 50, 50), randomColor()));
repaint();
}
#Override
public void mousePressed(MouseEvent e) {
}
#Override
public void mouseReleased(MouseEvent e) {
}
#Override
public void mouseEntered(MouseEvent e) {
}
#Override
public void mouseExited(MouseEvent e) {
}
#Override
public void mouseDragged(MouseEvent e) {
float x = e.getX();
float y = e.getY();
String cordinates = String.format("(%f, %f)", x, y);
System.out.println("Mouse Dragged # " + cordinates);
System.out.println("Mouse Dragged # " + shapeList.size());
shapeList.add(new CircleData(new Rectangle((int) x, (int) y, 50, 50), randomColor()));
repaint();
}
#Override
public void mouseMoved(MouseEvent e) {
}
}
class CircleData {
Rectangle rectangle;
Color color;
public CircleData(Rectangle rectangle, Color color) {
this.rectangle = rectangle;
this.color = color;
}
}
class Theremin extends JFrame {
private static final long serialVersionUID = 1L;
public Theremin() {
}
}

Action is not getting triggered when using Event handlers- KeyListener

So I am new to event handlers, and I wanted to create a program where I made a Purple panel inside a frame and if the user clicks the mouse button in the area of the panel and then types % with their keyboard, I want the panel to draw a line segment in the area of the panel. This is just testing the event handlers. Right now, I am trying it but it does not work. All help will be appreciated. After I get the hand of this, I want to try out the repaint() method, where if someone does the same actions as before, I wanted to check the background of the Panel. If you can help me with both, that'd be awesome but it is not a priority. Thank you.
import java.awt.Graphics; // for classes Graphics, Color, Font, Image
import java.awt.Color;
import java.awt.Font;
import java.awt.event.KeyEvent; // for classes KeyListener, MouseListener
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JFrame; // for classes JFrame, JPanel, JLabel
import javax.swing.JPanel;
public class GardenGrows
{
public GardenGrows()
{
}
public static void main(String[] args)
{
GardenGrows gg = new GardenGrows();
gg.runIt();
}
// makes the frame and handles all properties of the frame
// also instantiates the Garden.java object
public void runIt()
{
JFrame frame = new JFrame ("Garden");
frame.setDefaultCloseOperation( frame.EXIT_ON_CLOSE );
frame.setLayout(null);
frame.setBackground(Color.GRAY);
frame.setSize( 1200,700);
frame.setLocation( 50, 10);
frame.setResizable(true);
frame.setVisible(true);
Garden gar = new Garden();
frame.getContentPane().add(gar);
}
}
class Garden extends JPanel implements KeyListener, MouseListener
{
private boolean mouseClicked;
private boolean keyClicked;
private int xpos;
private int ypos;
public Garden()
{
mouseClicked = false;
keyClicked = false;
addKeyListener(this);
addMouseListener(this);
setBackground(Color.PINK);
setLocation(50,50);
setSize(1000,500);
}
public void mousePressed(MouseEvent evt)
{
int x = evt.getX();
int y = evt.getY();
if(x>=50 || x<=1050 && y<=50 || y>=550)
{
mouseClicked = true;
}
}
public void mouseClicked(MouseEvent evt){}
public void mouseReleased(MouseEvent evt){}
public void mouseEntered(MouseEvent evt){}
public void mouseExited(MouseEvent evt){}
public void keyReleased(KeyEvent evt){}
public void keyPressed(KeyEvent evt){}
public void keyTyped(KeyEvent evt)
{
int letter = evt.getKeyCode();
if (letter == 13)
{
keyClicked =true;
}
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
if(keyClicked && mouseClicked)
g.drawLine(50,0,110,120);
}
}

Making a key listener work in a JPanel, will not be so simple, because it is not focusable. (Think about a JTextField, when you write text on it, it is focused). So, in order to make this work you will have to use KeyBindings. In practice, remove the KeyListener implementation from your JPanel, and use KeyBindings.
public class GardenGrows {
public GardenGrows() {
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
// All swing applications must run on EDT Thread
GardenGrows gg = new GardenGrows();
gg.runIt();
});
}
// makes the frame and handles all properties of the frame
// also instantiates the Garden.java object
public void runIt() {
JFrame frame = new JFrame("Garden");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(null);
frame.setBackground(Color.GRAY);
frame.setSize(1200, 700);
frame.setLocation(50, 10);
frame.setResizable(true);
frame.setVisible(true);
Garden gar = new Garden();
frame.getContentPane().add(gar);
}
}
class Garden extends JPanel implements MouseListener {
private boolean mouseClicked;
private boolean keyClicked;
private int xpos;
private int ypos;
public Garden() {
mouseClicked = false;
keyClicked = false;
addMouseListener(this);
setBackground(Color.PINK);
setLocation(50, 50);
setSize(1000, 500);
getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_5, KeyEvent.SHIFT_MASK),
"percentageClicked");
getActionMap().put("percentageClicked", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
keyClicked = true;
repaint(); // Try to draw the line
}
});
}
public void mousePressed(MouseEvent evt) {
int x = evt.getX();
int y = evt.getY();
if (x >= 50 || x <= 1050 && y <= 50 || y >= 550) {
mouseClicked = true;
repaint(); // Try to draw the line
}
}
public void mouseClicked(MouseEvent evt) {
}
public void mouseReleased(MouseEvent evt) {
}
public void mouseEntered(MouseEvent evt) {
}
public void mouseExited(MouseEvent evt) {
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (keyClicked && mouseClicked)
g.drawLine(50, 0, 110, 120);
}
}

label that shows Coordinates of mouse

At university we started Java programming and got the task to write a program that draws a vertical and a horizontal line at the location where the mouse currently is. Also we should add a Label that shows the coordinates of the mouse. I got the drawing thing working but when I try to add a label, it won't show up? I started with a test-label, but even that isn't shown inside the frame. Can someone help me?
public class Coordinates extends JPanel implements MouseListener, MouseMotionListener {
private Point currentPoint = new Point(-50, -50);
public Coordinates(){
addMouseListener(this);
addMouseMotionListener(this);
}
public void paint(Graphics g) {
super.paint(g);
g.setColor(Color.blue);
g.drawLine(currentPoint.x, currentPoint.y+1000, currentPoint.x, currentPoint.y-1000);
g.drawLine(currentPoint.x+1000, currentPoint.y, currentPoint.x-1000, currentPoint.y);
}
public void mousePressed(MouseEvent e){
currentPoint = e.getPoint();
repaint();
};
static JLabel label = new JLabel();
public static void main(String[] args) {
JFrame frame = new JFrame("Koordinaten");
frame.setSize(600, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.add(label);
JComponent newContentPane = new Coordinaten();
newContentPane.setOpaque(true);
frame.setContentPane(newContentPane);
}
public void mouseClicked(MouseEvent e) {
// TODO Auto-generated method stub
}
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
public void mouseDragged(MouseEvent e) {
// TODO Auto-generated method stub
}
public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub
label.setText(currentPoint.toString());
currentPoint = e.getPoint();
repaint();
}
}

Do all your painting within the JPanel's paintComponent method not the paint method, and be sure to call the super's paintComponent method within your override, usually at the start of the override method.
You need to add a JLabel to your JPanel to have it display anything. Your code does not do this. And then in the MouseMotionListener, set the JLabel's text with the mouse coordinates.
For example:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class DrawPanel extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = PREF_W;
private JLabel locationLabel = new JLabel();
public DrawPanel() {
add(locationLabel);
addMouseMotionListener(new MyMouseAdapter());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g); // this allows JPanel to do housekeeping painting first
// do drawing here!
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class MyMouseAdapter extends MouseAdapter {
#Override
public void mouseMoved(MouseEvent e) {
// get Point location and turn into a String
String location = String.format("[%d, %d]", e.getX(), e.getY());
// set the label's text with this String
locationLabel.setText(location);
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("DrawPanel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new DrawPanel());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
With the cross-hairs:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class DrawPanel extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = PREF_W;
private JLabel locationLabel = new JLabel();
private int mouseX = 0;
private int mouseY = 0;
public DrawPanel() {
add(locationLabel);
addMouseMotionListener(new MyMouseAdapter());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g); // this allows JPanel to do housekeeping
// painting first
// do drawing here!
g.drawLine(0, mouseY, getWidth(), mouseY);
g.drawLine(mouseX, 0, mouseX, getHeight());
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class MyMouseAdapter extends MouseAdapter {
#Override
public void mouseMoved(MouseEvent e) {
mouseX = e.getX();
mouseY = e.getY();
// get Point location and turn into a String
String location = String.format("[%d, %d]", mouseX, mouseY);
// set the label's text with this String
locationLabel.setText(location);
repaint();
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("DrawPanel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new DrawPanel());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

Basically, a JLabel is made like this, defined outside of the main method:
static JLabel label = new JLabel();
In your main method
frame.add(label);
And in your mouseMoved method you would put this:
label.setText(currentPoint.toString());

using repaint() method in this code

I am having a problem using the repaint method in the following code.Please suggest how to use repaint method so that my screen is updated for a small animation.
This is my code :
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class movingObjects extends JPanel {
Timer timer;
int x = 2, y = 2, width = 10, height = 10;
public void paintComponent(final Graphics g) { // <---- using repaint method
ActionListener taskPerformer = new ActionListener() {
public void actionPerformed(ActionEvent ae) {
g.setColor(Color.red);
g.drawOval(x, y, width, height);
g.fillOval(x, y, width, height);
x++;
y++;
width++;
height++;
}
};
new Timer(100, taskPerformer).start();
}
}
class mainClass {
mainClass() {
buildGUI();
}
public void buildGUI() {
JFrame fr = new JFrame("Moving Objects");
movingObjects obj = new movingObjects();
fr.add(obj);
fr.setVisible(true);
fr.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
fr.setSize(1300, 700);
}
public static void main(String args[]) {
new mainClass();
}
}

Don't try to delay the actual painting. The component needs to be painted when it is asked to be painted.
Instead, use your timer to modify some state in MovingObjects. In your case the state you want to change is x, y, width and height. When your timer fires, increment those values and call repaint().
Then in your paintComponents method, you would just use those values to paint the component
public void paintComponent(Graphics g) {
g.setColor(Color.red);
g.drawOval(x,y,width,height);
g.fillOval(x,y,width,height);
}
Edit
Not sure what you're having trouble with, but calling repaint() is not difficult:
ActionListener taskPerformer=new ActionListener() {
public void actionPerformed(ActionEvent ae) {
x++;
y++;
width++;
height++;
repaint();
}
};
new Timer(100,taskPerformer).start();

Problem with drawing

For now the following code is supposed to draw a circle onMouseDragged over the black Canvas.
Unfortunately it doesn't (=
Do I miss something?
Thanks in advance...
import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.applet.*;
import java.awt.Graphics.*;
public class IdrawApplet extends Applet {
int mosX;
int mosY;
Panel pGadgets;
Canvas myCanvas;
Label lRed;
TextField tfRed;
TextField tfGreen;
TextField tfBlue;
Label lGreen;
Label lBlue;
Graphics g;
public void init() {
g = getGraphics();
lRed = new Label("Red-value: ");
lBlue = new Label("Blue-value: ");
lGreen = new Label("Green-value: ");
tfRed = new TextField();
tfRed.setText("255");
tfGreen = new TextField();
tfGreen.setText("255");
tfBlue = new TextField();
tfBlue.setText("255");
pGadgets = new Panel();
pGadgets.setLayout(new GridLayout(1, 6, 5, 5));
add(pGadgets);
pGadgets.add(lRed);
pGadgets.add(tfRed);
pGadgets.add(lGreen);
pGadgets.add(tfGreen);
pGadgets.add(lBlue);
pGadgets.add(tfBlue);
myCanvas = new Canvas();
myCanvas.setBackground(new Color(0,0,0));
myCanvas.setBounds(0, 0, 600, 400);
add(myCanvas);
myCanvas.addMouseMotionListener(new MouseMotionListener() {
public void mouseMoved(MouseEvent e) {
// TODO Auto-generated method stub
}
public void mouseDragged(MouseEvent e) {
// TODO Auto-generated method stub
paint(g);
}
});
}
public void paint(Graphics g) {
g.setColor(Color.green);
g.fillOval(mosX, mosY, 30, 30);
}
}

Two things:
public void mouseDragged(MouseEvent e)
{
mosX = e.getX();
mosY = e.getY();
repaint(); //NOT paint(g);
}
//...
public void paint(Graphics g)
{
//draw on the canvas not on the component
//since the canvas gets drawn over it
Graphics g2 = myCanvas.getGraphics();
g2.setColor(Color.green);
g2.fillOval(mosX, mosY, 30, 30);
}
If you have anything more complex, you should subclass Canvas and override it's paint() method.

Try this:
public void mouseDragged(MouseEvent e)
{
mosX = e.getX();
mosY = e.getY();
repaint();
}
The problem was that you were not updating your coordinates for the mouseDragged event. Also instead of calling paint() directly, you should call repaint(). Calling repaint() will ensure your paint() is called automatically.
EDIT:
To paint on Canvas object, override paint() of the Canvas object.
myCanvas = new Canvas()
{
public void paint(Graphics g)
{
g.setColor(Color.green);
g.fillOval(mosX, mosY, 30, 30);
}
};
Now your mouseDragged method becomes :
public void mouseDragged(MouseEvent e)
{
mosX = e.getX();
mosY = e.getY();
myCanvas.repaint();
}