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Thread: Help with get and set

  1. #1
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    Default [SOLVED]Help with get and set

    Hi guys,

    Ok so I have to do a Pong type game for school.

    So far, I am doing it with a mousemotion listener. But the thing is, I have 2 classes, Raquette and Ball.

    the Raquette class contains the mousemotion listener for the paddle. The Ball gets refreshed using a thread.

    So I made a isHiT() method in my Ball class to see if the raquette and teh Ball comes in contact.

    But the problem is that the getY() keeps returning 0 even tough I am refresshing it....

    Here is the code:

     
    /*
     * To change this template, choose Tools | Templates
     * and open the template in the editor.
     */
     
    /**
     * Travail fait par Aravinthan Sivaneswaran
     * Date: 17-Nov-2011
     * Nom du projet:
     */
    import javax.swing.*;
    import java.awt.*;
    import java.awt.geom.*;
    import java.awt.event.*;
    import java.io.*;
    import java.awt.event.MouseMotionListener;
    import java.awt.event.MouseEvent;
     
    //classe démarrage
    public class main {
     
        public static void main(String[] args) {
            JFrame frame = new BounceThreadFrame();
            frame.setVisible(true);
        }
    }
     
    //classe de la fenêtre graphique
    class BounceThreadFrame extends JFrame {
     
        private JPanel canvas;
        int x = 0;
        private int addY = 0;
     
        public BounceThreadFrame() {
            setSize(400, 400);
            setResizable(false);
            setLocationRelativeTo(null);  //laisse l'OS placer la fenêtre
            setTitle("Bounce");
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     
            canvas = new JPanel();
     
            getContentPane().add(canvas, "Center");
            JButton b = new JButton("Lancer balle");
            getContentPane().add(b, "North");
     
     
            b.addActionListener(new ActionListener() {
     
                public void actionPerformed(ActionEvent evt) {
     
                    if (x == 0) {
                        Ball b = new Ball(canvas);
                        Raquette r = new Raquette(canvas);
                        b.start();  //pour exécuter la méthode run() du thread
                        r.draw();
                        r.start();
                    }
     
                    x++;
                }
            });
     
        }
    }
     
    //classe Balle hérite de Thread
    class Ball extends Thread {
     
        private JPanel box;  //panneau supportant la balle
        private static final int XSIZE = 20, YSIZE = 20;//dimensions balle
        private int x = 0, y = 0;  //position initiale balle
        private int dx = 4; //déplacement balle (horizontal)
        private int dy = 4;
        public boolean notout = true;
     
        Raquette r = new Raquette(box);
     
        public Ball(JPanel b) {
            box = b;
        }
     
        // exécution du thread (déclenché par start)
        public void run() {
            try {
                while (notout) {
                    sleep(20); //attendre 5 ms
                    move();   //déplacer balle
     
                }
            } catch (InterruptedException e) {
            }
        }
     
        //méthode déplacer balle
        public void move() {
            Graphics g = box.getGraphics();
            Dimension d = box.getSize();
            g.setXORMode(box.getBackground());//pour que les pixels retrouvent leur couleur d'origine lors du 2ème dessin (qui suit)
            g.fillOval(x, y, XSIZE, YSIZE); // on dessine la balle
     
            x += dx;  //on augmente l'abcisse pour déplace la balle horizontalement
            y += dy;
     
            if (x < 1) {
                dx = -dx;
            }
            if (y < 1) {
                dy = -dy;
            }
            if ((x + XSIZE) > d.width) {
                //.showMessageDialog(null, "La balle est sorti. Vous perdez 1 vie", "Vie perdu", JOptionPane.INFORMATION_MESSAGE);
                //notout = false;
                dx = -dx;
            }
            if ((y + YSIZE) > d.height) {
                dy = -dy;
            }
     
            //System.out.println(isHIT());
            if(isHIT()){
                dx = -dx;
                dy = -dy;
            }
     
            g.fillOval(x, y, XSIZE, YSIZE);  //on redessine
     
        }
     
        public boolean isHIT() {
            int raquettey;
     
            raquettey = r.getY();
            System.out.println(raquettey);
            if((y>raquettey && y<(raquettey+r.getYSIZE())) && (x>=box.getWidth()-r.getXSIZE()))
                return true;
            else
                return false;
        }
    } //fin classe balle
     
    //classe Balle hérite de Thread
    class Raquette extends Thread implements MouseMotionListener {
     
        private JPanel box;  //panneau supportant la balle
        private static final int XSIZE = 10, YSIZE = 50;//dimensions balle
        private int x = 385, y = 0;  //position initiale balle
        private int dx = 2; //déplacement balle (horizontal)
        private int dy = 2;
        private int addY;
     
        public Raquette(JPanel r) {
            box = r;
        }
     
        // exécution du thread (déclenché par start)
        public void run() {
            try {
                while (true) {
                    sleep(10); //attendre 5 ms
                    move();   //déplacer balle
     
     
                }
            } catch (InterruptedException e) {
            }
        }
        //méthode déplacer balle
     
        public void draw() {
            Graphics g = box.getGraphics();
            Dimension d = box.getSize();
            g.setXORMode(box.getBackground());//pour que les pixels retrouvent leur couleur d'origine lors du 2ème dessin (qui suit)
            g.fillRect(x, y, XSIZE, YSIZE); // on dessine la balle
        }
     
        //méthode déplacer balle
        public void move() {
            box.addMouseMotionListener(this);
            Graphics g = box.getGraphics();
            Dimension d = box.getSize();
            g.setXORMode(box.getBackground());//pour que les pixels retrouvent leur couleur d'origine lors du 2ème dessin (qui suit)
            g.fillRect(x, y, XSIZE, YSIZE); // on dessine la balle
     
            y = addY;
     
            if (y <= 0) {
                y = 0;
            }
            if ((y + (YSIZE)) > d.height) {
                y = d.height - YSIZE;
            }
     
            setY(y);
            g.fillRect(x, y, XSIZE, YSIZE);  //on redessine
     
        }
     
        void eventOutput(String eventDescription, MouseEvent e) {
            addY = (e.getY());
        }
     
        public void mouseMoved(MouseEvent e) {
            eventOutput("Mouse moved", e);
        }
     
        public void mouseDragged(MouseEvent e) {
            eventOutput("Mouse dragged", e);
        }
     
        public void setY(int y){
            this.y = y;
        }
     
        public int getY(){
            return this.y;
        }
     
        public int getXSIZE(){
            return this.XSIZE;
        }
     
        public int getYSIZE(){
            return this.YSIZE;
        }
    } //fin classe raquette
    Last edited by AraHabs; November 20th, 2011 at 11:46 AM. Reason: Solved


  2. #2
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    Default Re: Help with get and set

    Try debugging your code by adding printlns to show the values of variables as their values are changed.
    The output should show when the variable has been given a good value and when it has been set to zero.

  3. #3
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    Default Re: Help with get and set

    I placed a println Right after the setY() in the class Raquette and it showed the right value.
    I placed a println Before using the getY() in the class Ball and it shows 0.

  4. #4
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    Default Re: Help with get and set

    Add printlns to the constructors to show when each class is created and how many of them.

    You could use the 'this' variable in the printlns to get an id for each class.

  5. #5
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    Default Re: Help with get and set

    I added a println in teh constructors like you said.

    So it gives this:
        public void setY(int a){
            this.y = a;
            System.out.println("SET"+this.y);
        }
     
        public int getY(){
            System.out.println("GET"+this.y);
            return this.y;
        }

    The set gives me the correct value.
    But the get keeps returning 0...

  6. #6
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    Default Re: Help with get and set

    How many instances of the class were created?
    For which instance is the setY method called?
    For which instance is the getY method called?
    Add a 'this' to the printlns to see:
    System.out.println(this + " SET y="+y);
    System.out.println(this + " GET y="+y);

    Look at what is printed out.

  7. #7
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    Default Re: Help with get and set

    Ok,
    So when I have the get in my class Ball, the get returns 0.
    So to try it out, I took out the get in the class Ball and put a get right after the set.

    And it returns the right number.

    A part of the printed section:
    Thread[Thread-4,6,main] GET y=0
    Thread[Thread-5,6,main] SET y=0
    Thread[Thread-5,6,main] GET y=0
    Thread[Thread-5,6,main] SET y=4
    Thread[Thread-5,6,main] GET y=4
    Thread[Thread-4,6,main] GET y=0
    Thread[Thread-5,6,main] SET y=8
    Thread[Thread-5,6,main] GET y=8
    Thread[Thread-5,6,main] SET y=14
    Thread[Thread-5,6,main] GET y=14
    Thread[Thread-4,6,main] GET y=0
    Thread[Thread-5,6,main] SET y=17
    Thread[Thread-5,6,main] GET y=17
    Thread[Thread-5,6,main] SET y=20
    Thread[Thread-5,6,main] GET y=20
    The Thread-4 is my Ball class and the Thread 5 is in my Raquette class.
    Could the thread be intefering in this?

  8. #8
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    Default Re: Help with get and set

    You have two instances of a class. You call setY for one and change it's y value.
    When you call getY you get the y value from the other instance of the class which is never changed from 0.

    Can you change the code so there is only one class that everyone uses?

  9. #9
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    Default Re: Help with get and set

    Ok yeah, I get it.

    I will try to do it and let you know.

    EDIT:

    It works!! Thanks alot!!!

    Thanks for your help,
    Ara
    Last edited by AraHabs; November 20th, 2011 at 11:45 AM. Reason: Finished

  10. #10
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    Default Re: Help with get and set

    It should be better if you do the set and get on the same instance instead of different ones.