StackOverflow2013

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POWhy both ovals located at the same XY?
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copied!<p>I declared and built an array of two Balls instances ' m_ball[0]=new Ball(400,400,400,180);' & ' m_ball[1]=new Ball(400,400,400,0);' with different parameter values (180 and 0) but for some reason it seems that this different values get reset to 0 when the Timer start running and than both balls place on the same XY location. Can someone see why? I'm new in programming, Many Thanks... .</p> <pre><code>//This is main public class BBDemo extends JApplet{ ........... } }//endclass BBDemo public class BBPanel extends JPanel { BallInBox m_bb; // The moving ball panel ///in order to take the Timer->setAnimation from m_bb //========================================================== constructor /** Creates a panel with the controls and moving ball display. */ BBPanel() { //... Create components m_bb = new BallInBox(); // The moving ball panel ......... startButton.addActionListener(new StartAction()); ......... } }//endclass BBPanel public class BallInBox extends JPanel { private Ball m_ball[]= new Ball[2]; //... Instance variables for the animation private int m_interval = 40; // Milliseconds between updates. static Timer m_timer; // Timer fires to animate one step. static int j; private Color Pigment; //=================================================== constructor /** Set panel size and creates timer. */ public BallInBox() { ......... m_timer = new Timer(m_interval, new TimerAction()); addMouseListener(new PressBall()); m_ball[0]=new Ball(400,400,400,180); m_ball[1]=new Ball(400,400,400,0); } public void setAnimation(boolean turnOnOff) { if (turnOnOff) { m_timer.start(); j=1; // start animation by starting the timer. } else { m_timer.stop(); j=0; // stop timer } } //======================================================= paintComponent public void paintComponent(Graphics g) { super.paintComponent(g); // Paint background, border ........ g.setColor(Pigment); m_ball[0].draw(g); // Draw the ball. m_ball[1].draw(g); } class TimerAction implements ActionListener { public void actionPerformed(ActionEvent e) { m_ball[0].setBounds(getWidth(), getHeight()); m_ball[0].move(); // Move the ball. m_ball[1].setBounds(getWidth(), getHeight()); m_ball[1].move(); // Move the ball. repaint(); // Repaint indirectly calls paintComponent. } } } }//endclass public class Ball { //... Constants final static int DIAMETER = 50; //... Instance variables static int m_x; // x and y coordinates upper left static int m_y; ...... //public int deg=90; // Pixels to move each time move() is called. public int deg; public int offset=400; //======================================================== constructor public Ball(int x, int y, int offset, int deg) { m_x = x; m_y = y; } ......... } //============================================================== move public void move() { double degrees=(double) deg; double radians=Math.toRadians(degrees); double Sinu=Math.sin(radians); double Sinu200=Math.sin(radians)*300; int SinuInt=(int) Sinu200; m_y=offset+SinuInt; double Cos=Math.cos(radians); double Cos200=Math.cos(radians)*300; int CosInt=(int) Cos200; m_x=offset+CosInt; deg++; // j--; if (deg==360) deg=0; } //============================================================== draw public void draw(Graphics g) { g.fillOval(m_x, m_y, DIAMETER, DIAMETER); } //============================================= getDiameter, getX, getY public int getDiameter() { return DIAMETER;} public int getX() { return m_x;} public int getY() { return m_y;} //======================================================== setPosition public void setPosition(int x, int y) { m_x = x; m_y = y; } } </code></pre>

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