คือว่าผมเรียน java Applet การใช้งาน KeyListener แล้วอาจารย์ให้วงกลมวิ่งตามเส้น ผมวิ่งได้แต่เส้นตงให้มันวิ่งลงต่อไม่ได้

import java.applet.*;
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;

public class testkey extends JApplet implements KeyListener,ActionListener {
 private ImageIcon image1, image2, image3;
 private int width, height;
 private JPanel guiPanel, graphicsPanel;
 private JButton startBtn, stopBtn;
 private int xMin, xMax, yMin, yMax,xMin1, xMax1, yMin1, yMax1;
 private int x, y,x1,y1 ,size,size1, xSpeed, ySpeed, xSpeed1, ySpeed1,p=0;
 Color fgcolor;
 private char typeShape='C';

 Timer swTimer;

 public void init () {

 Container c = getContentPane();
 c.setLayout(new FlowLayout());
 startBtn = new JButton("Play");
 startBtn.addActionListener(this);
 startBtn.addKeyListener(this);
 c.add(startBtn);
 stopBtn = new JButton("Stop");
 stopBtn.addActionListener(this);
 stopBtn.addKeyListener(this);
 c.add(stopBtn);
 width = 480; height = 320;
 xMin = 50; xMax = 350;
 yMin = 50; yMax = 90;
 xSpeed = 1; ySpeed = 1;
 //x = 240; y = 160; size = 40;
 x = 50; y = 50; size = 40;
 fgcolor=Color.BLUE;
image1 = new ImageIcon( getClass().getResource("/images/htb-1.png") );
 swTimer = new Timer(10, this);
 addKeyListener( this );
 }
public void paint(Graphics g) {
 super.paint(g);
 g.drawLine(50, 70, 350, 70);
 g.drawLine(350, 70, 350, 200);
 g.drawString("xspeed : "+xSpeed,80,80);
 g.drawString("x : "+x,180,180);
 g.drawString("y : "+y,190,190);
 if(typeShape=='R'){
			g.setColor(fgcolor);
			g.fillRect(x,y,size,size);
			g.setColor(Color.BLACK);
			g.drawRect(x,y,size,size);
		}
		//else if(typeShape=='A'){
		
			//image1.paintIcon( this, g, x, y );
		
		//}
		else{
			g.setColor(fgcolor);
			g.fillOval(x,y,size,size);
			g.setColor(Color.BLACK);
			g.drawOval(x,y,size,size);
		}
		
 }

 public void keyPressed(KeyEvent event) {
 if ( event.getKeyChar() == 'p')
{
 swTimer.start();
}
 else if ( event.getKeyChar() == 's')
{
 swTimer.stop();
}
if(event.getKeyChar()=='c') typeShape='C';
		if(event.getKeyChar()=='r') typeShape='R';
		if(event.getKeyChar()=='l') typeShape='L';
		//if(event.getKeyChar()=='a') typeShape='A';
 }
 //public void keyReleased(KeyEvent event) { }
 //public void keyTyped(KeyEvent event) { }
 public void actionPerformed(ActionEvent e) {
 if (e.getSource() == startBtn) { swTimer.start(); }
 else if (e.getSource() == stopBtn) { swTimer.stop(); }
 else {
 move();
 repaint();
 }
 }
 public void move() {
 x = x + xSpeed;
 y = y + ySpeed;



 if (x < xMin) {
 x = xMin;
 xSpeed = -xSpeed;
 }
 //
//
 else if (x+size > xMax) {
 x = xMax - size;
 xSpeed = -xSpeed;
 }
 
 if (y < yMin) {
 y = yMin;
 ySpeed = -ySpeed;
 }
 else if (y+size > yMax) {
 y = yMax - size;
 ySpeed = -ySpeed;
 }

 }
 

	public void keyReleased(KeyEvent event){
		repaint();
	}

	public void keyTyped(KeyEvent event){
		Graphics g = getGraphics();
		g.drawString("keyTyped : "+event.getKeyChar(),50,50);
	}
}