Java.GUI图形操作.组件重绘

//DrawLine.java

package myprojects.drawline;
public class DrawLine {
public static void main(String[] args) {
// TODO: Add your code here
MyFrame f=new MyFrame();
f.setSize(500,500);
f.setTitle("MyFrame");
f.setVisible(true);
System.out.println("start!");

}
}

//MyFrame.java

package myprojects.drawline;

import java.util.*;
import java.awt.Frame;
import java.awt.*;
import java.awt.event.*;

public class MyFrame extends Frame {
int x1,x2,y1,y2;
Vector v=new Vector();
public MyFrame(){
enableEvents(AWTEvent.MOUSE_EVENT_MASK);
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
}

protected void processMouseEvent(MouseEvent e){
if(e.getID()==MouseEvent.MOUSE_PRESSED){
x1=e.getX();
y1=e.getY();
}
if(e.getID()==MouseEvent.MOUSE_RELEASED){
x2=e.getX();
y2=e.getY();
Graphics g=getGraphics();
g.setColor(Color.red);
g.setFont(new Font("隶书",Font.ITALIC,30));//设置文本字体
g.drawString(new String(x1+","+y1),x1,y1);//坐标文本和按下鼠标时的坐标
g.drawLine(x1,y1,x2,y2);
g.drawString(new String(x2+","+y2),x2,y2);
v.addElement(new MyLine(x1,y1,x2,y2));
}
}

protected void processWindowEvent(WindowEvent e){
if(e.getID()==WindowEvent.WINDOW_CLOSING){
dispose();
}
}
public void paint(Graphics g){
/*
g.setColor(Color.red);
g.setFont(new Font("隶书",Font.ITALIC,30));//设置文本字体
g.drawString(new String(x1+","+y1),x1,y1);//坐标文本和按下鼠标时的坐标
g.drawLine(x1,y1,x2,y2);
g.drawString(new String(x2+","+y2),x2,y2);
*/
Enumeration e=v.elements();
while(e.hasMoreElements()){
MyLine ln=(MyLine)e.nextElement();
Thread.sleep(5000);
ln.drawLine(g);
}
}
}

//MyLine.java

package myprojects.drawline;
import java.awt.*;

public class MyLine {
int x1,x2,y1,y2;
public MyLine(int x1,int y1,int x2,int y2){
this.x1=x1;
this.y1=y1;
this.x2=x2;
this.y2=y2;
}
public void drawLine(Graphics g){
g.setColor(Color.red);
g.setFont(new Font("隶书",Font.ITALIC,30));//设置文本字体
g.drawString(new String(x1+","+y1),x1,y1);//坐标文本和按下鼠标时的坐标
g.drawLine(x1,y1,x2,y2);
g.drawString(new String(x2+","+y2),x2,y2);
}
}