请教请教，新人不懂啊

Question

错得都类似
package shiyan;import java.awt.*;
import java.util.*;public class VirtualPlatform extends Panel
{
  public int UnitId=0;  private int num;    //record the type of mouse' moving unit
  private int prex,prey; //record the prepoint of x and y of mouse'moving
  private VirtualLab virtualLab;  public Vector vbattery=new Vector();
  public Vector vvoltageMeter=new Vector();
  public Vector vcarrentMeter=new Vector();
  public Vector velectricLight=new Vector();
  public Vector vresistance=new Vector();
  public Vector vline=new Vector();  public VirtualPlatform(VirtualLab virtualLab)
  {
    this.virtualLab=virtualLab;
    this.setBackground(new Color(200,240,200));  }  private Battery pickBattery1,pickBattery2;
  private VoltageMeter pickVoltageMeter1,pickVoltageMeter2;
  private CarrentMeter pickCarrentMeter1,pickCarrentMeter2;
  private ElectricLight pickElectricLight1,pickElectricLight2;
  private Resistance pickResistance1,pickResistance2;  private Line l;
  private int pickUnit;  //pick the number of unit
  private int from,to;
  private int fromxLeft,fromxRight,fromy;
  private int toxLeft,toxRight,tox,toy;
  public boolean controlLine=false;  //private boolean pickFixed;
  private Image offScreen;
  private Dimension offScreenSize;
  private Graphics offGraphics;  public synchronized void paint(Graphics g)
  {     Dimension d=size();
     if((offScreen==null)||(d.width!=offScreenSize.width)||(d.height!=offScreenSize.height))
     {
         offScreen=createImage(d.width,d.height);
         offScreenSize=d;
         offGraphics=offScreen.getGraphics();
     }     offGraphics.setColor(Color.black);
     offGraphics.drawRect(0,0,d.width-1,d.height-1);
     //update(offGraphics);
     if(pickUnit==1)
     {
        if(fromxRight!=0)
        {          offGraphics.drawLine(fromxRight,fromy,tox,toy);        }
        else if(fromxLeft!=0)
        {           offGraphics.drawLine(fromxLeft,fromy,tox,toy);        }
     }     if(pickUnit==2)
     {
        Line l=new Line(++UnitId);  //这里就出错了
        ....     }
     Battery b;   //这里就出错了
     for(Enumeration eb=vbattery.elements();eb.hasMoreElements();)
     {
       b=(Battery)eb.nextElement();
       b.paint(offGraphics);
     }     VoltageMeter v;  //这里就出错了
     for(Enumeration ev=vvoltageMeter.elements();ev.hasMoreElements();)
     {
        v=(VoltageMeter)ev.nextElement();
        v.paint(offGraphics);
     }     CarrentMeter c;  //这里就出错了
     for(Enumeration ec=vcarrentMeter.elements();ec.hasMoreElements();)
     {
        c=(CarrentMeter)ec.nextElement();
        c.paint(offGraphics);
     }     ElectricLight e;  //这里就出错了
     for(Enumeration ee=velectricLight.elements();ee.hasMoreElements();)
     {
        e=(ElectricLight)ee.nextElement();
        offGraphics.setColor(new Color(e.color,0,0));
        e.paint(offGraphics);
        offGraphics.setColor(Color.black);
     }     Resistance r;  //这里就出错了
     for(Enumeration er=vresistance.elements();er.hasMoreElements();)
     {
        r=(Resistance)er.nextElement();
        r.paint(offGraphics);
     }     Line l;  //这里就出错了
     for(Enumeration el=vline.elements();el.hasMoreElements();)
     {
        l=(Line)el.nextElement();
        l.paint(offGraphics);
     }
     g.drawImage(offScreen,0,0,null);  }  public synchronized boolean mouseDown(Event evt,int x,int y)
  {     update(offGraphics);
     if(controlLine==true)
     {         for(Enumeration eb=vbattery.elements();eb.hasMoreElements();)
         {
            Battery b=(Battery)eb.nextElement();    //这里就出错了
            ......           }           for(Enumeration ev=vvoltageMeter.elements();ev.hasMoreElements();)
           {
              VoltageMeter v=(VoltageMeter)ev.nextElement();   //这里就出错了 ， 以下是一些计算的式子,错的方式都差不多
              if((x>v.x+10&&x<v.x+29+10)&&(y>v.y&&y<v.y+21))
              {                 pickVoltageMeter1=v;
                 from=pickVoltageMeter1.id;
                 if(x<pickVoltageMeter1.x+14+10)
                     fromxLeft=pickVoltageMeter1.x+10;
                 else
                     fromxRight=pickVoltageMeter1.x+29+10;
                 fromy=pickVoltageMeter1.y+10;                 pickUnit=1;
                 return true;
              }            }                     
     }     for(Enumeration eb=vbattery.elements();eb.hasMoreElements();)
     {
         Battery b=(Battery)eb.nextElement();   //这里就出错了  
         if((x>b.x&&x<b.x+27)&&(y>b.y&&y<b.y+21))
         {
            num=1;
            pickBattery1=b;
            prex=x-b.x;
            prey=y-b.y;
            return true;
         }
       .......
     }
  }
.....  
}

Answer 1

你得Line类在那里呢？我只在JDK1。4 API中找到了javax.sound.sampled中有

Answer 2

Battery
VoltageMeter
CarrentMeter
ElectricLight
Resistance 
Line
上面这几个不是在jdk中的，可能是在你自己写的类中，你找找看

Answer 3

把你用到的class都import进来你是不是从哪里copy下这段程序就像运行呀应该还有别的类库你没有import进来

Answer 4

Battery
VoltageMeter
CarrentMeter
ElectricLight
Resistance 
Line
这些都是我自己定义的啊

Answer 5

是不是把用到的，自己定义的class都import进来啊？？