java Jpanel调用另一个Jpanel时的paint函数异常

[tanweijia888]

想在java里面的一个jpanel里面调用另一个jpanel，发现这个第二个jpanel里面的paint函数有异常，是咋回事呢？

class Packet extends JPanel
{
   private double s_x,s_y,e_x,e_y;
   private String s_ID;
   private Double move_time;
   private double a,b,c;
   private double receiver_sped;
   private double step;
   private int x,y;
   
   public Packet(int cs_x,int cs_y,int ce_x,int ce_y,double cmove_time,double creceiver_sped,String cs_ID)
   {
	  
	   this.s_x=cs_x;
	   this.s_y=cs_y;
	   this.e_x=ce_x;
	   this.e_y=ce_y;
	   this.move_time=cmove_time;
	   this.receiver_sped=creceiver_sped;
	   this.s_ID=cs_ID;
	   //System.out.println("SX:"+s_x+" "+"SY:"+s_y+" "+"EX:"+e_x+" "+"EY:"+e_y+" "+"Mtime:"+move_time+" "+"rsped:"+receiver_sped+" "+"ID:"+s_ID);
	   
	   getTarget();
	   //System.out.println("Packet_public_2");
	  // run();
	   //System.out.println("Packet_public_3");
	  
	 
	   
   }
   public void getTarget() {
		
		double x1 = this.s_x;
		double y1 = this.s_y;
		double x3 = e_x;
		double y3 = e_y-this.move_time*this.receiver_sped;
		a = (float) (y3 - y1) / (float) (x3 - x1);
		b = (float) (y3 * (x3 - x1) - x3 * (y3 - y1)) / (float) (x3 - x1);
		step =  (x3 - x1)/(this.move_time);
		//System.out.println("ID:"+this.s_ID);
		//System.out.println("x1:"+x1+" "+"y1:"+y1+" "+"x3:"+x3+" "+"y3:"+y3+" "+"a:"+a+" "+"b:"+b+" "+"step:"+step);
	}
   


	public void paint(Graphics g)  
	{
		super.paint(g);
			//System.out.println("run_x:"+x);
			x += 50;
			if(x>this.e_x)
				x=(int)this.s_x;
			y = (int) (a * x + b);
			if (y > this.e_y) {
				//_z.isLive = false;
			}
		
		System.out.println("ID:"+this.s_ID);
		//g.setColor(Color.BLUE);
		//g.fillRect(x, y, 20, 20);
		g.setColor(Color.RED);
		g.drawString(this.s_ID, x, y+20);
		//repaint();
	}
  
}

构造器里的ID和paint函数里的ID不同，

[业余草]

报什么异常，写清楚，顶你

[tanweijia888]

引用 1 楼 xmt1139057136 的回复:

报什么异常，写清楚，顶你

没报异常，程序能正常运行，就是在构造器public Packet里面打印出来的s_ID和在paint函数里打印出来的s_ID不一致，在paint函数里会打印出先前赋值时的s_ID。整个程序还有一个JPanel类，在这个类里面有一个for循环，满足一定条件时就new Packet，然后传值给这个Packet。现在就是不清楚为什么同一个变量打印出来的东西不一样呢？

[tanweijia888]

if (Double.parseDouble(timeStr(Start)) == open.STIME[i]){

				Packet packet = new Packet(senderX, senderY, receiverX, receiverY,
						open.move_time[i], (double) delay1[receiverID] / 1000,
						open.sender[i][5]);
				add(packet);
				packet.setOpaque(false);
				packet.setBounds(0, 0, 800, 1000);
}

这个是之前的初始化条件语句