这个代码为什么显示不出来…想得我头都大了

[rongyunsheng]

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.lang.Math;
public class TestSin extends JFrame{
 private DisplayPanel dp;
  
public void TestSin(){
 setLayout(new BorderLayout());
 dp=new DisplayPanel(this);
 getContentPane().add(dp,"Center");
 setLocation(200,200);
 pack();
 setVisible(true);
 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);	
} 
 public static void main(String []args){
 new TestSin();
   }

 class DisplayPanel extends JPanel implements Runnable,MouseListener{
  private TestSin ts;
  Thread th;
  double c=0.0;
  double a=100.0;
  boolean stopIt=false;
  public DisplayPanel(TestSin tsi){
  	ts=tsi;
    setBackground(Color.pink);

 // setCursor(Cursor.WAIT_CURSOR); 这里为什么不对啊？？
    setPreferredSize(new Dimension(300,700));
    addMouseListener(this);
    th=new Thread(this);
    th.start();
    }
   public void paint(Graphics g){
   	Graphics2D g1=(Graphics2D)g;
   	ts.setTitle("C ="+c);
   	g1.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
   	//也可以用super.paint();
   	g1.clearRect(0,0,getSize().width,getSize().height);
   	g1.setColor(Color.blue);
   	for(int i=0;i<getSize().width;i++){
   	g1.drawLine(i,(int)(Math.sin(i/a+c)*a+getSize().height/2),
   	            i+1,(int)(Math.sin(i+1/a+c)*a+getSize().height/2) );
   	}
   	}
    public void run(){
     while(!stopIt){
     c+=0.1;
     repaint(); 	
     if(c>=2*Math.PI*getSize().width) 
     {c=0.0;}
     }
     try{
      th.sleep(1000);
     }
     catch(InterruptedException ex)
     {ex.printStackTrace();}	
    }
    public  void mouseClicked(MouseEvent e){}
    
    public  void mousePressed(MouseEvent e){}
    
    public  void mouseReleased(MouseEvent e){stopIt=!stopIt;}
    
    public  void mouseEntered(MouseEvent e){}
    
    public  void mouseExited(MouseEvent e){}   
   }
   }

编译通过，就是结果显示不出来
本意是想输出一段动态的SIN曲线

[mhoudg]

楼主啊

public void TestSin(){

这不是构造方法啊
构造方法不能有返回值
改成

public TestSin(){

就可以了

[carnation003]

setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));

[carnation003]

Format了一下：

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.lang.Math;

public class TestSin extends JFrame {

	private DisplayPanel dp;

	public TestSin() {
		setLayout(new BorderLayout());
		dp = new DisplayPanel(this);
		getContentPane().add(dp, "Center");
		setLocation(200, 200);
		pack();
		setVisible(true);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}

	public static void main(String[] args) {
		new TestSin();
	}

	class DisplayPanel extends JPanel implements Runnable, MouseListener {

		private TestSin ts;

		Thread th;

		double c = 0.0;

		double a = 100.0;

		boolean stopIt = false;

		public DisplayPanel(TestSin tsi) {
			ts = tsi;
			setBackground(Color.pink);

			setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
			setPreferredSize(new Dimension(300, 700));
			addMouseListener(this);
			th = new Thread(this);
			th.start();
		}

		public void paint(Graphics g) {
			Graphics2D g1 = (Graphics2D) g;
			ts.setTitle("C =" + c);
			g1.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
					RenderingHints.VALUE_ANTIALIAS_ON);
			// 也可以用super.paint();
			g1.clearRect(0, 0, getSize().width, getSize().height);
			g1.setColor(Color.blue);
			for (int i = 0; i < getSize().width; i++) {
				g1.drawLine(i, (int) (Math.sin(i / a + c) * a + getSize().height / 2),
						i + 1, (int) (Math.sin(i + 1 / a + c) * a + getSize().height / 2));
			}
		}

		public void run() {
			while (!stopIt) {
				c += 0.1;
				repaint();
				if (c >= 2 * Math.PI * getSize().width) {
					c = 0.0;
				}
			}
			try {
				Thread.sleep(1000);
			} catch (InterruptedException ex) {
				ex.printStackTrace();
			}
		}

		public void mouseClicked(MouseEvent e) {
		}

		public void mousePressed(MouseEvent e) {
		}

		public void mouseReleased(MouseEvent e) {
			stopIt = !stopIt;
		}

		public void mouseEntered(MouseEvent e) {
		}

		public void mouseExited(MouseEvent e) {
		}
	}
}