draw_arrow.java

基于图形的二叉树工作演示程序

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import myBag.*;
class Draw_ArrowFrame extends JFrame{
  int width=650,height=500;
  public Draw_ArrowFrame(){
    setTitle("Draw_Arrow");
    Container contentPane=getContentPane();
    contentPane.add(new Draw_ArrowPanel());
    addWindowListener(new WL());               //添加窗口事件监听器
    setSize(width,height);
  }
  class WL extends WindowAdapter{                //设置窗口事件监听器
    public void windowClosing(WindowEvent e){ System.exit(0);}
  }
  class Draw_ArrowPanel extends JPanel{
    public void paintComponent(Graphics g){
      super.paintComponent(g);
      drawArrow(g,300,100);
    }
    private void drawArrow(Graphics g, int x, int y){
      g.setColor(Color.red);
      g.drawLine(x,y,x,y-8);
      g.drawLine(x,y,x+2,y-2);
      g.drawLine(x,y,x-2,y-2);
      g.drawLine(x,y-1,x+1,y-1);
      g.drawLine(x,y-1,x-1,y-1);
    }
  }
}

public class Draw_Arrow{
  public static void main(String[]array){
    Draw_ArrowFrame f=new Draw_ArrowFrame();
    f.setVisible(true);
  }
}