画三角形

package com032602;

import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JFrame;

import com032602.DrawBorder;
import com032602.DrawListener;

public class DrawBorder extends JFrame{
	//定义主函数
	public static void main(String[] args){
		//实例化DrawBorder类的对象
	DrawBorder db=new DrawBorder();
	//调用initUI函数
	db.initUI();	
	}
	//定义一个initUI函数
	public void initUI(){
		//设置属性值
		this.setTitle("");
		this.setSize(800, 900);
		this.setDefaultCloseOperation(3);
		this.setResizable(true);
		this.setLocationRelativeTo(null);
		this.setLayout(new FlowLayout());
		
		JButton butLine=new JButton("Line");
		JButton butRect=new JButton("Rect");
		JButton butOval=new JButton("Oval");
		JButton butColor=new JButton("Color");
		
		this.add(butLine);
		this.add(butRect);
		this.add(butOval);
		this.add(butColor);
		
		ActionListener a=new ActionListener(){
			public void actionPerformed(ActionEvent e){
				if(e.getActionCommand().equals("Color")){
					color=JColorChooser.showDialog(null, "颜色的选择", Color.black);
						System.out.println("Color="+color);
				}
				
			}
			
	  };
	  butLine.addActionListener(a);
		butRect.addActionListener(a);
		butOval.addActionListener(a);
		butColor.addActionListener(a);
		
		
		
		this.setVisible(true);
		 
		Graphics g=this.getGraphics();
		DrawListener d=new DrawListener(g);
		this.addMouseListener(d);
		
		
	}
	public static Color color=Color.black;
	
}


package com032602;

import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

public class DrawListener implements MouseListener{
    public int x1,x2,y1,y2;
  public int x,y;
   Graphics g;

   public DrawListener(Graphics g){
		this.g=g;
	}
	

	public void mousePressed(MouseEvent e) {
		x1=e.getX();
		y1=e.getY();
	}

	public void mouseReleased(MouseEvent e) {
		System.out.print("ssss");
		x2=e.getX();
		y2=e.getY();
		g.setColor(DrawBorder.color);

		this.Draw(e);
		}
		
	public void Draw(MouseEvent e){
			for(int i=0;i<100;i++){
				g.drawLine(x1, y1,x2,y1);
				
				x1--;y1=y1+2;x2++;
						
				
			}
	
			
		
		
		
}
		
	
	

	public void mouseEntered(MouseEvent e) {
		
	}

	public void mouseExited(MouseEvent e) {
		
	}
	public void mouseClicked(MouseEvent e) {
		
	}

	

}