simpledraw.java

来自「疯狂Java讲义_源码(含Java设计模式CHM」· Java 代码 · 共 84 行

import java.awt.*;
import java.awt.event.*;
import java.util.Random;

/**
 * Description:
 * <br/>Copyright (C), 2005-2008, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [e-mail]
 * @version  1.0
 */
public class SimpleDraw
{
	private final String RECT_SHAPE = "rect";
	private final String OVAL_SHAPE = "oval";
	private Frame f = new Frame("简单绘图");
	private Button rect = new Button("绘制矩形");
	private Button oval = new Button("绘制圆形");
	private MyCanvas drawArea = new MyCanvas();
	//用于保存需要绘制什么图形的字符串属性
	private String shape = "";
	public void init()
	{
		Panel p = new Panel();
		rect.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				//设置shape属性为RECT_SHAPE
				shape = RECT_SHAPE;
				//重画MyCanvas对象，即调用它的update方法
				drawArea.repaint();
			}
		});
		oval.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				//设置shape属性为OVAL_SHAPE
				shape = OVAL_SHAPE;
				//重画MyCanvas对象，即调用它的update方法
				drawArea.repaint();
			}
		});
		p.add(rect);
		p.add(oval);
		drawArea.setPreferredSize(new Dimension(250 , 180));
		f.add(drawArea);
		f.add(p , BorderLayout.SOUTH);
		f.pack();
		f.setVisible(true);
	}

	public static void main(String[] args) 
	{
		new SimpleDraw().init();
	}
	class MyCanvas extends Canvas
	{
		//重写Canvas的paint方法，实现绘画
		public void paint(Graphics g)
		{
			Random rand = new Random();
			if (shape.equals(RECT_SHAPE))
			{
				//设置画笔颜色
				g.setColor(new Color(220, 100, 80));
				//随机地绘制一个矩形框
				g.drawRect( rand.nextInt(200) , rand.nextInt(120) , 40 , 60);
			}
			if (shape.equals(OVAL_SHAPE))
			{
				//设置画笔颜色
				g.setColor(new Color(80, 100, 200));
				//随机地绘制一个矩形框
				g.fillOval( rand.nextInt(200) , rand.nextInt(120) , 50 , 40);
			}
		}
	}
}