ch11_5.java

java练习程序

//import java.applet.*;
import java.awt.*;

class YourCanvas extends Canvas
{
	YourCanvas()
	{
		getSize();
	}
	public void paint(Graphics g)
	{
		g.setColor(Color.red);
		g.drawString("我在画布上写字呢",6,30);
/*
		g.drawRect(3,3,40,40);
		g.drawOval(20,45,30,30);
		g.setColor(Color.yellow);
		g.fillRect(3,80,20,50);
*/
	}
	public Dimension getPreferredSize()
	{
		return new Dimension(160,40);
	}
}

class MyCanvas extends Canvas
{
	MyCanvas()
	{
		getSize();
	}
	public void paint(Graphics g)
	{
		g.setColor(Color.red);
//		g.drawString("我在画布上写字呢",6,30);

		g.drawRect(3,3,40,40);
		g.drawOval(20,45,30,30);
		g.setColor(Color.yellow);
		g.fillRect(3,80,20,50);
	}
	public Dimension getPreferredSize()
	{
		return new Dimension(200,100);
	}
}

public class Ch11_5 //extends Applet
{
	
	public static void main(String args[])
	{
		
		Frame myFrame=new Frame("带画布的窗口");
		myFrame.setLayout(new FlowLayout());
		myFrame.setSize(300,200);
		myFrame.setVisible(true);
		MyCanvas mycanvas=new MyCanvas();
		YourCanvas yourcanvas=new YourCanvas();
		myFrame.add(mycanvas);
		myFrame.add(yourcanvas);
		myFrame.add(new Button("带画布的小程序"));
		myFrame.pack();
	}
}