mycanvas.java

来自「JAVA游戏开发的基本框架设计」· Java 代码 · 共 96 行

import javax.microedition.lcdui.*;

public class MyCanvas extends Canvas implements Runnable
{
	Image ballImage;
	Image bufferImage;
	int ballX, ballY;
	public MyCanvas()
	{
		bufferImage = Image.createImage(176, 208);
		try
		{
			ballImage = Image.createImage("/d.png");
		}
		catch(java.io.IOException ioe)
		{
			System.out.println("Can not open Image file");
		}
		
		Thread t = new Thread(this);
		t.start();
	}
	
	boolean xdown = true;
	boolean ydown = true;
	int whichframe;
	final int SPEED = 4;
	public void run()
	{
		Graphics g = bufferImage.getGrahpics();
		while(true)
		{
			
			if(xdown)
			{
				ballX+=SPEED;
			}
			else
			{
				ballX-=SPEED;
			}
			if(ydown)
			{
				ballY+=SPEED;
			}
			else
			{
				ballY-=SPEED;
			}
			
			if(ballX + 16 > 176 || ballX < 0)
			{
				xdown = !xdown;
				whichframe++;
			}
			
			if(ballY + 16 > 208 || ballY < 0)
			{
				ydown = !ydown;
				whichframe++;
			}
			
			
			bufferPaint(g);
			repaint();
			try
			{
				Thread.sleep(50);
			}
			catch(Exception e)
			{
				
			}
		}
	}
	
	public void bufferPaint(Graphics g)
	{
		g.setColor(255, 255, 255);
		g.fillRect(0, 0, 176, 208);
		
		g.translate(-g.getTranslateX(), - g.getTranslateY());
		g.translate(ballX, ballY);
		g.setClip(0, 0, 16, 16);
		g.drawImage(ballImage, -16 * (whichframe % 3), 0, 0);
	}
	
	public void paint(Graphics g)
	{
		g.setColor(0);
		g.fillRect(0, 0, getWidth(), getHeight());
		g.setColor(255, 0, 0);
		
		g.drawImage(bufferImage, getWidth() - 176 >> 1, getHeight() - 208 >> 1, 0);
	}
}