学步园

 主要是学习游戏速度的调整，小球移动速度的改变，连续按键与非连续按键的控制。

最终效果图：

下边帖出代码，MIDlet类就不贴了

GameCanvas类

package speedBall;</p> <p>import javax.microedition.lcdui.*;</p> <p>/**<br /> * 小球速度的改变<br /> *<br /> * @author kf156(亚日)<br /> *<br /> */<br /> public class GameCanvas extends Canvas implements Runnable {<br /> public final static int KEY_UP = -1;// 上</p> <p> public final static int KEY_DOWN = -2;// 下</p> <p> public final static int KEY_LEFT = -3;// 左</p> <p> public final static int KEY_RIGHT = -4;// 右</p> <p> public final static int SPEED_UP = -6; // 功能键 左 1</p> <p> public final static int SPEED_DOWN = -7; // 功能键 右 2</p> <p> public boolean running;</p> <p> private Thread thread;</p> <p> private int[] key = new int[4];</p> <p> private int width;</p> <p> private int height;</p> <p> private int Speed;// 游戏速度（利用线程休眠时间来控制）</p> <p> public Font font;</p> <p> private final int DIAMETER = 20;// 小球直径</p> <p> public boolean flagX, flagY;// XY方向标记</p> <p> int ballX, ballY;// 小球坐标</p> <p> int x, y;// XY方向移动速度</p> <p> public GameCanvas() {<br /> setFullScreenMode(true);<br /> font = Font.getFont(Font.FACE_SYSTEM, Font.STYLE_PLAIN,<br /> Font.SIZE_MEDIUM);<br /> width = getWidth();<br /> height = getHeight();<br /> running = true;<br /> x = 4;<br /> y = 4;<br /> ballX = 0;<br /> ballY = 0;<br /> flagX = true;<br /> flagY = true;<br /> Speed = 50;<br /> startThread();<br /> }</p> <p> public void startThread() {<br /> if (thread == null)<br /> thread = new Thread(this);<br /> thread.start();<br /> }</p> <p> public void showNotify() {</p> <p> }</p> <p> public void init() {</p> <p> }</p> <p> public void free() {</p> <p> }</p> <p> public void input() {<br /> key[0] = key[2];<br /> key[1] = key[3];<br /> key[2] = 0;<br /> }</p> <p> public void update() {</p> <p> switch (key[0]) {// 非连接按键<br /> case KEY_UP:<br /> if (y > 0)<br /> y--;<br /> break;</p> <p> case KEY_DOWN:<br /> if (y < 20)<br /> y++;<br /> break;</p> <p> case KEY_LEFT:<br /> if (x > 0)<br /> x--;<br /> break;</p> <p> case KEY_RIGHT:<br /> if (x < 20)<br /> x++;<br /> break;<br /> }</p> <p> switch (key[1]) {// 连续按键控制<br /> case SPEED_UP:// 加速<br /> Speed--;<br /> break;<br /> case SPEED_DOWN:// 减速<br /> Speed++;<br /> break;<br /> }</p> <p> // 限制速度范围<br /> if (Speed < 1)<br /> Speed = 1;<br /> else if (Speed > 50)<br /> Speed = 50;</p> <p> ballX += flagX ? x : -x;// 判断水平移动方向<br /> ballY += flagY ? y : -y;// 判断垂直移动方向</p> <p> // 边界判断</p> <p> if (ballX > width - DIAMETER) {// 右边界<br /> ballX = width - DIAMETER;<br /> flagX = false;</p> <p> } else if (ballX < 0) {// 左边界<br /> ballX = 0;<br /> flagX = true;<br /> }</p> <p> if (ballY > height - DIAMETER) {// 下边界<br /> ballY = height - DIAMETER;<br /> flagY = false;</p> <p> } else if (ballY < 0) {// 上边界<br /> ballY = 0;<br /> flagY = true;<br /> }</p> <p> }</p> <p> protected void paint(Graphics g) {<br /> // 背景填充<br /> g.setColor(0);<br /> g.fillRect(0, 0, width, height);</p> <p> // 绘制小球<br /> g.setColor(0xff0000);<br /> g.fillArc(ballX, ballY, DIAMETER, DIAMETER, 0, 360);</p> <p> // 文字<br /> g.setColor(0x00ffff);<br /> g.drawString("游戏速度为：" + (51 - Speed), width >> 1, (height >> 1)<br /> - font.getHeight(), Graphics.HCENTER | Graphics.TOP);<br /> g.drawString("X方向移动速度：" + x, width >> 1, height >> 1, Graphics.HCENTER<br /> | Graphics.TOP);<br /> g.drawString("Y方向移动速度：" + y, width >> 1, (height >> 1)<br /> + font.getHeight(), Graphics.HCENTER | Graphics.TOP);</p> <p> g.drawString("加速", 0, height - font.getHeight(), 20);<br /> g.drawString("减速", width, height - font.getHeight(), 24);</p> <p> }</p> <p> public void run() {<br /> int debug = 0;<br /> try {<br /> while (running) {<br /> // 真机上用次方法<br /> long stare = System.currentTimeMillis();<br /> input();<br /> debug = 1;<br /> update();<br /> debug = 2;<br /> repaint();<br /> serviceRepaints();<br /> long end = System.currentTimeMillis() - stare;<br /> if (end < Speed)<br /> Thread.sleep(Speed - end);<br /> }<br /> GameMidlet.quitApp();<br /> } catch (Exception e) {<br /> System.err.println("run error:" + e + " debug:" + debug);<br /> }</p> <p> }</p> <p> /***************************************************************************<br /> * 重载的FullCanvas的按键触发的方法<br /> *<br /> * @param keyCode<br /> * int 系统传入的按键代码<br /> **************************************************************************/<br /> protected void keyPressed(int keyCode) {<br /> key[2] = key[3] = keyCode;<br /> }</p> <p> /***************************************************************************<br /> * 重载的FullCanvas的重复一个按键触发的方法<br /> *<br /> * @param keyCode<br /> * 系统传入的按键代码<br /> **************************************************************************/<br /> protected void keyRepeated(int keyCode) {<br /> }</p> <p> /***************************************************************************<br /> * 重载的FullCanvas的释放一个按键触发的方法<br /> *<br /> * @param keyCode<br /> * 系统传入的按键代码<br /> **************************************************************************/<br /> public void keyReleased(int keyCode) {<br /> key[3] = 0;<br /> }</p> <p>}<br />

工程已经上传，觉得网页上看不方便的朋友也可直接下载：http://download.csdn.net/source/1573193