JAVA ME 手机程序入门级源码

 一个由 Carol Hamer 写的比较有代表性的源码，作者全力推荐，尤其是对于没有 J2ME 开发经验的朋友。自己动手敲出以下贴出的 Hello.java 和 HelloCanvas.java 源码，并运行，用心体会一下。相信你理解了此源码之后，即可步入 J2ME 开发。

注释都在源码里，运行环境自己配，自己动手看运行效果，理解之后，然后动手修改一下源码，J2ME 开发，你可以的！

Hello.java 源码：

package net.frog_parrot.hello;import javax.microedition.lcdui.*;import javax.microedition.midlet.*;/** * This is the main class of the hello world demo * * @author Carol Hamer * */public class Hello extends MIDlet implements CommandListener {/** * The canvas is the region of the screen that has bean alloted to the game */HelloCanvas myCanvas;/** * The Command objects apears as buttons. */private Command exitCommand = new Command("Exit",Command.EXIT,99);/** * The Command objects apears as buttons. */private Command newCommand = new Command("Toggle Msg",Command.SCREEN,1);/** * initialize the canvas and the commands */public Hello() {myCanvas = new HelloCanvas(Display.getDisplay(this));myCanvas.addCommand(exitCommand);myCanvas.addCommand(newCommand);myCanvas.setCommandListener(this);}//--------------------------------// implementation of MIDlet/** * Start the application */protected void startApp() throws MIDletStateChangeException {myCanvas.start();}/** * This method is called to notify the MIDlet to enter a paused state. * The MIDlet should use this opportunity to release shared resources. */protected void pauseApp() {}/** * If the MIDlet was using resources,it should release them in this method */protected void destroyApp(boolean arg0) throws MIDletStateChangeException {}//-----------------------// implementation of CommandListener./** * Respond to a command issued on the Canvas * (either reset or exit) */public void commandAction(Command c, Displayable s) {if(c == newCommand) {myCanvas.newHello();}else if(c == exitCommand) {try {destroyApp(false);notifyDestroyed();} catch (MIDletStateChangeException e) {}}}}

 HelloCanvas.java 源码：

package net.frog_parrot.hello;import javax.microedition.lcdui.Display;import javax.microedition.lcdui.Font;import javax.microedition.lcdui.Graphics;import javax.microedition.lcdui.game.GameCanvas;/** * This class represents the region of the screen that has bean alloted to the game * * @author Carol Hamer * */public class HelloCanvas extends GameCanvas {//------------------------//fields/** * A handle to the screen of the device */Display myDisplay;/** * Whether or not the screen should currently display the "Hello world" message. */boolean mySayHello = true;//-------------------------------//initialization and game state changes/** * Constructor merely sets the display */public HelloCanvas(Display d) {super(false);myDisplay = d;}/** * This is called as soon as the application begins */void start() {myDisplay.setCurrent(this);repaint();}/** * toggle the hello message */void newHello() {mySayHello = !mySayHello;//paint the displayrepaint();}//------------------------------------//graphics methods/** * clear the screen and display the hello world message if appropriate. */public void paint(Graphics g) {// x and y are the coordinates of the top corner of the game's dispaly areaint x = g.getClipX();int y = g.getClipY();// w and h are are the width and height of the display area:int w = g.getClipWidth();int h = g.getClipHeight();// clear the screen (paint it white):g.setColor(0xffffff);g.fillRect(x, y, w, h);//display the hello world message if appropriate:if(mySayHello) {Font font = g.getFont();int fontHeight = font.getHeight();int fontWidth = font.stringWidth("Hello World!");// set the text color to red:g.setColor(0x00ff0000);g.setFont(font);// write the string in the center of the screen:g.drawString("Hello World!", (w-fontWidth)/2, (h-fontHeight)/2, g.TOP|g.LEFT);}}}

注：本文源码来自于 Carol Hamer 写的 《一步一步学习 midp2.0 编程》，这本书的中译本已经共享至我的 csdn 资源，pdf 格式的，有兴趣的朋友可以去下载下来看看。如果你还徘徊在 J2ME 游戏开发的大门之外，并且找不着比较好的入门资料和源代码，那么这本书就是为不得其门而入的你写的！