1、J2ME 欢迎界面的代码目 录方法一 1【1】功能 1【2】代码 1【3】运行截图 3运行正常的 3运行出错的 4方法二 5【1】功能 5【2】代码 6【3】运行截图 8运行正常的 8运行出错的 91方法一【1 】 功能显示欢迎界面，按任意键进入系统，按退出键，退出程序。【2 】 代码文件名：welcomeMidlet.javapackage test;import javax.microedition.lcdui.Alert;import javax.microedition.lcdui.AlertType;import javax.microedition.lcdui.Canvas;imp
2、ort javax.microedition.lcdui.Command;import javax.microedition.lcdui.CommandListener;import javax.microedition.lcdui.Display;import javax.microedition.lcdui.Displayable;import javax.microedition.lcdui.Form;import javax.microedition.lcdui.Graphics;import javax.microedition.lcdui.Image;import javax.mi
3、croedition.midlet.MIDlet;import javax.microedition.midlet.MIDletStateChangeException;public class WelcomeMidlet1 extends MIDlet implements CommandListenerprivate Display display;private Image bgImage = null;private Form frm = new Form(“This is a test.“);private Command cmdOk = new Command(“确定“,Comma
4、nd.OK,1);private Command cmdExit = new Command(“退出“,Command.EXIT,2);private boolean imgexit = true;/图片存在private WelcomeCanvas wc = new WelcomeCanvas();private Alert AlertError = new Alert(“错误“,“ 资源文件不存在！“,null,AlertType.ERROR);/标题、屏幕显示内容、提示图片、错误类型public WelcomeMidlet1()/先初始化欢迎界面的背景图片try 2bgImage = I
5、mage.createImage(“/welcome2.gif“); catch (Exception e) e.printStackTrace();System.out.println(“IOException错误，图片文件不存在“ ); imgexit = false;/图片不存在protected void startApp() throws MIDletStateChangeException display = Display.getDisplay(this);if(imgexit)/图片存在，进入欢迎界面display.setCurrent(wc);wc.setTitle(“请任意
6、键进入系统。“);wc.addCommand(cmdExit);wc.setCommandListener(this);else/图片不存在，提示出错信息AlertError.setTimeout(Alert.FOREVER);display.setCurrent(AlertError);AlertError.addCommand(cmdExit);AlertError.setCommandListener(this);public class WelcomeCanvas extends Canvaspublic WelcomeCanvas()protected void paint(Grap
7、hics g) /绘制背景图片g.drawImage(bgImage,this.getWidth()/2-bgImage.getWidth()/2,this.getHeight()/2-bgImage.getHeight()/2,Graphics.TOP | Graphics.LEFT);protected void keyPressed(int keyCode)/按下任意键后，转到需要显示的界面display.setCurrent(frm);frm.addCommand(cmdOk);public void commandAction(Command c,Displayable d)if(c
8、=cmdExit)/退出this.notifyDestroyed();3protected void destroyApp(boolean arg0) throws MIDletStateChangeException protected void pauseApp() / TODO Auto-generated method stub4【3 】 运行截图运行正常的按退出键则退出程序，按其他任意键，则进入如下界面：5运行出错的改变图片名，改为一个不存在的名字，则运行效果如下：6方法二【1 】 功能显示开机界面后，按退出键退出程序，若什么也不做，等待 3 秒后自动跳转到另一界7面。【2 】 代码
9、文件名：WelcomeMidlet2.javapackage test;import javax.microedition.lcdui.Alert;import javax.microedition.lcdui.AlertType;import javax.microedition.lcdui.Canvas;import javax.microedition.lcdui.Command;import javax.microedition.lcdui.CommandListener;import javax.microedition.lcdui.Display;import javax.micr
10、oedition.lcdui.Displayable;import javax.microedition.lcdui.Form;import javax.microedition.lcdui.Graphics;import javax.microedition.lcdui.Image;import javax.microedition.midlet.MIDlet;import javax.microedition.midlet.MIDletStateChangeException;public class WelcomeMidlet2 extends MIDlet implements Com
11、mandListenerprivate Display display;private Image bgImage = null;private Form frm = new Form(“This is a test.“);private Command cmdOk = new Command(“确定“,Command.OK,1);private Command cmdExit = new Command(“退出“,Command.EXIT,2);private boolean imgexit = true;/图片存在private WelcomeCanvas wc ;private Aler
12、t AlertError = new Alert(“错误“,“ 资源文件不存在！“,null,AlertType.ERROR);/标题、屏幕显示内容、提示图片、错误类型public WelcomeMidlet2()/先初始化欢迎界面的背景图片try bgImage = Image.createImage(“/welcome.gif“); catch (Exception e) e.printStackTrace();System.out.println(“IOException错误，图片文件不存在“ ); imgexit = false;/图片不存在8protected void startA
13、pp() throws MIDletStateChangeException display = Display.getDisplay(this);if(imgexit)/图片存在，进入欢迎界面wc = new WelcomeCanvas();display.setCurrent(wc);wc.setTitle(“请等待，3秒后自动进入系统。“);wc.addCommand(cmdExit);wc.setCommandListener(this);else/图片不存在，提示出错信息AlertError.setTimeout(Alert.FOREVER);display.setCurrent(A
14、lertError);AlertError.addCommand(cmdExit);AlertError.setCommandListener(this);public class WelcomeCanvas extends Canvas implements Runnable public WelcomeCanvas()Thread thread = new Thread(this);thread.start();protected void paint(Graphics g) /绘制背景图片g.drawImage(bgImage,0,0,Graphics.TOP | Graphics.LE
15、FT);public void run()try /等待3 秒Thread.sleep(3000);catch(Exception e)e.printStackTrace();System.out.println(“线程休眠出错“);/显示需要显示的界面display.setCurrent(frm);frm.addCommand(cmdOk);public void commandAction(Command c,Displayable d)if(c = cmdExit)this.notifyDestroyed();9protected void destroyApp(boolean arg0) throws MIDletStateChangeException protected void pauseApp() / TODO Auto-generated method stub10【3 】 运行截图运行正常的3 秒后自动进入如下界面：11运行出错的出错的情况和方法一是一样的，这里就不多说了。12
