K_java手机开发中获取设备信息（k_eckel转自微软高校博客K_eckel's mindview）

    K_java平台上的开发时候，由于不同的支持J2ME的手持设备的性能是不同的，我们希望能够获得设备的具体信息，比如设备是否支持彩色以及支持的颜色数量、屏幕的宽度和高度、是否支持触摸屏等等。前者在Display类中通过isColor（）方法和numColors（）方法来获取，后者则可以通过Canvas类中getWidth（）等方法实现。以下给出示例代码供参考（代码在MIDP1.0、CLDC1.0下运行通过）：

DevParaCap.java

import javax.microedition.midlet.MIDlet;

import javax.microedition.midlet.MIDletStateChangeException;

 

import javax.microedition.lcdui.Canvas;

import javax.microedition.lcdui.Command;

import javax.microedition.lcdui.CommandListener;

import javax.microedition.lcdui.Display;

import javax.microedition.lcdui.Displayable;

import javax.microedition.lcdui.Graphics;

 

/*

 * Created on 2005-5-16

 *

 * TODO To change the template for this generated file go to

 * Window - Preferences - Java - Code Style - Code Templates

 */

 

/**

 * @author k_eckel

 *

 * TODO To change the template for this generated type comment go to

 * Window - Preferences - Java - Code Style - Code Templates

 */

 

public class DevParaCap extends MIDlet implements CommandListener{

       private Display dis = null;

       private Command cmdExit;

       private Canvas canvas;

 

       /**

        *

        */

       public DevParaCap() {

              super();

              //

              cmdExit = new Command("Exit",Command.EXIT,1);

              canvas = new Canvas()

              {

                     public void paint(Graphics g){

                            }

              };

             

              canvas.addCommand(cmdExit);

              canvas.setCommandListener(this);

       }

 

       /* (non-Javadoc)

        * @see javax.microedition.midlet.MIDlet#startApp()

        */

       protected void startApp() throws MIDletStateChangeException {

              // TODO Auto-generated method stub

              dis = Display.getDisplay(this);

              getDevCapability(dis,canvas);

             

              dis.setCurrent(canvas);

 

       }

 

       /* (non-Javadoc)

        * @see javax.microedition.midlet.MIDlet#pauseApp()

        */

       protected void pauseApp() {

              // TODO Auto-generated method stub

 

       }

 

       /* (non-Javadoc)

        * @see javax.microedition.midlet.MIDlet#destroyApp(boolean)

        */

       protected void destroyApp(boolean arg0) throws MIDletStateChangeException {

              // TODO Auto-generated method stub

              this.notifyDestroyed();

 

       }

      

       public static void getDevCapability(Display d,Canvas c)

       {

              System.out.println("支持彩色: " + d.isColor());

              System.out.println("颜色数量: " + d.numColors());

              System.out.println("正常屏幕宽度: " + c.getWidth());

              System.out.println("正常屏幕高度: " + c.getHeight());

              System.out.println("支持触摸屏设备: " + c.hasPointerEvents());

              System.out.println("支持触摸屏拖放: " + c.hasPointerMotionEvents());

              System.out.println("支持重复按键事件: " + c.hasRepeatEvents());

             

       }

      

       public void commandAction(Command c,Displayable d)

       {

              if (c == cmdExit)

              {

                     try

                     {

                            destroyApp(false);

                            notifyDestroyed();

                     }

                     catch (MIDletStateChangeException e)

                     {

                     e.printStackTrace();

                     }

              }

             

       }

 

}

 

       在模拟器上运行的结果为：

支持彩色: true

颜色数量: 4096

正常屏幕宽度: 240

正常屏幕高度: 289

支持触摸屏设备: false

支持触摸屏拖放: false

支持重复按键事件: false

 

   结果的含义我就不罗嗦了：）。