propexample.java

这是手机下载网络图像源码 共初学者参考

/*
 * @(#)PropExample.java	1.2 03/01/22
 *
 * Copyright (c) 1999-2003 Sun Microsystems, Inc. All rights reserved. 
 * PROPRIETARY/CONFIDENTIAL
 * Use is subject to license terms
 */

package example;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

/**
 * An example MIDlet shows the values of the system properties.
 * Refer to the startApp, pauseApp, and destroyApp
 * methods so see how it handles each requested transition.
 */
public class PropExample extends MIDlet implements CommandListener {
    private Display display;
    private Form props;
    private StringBuffer propbuf;
    private Command exitCommand = new Command("Exit", Command.EXIT, 1);

    private boolean firstTime;

    /*
     * Construct a new PropExample.
     */
    public PropExample() {
        display = Display.getDisplay(this);
        firstTime = true;
        props = new Form("System Properties");
    }

    /**
     * Show the value of the properties
     */
    public void startApp() {
        Runtime runtime = Runtime.getRuntime();
        runtime.gc();
        long free = runtime.freeMemory();
        if(firstTime) {            
            long total = runtime.totalMemory();
                
            propbuf = new StringBuffer(50);
        
            props.append("Free Memory = " + free + "\n");
            props.append("Total Memory = " + total + "\n");
        
            props.append(showProp("microedition.configuration"));
            props.append(showProp("microedition.profiles"));
        
            props.append(showProp("microedition.platform"));
            props.append(showProp("microedition.locale"));
            props.append(showProp("microedition.encoding"));
        
            props.addCommand(exitCommand);
            props.setCommandListener(this); 
            display.setCurrent(props); 
            firstTime = false;
        } else {
            props.set(0, new StringItem("", "Free Memory = " + free + "\n"));
        }
        display.setCurrent(props);      
    }

    public void commandAction(Command c, Displayable s) {
        if (c == exitCommand) {
            destroyApp(false);
            notifyDestroyed();
        }	
    }

    /**
     * Show a property.
     */
    String showProp(String prop) {
        String value = System.getProperty(prop);
        propbuf.setLength(0);
        propbuf.append(prop);
        propbuf.append(" = ");
        if (value == null) {
            propbuf.append("<undefined>");
        } else {
            propbuf.append("\"");
            propbuf.append(value);
            propbuf.append("\"");
        }
        propbuf.append("\n");
        return propbuf.toString();
    }

    /**
     * Time to pause, free any space we don't need right now.
     */
    public void pauseApp() {
    }

    /**
     * Destroy must cleanup everything.
     */
    public void destroyApp(boolean unconditional) {
    }

}