tickerdemo.java

来自「j2me学习 简单例子」· Java 代码 · 共 89 行

package example.demoseniorui.ticker;

import 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.Ticker;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

/**
 * <p>J2ME Ticker Demo</p>
 * 
 * @author 刘光辉
 * @version 2009.02.02
 */
public class TickerDemo extends MIDlet implements CommandListener {

	private static final String TICKER_TEXT = "This is a ticker see it " + 
		"scroll along the way... On and on it goes without " +
		"stopping even for a second!";
	private static final Command CMD_EXIT = new Command("Exit",Command.EXIT,1);
	private boolean firstTime;
	private Display display;
	private Form mainForm;
	private Ticker ticker;
	
	/**
	 * <p>TickerDemo的构造函数</p>
	 */
	public TickerDemo() {
		display = Display.getDisplay(this);
		firstTime = true;
		mainForm = new Form("Ticker");
		mainForm.setCommandListener(this);
	}

	/**
	 * <p>启动程序,使MIDlet处于active状态</p>
	 * <p></p>
	 * @see javax.microedition.midlet.MIDlet#startApp()
	 */
	protected void startApp() throws MIDletStateChangeException {
		if(firstTime){
			ticker = new Ticker(TICKER_TEXT);
			mainForm.setTicker(ticker);
			firstTime = false;			
		}
        mainForm.addCommand(CMD_EXIT);
        display.setCurrent(mainForm);
	}
	
	/**
	 * <p>暂停程序,使MIDlet处于pause状态</p>
	 * @see javax.microedition.midlet.MIDlet#pauseApp()
	 */
	protected void pauseApp() {

	}

	/**
	 * <p>销毁程序,使MIDlet处于destroyed状态</p>
	 * 
	 * @param boolean unconditional 
	 * <ul>true 释放资源保存数据进入destroyed状态,false 抛出异常保持当前状态</ul>
	 * @see javax.microedition.midlet.MIDlet#destroyApp(boolean)
	 */
	protected void destroyApp(boolean unconditional) throws MIDletStateChangeException {
		display.setCurrent(null);
		notifyDestroyed();
	}

	/**
	 * <p>命令处理函数,实现CommandListener接口</p>
	 * @param Command c 命令对象
	 * @param Displayable d 被放置到显示屏显示的对象
	 */
	public void commandAction(Command c, Displayable d) {
		if(c == CMD_EXIT){
			try {
				destroyApp(true);
			} catch (MIDletStateChangeException e) {
				e.printStackTrace();
			}
		}
	}
}