tickerdemo.java

《J2ME图形应用基础》中的例子

/*
 *  TickerTest.java
 *
 * Created on 2005年3月1日, 上午11:14
 */

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

/**
 * TickerTest demonstrates the ticker component
 *
 * @see MIDlet
 */
public class TickerDemo extends MIDlet implements CommandListener {
    
    //Display管理
    Display display = null;
    
    //Form对象
    Form form = new Form("这是窗口的标题");
    //Ticker对象
    Ticker ticker = new Ticker("这是滚动文字");
    
    //创建命令按钮
    static final Command cmdAddTitle =
            new Command("显示标题", Command.ITEM,1);
    static final Command cmdRemoveTitle =
            new Command("删除标题", Command.ITEM,1);
    static final Command cmdAddTicker =
            new Command("显示滚动条", Command.ITEM,1);
    static final Command cmdRemoveTicker =
            new Command("删除滚动条", Command.ITEM,1);
    static final Command cmdAddStringLine =
            new Command("添加一行滚动文字", Command.ITEM,1);
    static final Command cmdGetTickerString =
            new Command("获得滚动文字", Command.ITEM,1);
    static final Command cmdExit = new Command("退出", Command.STOP, 2);
    
    int count = 1;
    
    public void startApp() throws MIDletStateChangeException {
        //设置Displayable对象
        form.addCommand(cmdExit);
        form.addCommand(cmdAddTitle);
        form.addCommand(cmdRemoveTitle);
        form.addCommand(cmdAddTicker);
        form.addCommand(cmdRemoveTicker);
        form.addCommand(cmdAddStringLine);
        form.addCommand(cmdGetTickerString);
        form.setCommandListener(this);
        
        //显示滚动条
        form.setTicker(ticker);
        
        display = Display.getDisplay(this); //获得当前MIDlet的Display对象
        display.setCurrent(form);           //设置form对象为当前显示对象
    }
    
    public void pauseApp() {
    }
    
    public void destroyApp(boolean unconditional) {
        notifyDestroyed();
    }
    
    /**
     * 处理命令按钮事件
     */
    public void commandAction(Command c, Displayable d) {
        String label = c.getLabel();
        if (label.equals("退出")) {
            destroyApp(true);
        } else if(label.equals("显示标题")) {
            form.setTitle("显示标题");
        } else if(label.equals("删除标题")) {
            form.setTitle(null);
        } else if(label.equals("显示滚动条")) {
            form.setTicker(ticker);
        } else if(label.equals("删除滚动条")) {
            form.setTicker(null);
        } else if(label.equals("添加一行滚动文字")) {
            count++;
            ticker.setString(ticker.getString() + "\n" + 
                    "第" + count + "行滚动文字");
        } else if(label.equals("获得滚动文字")) {
            form.append("获得滚动文字：" + form.getTicker().getString());
        }
    }
}