screensaver.java

自己做的几个j2me程序例子。。只要在Jbuilder里open project就行。。大家看看很有代表性

package screensaver;

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

public class ScreenSaver extends MIDlet {
  private Display display; // 当前舞台
  private Timer timer; // 定时器
  private LinesTimerTask task; // 定时执行的任务
  private ScreenSaverCanvas canvas; // 绘制线条的类

  public ScreenSaver() {
    display = Display.getDisplay(this);
    canvas = new ScreenSaverCanvas(this);

    // 每隔半秒钟执行一次任务
    timer = new Timer();
    task = new LinesTimerTask(canvas);
    timer.schedule(task, 0, 500);
  }

  protected void startApp() {
    display.setCurrent(canvas);
  }

  protected void pauseApp() {}

  protected void destroyApp(boolean unconditional) {}

  public void exitMIDlet() {
    destroyApp(true);
    notifyDestroyed();
  }
}
class LinesTimerTask extends TimerTask
{
  private ScreenSaverCanvas canvas;
  private Random random;

  public LinesTimerTask(ScreenSaverCanvas canvas)
  {
    random = new java.util.Random();
    this.canvas = canvas;
  }

  /*--------------------------------------------------
  *决定下一个划线的结束点
  *-------------------------------------------------*/
  public final void run()
  {
    //得到随机的x,y坐标值,确保是在画布范围内的值
    canvas.endx = (random.nextInt() >>> 1) % canvas.getWidth();
    canvas.endy = (random.nextInt() >>> 1) % canvas.getHeight();
    //记录已经划的线条
    canvas.linesDrawn++;
    canvas.repaint();
  }
}