[冷枫]J2me多线程

Thread 类

Thread 类是一个具体的类，即不是抽象类，该类封装了线程的行为。要创建一个线程，就必须创建一个继承自

Thread 类子类。程序员必须覆盖Thread 的 run() 函数来完成有用的工作。使用时并不直接调用此函数；而是

必须调用 Thread 的 start() 函数，该函数再调用 run()。下面的代码说明了它的用法：

import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class Bounce extends MIDlet {
private BounceCanvas myCanvas;
/**
* 声明RectThread线程类
*/
private RectThread rectThreads[];
private boolean done = false;
private Display myDisplay;
/**
* repaint锁
*/
private Object repaintLock = new Object();
Bounce() {
myDisplay = Display.getDisplay(this);
myCanvas = new BounceCanvas();
createRectThreads();
}
/*
* 创建四个矩形框
*/
void createRectThreads () {
rectThreads = new RectThread[4];
rectThreads[0] = new RectThread(2, 2, 30, 30, 8, myCanvas);
rectThreads[1] = new RectThread(-2, -2, 40, 40, 4, myCanvas);
rectThreads[2] = new RectThread(-1, -1, 50, 10, 10,myCanvas);
rectThreads[3] = new RectThread(4, 4, 10, 10, 2, myCanvas);
}
/**
* 启动线程
*/
protected void startApp() throws MIDletStateChangeException {
myDisplay.setCurrent(myCanvas);
if (rectThreads == null) {
createRectThreads();
}
for (int i = 0; i < rectThreads.length; i++) {
if (!rectThreads[i].isAlive()) {
rectThreads[i].start();
}
}
}
/**
* 停止线程
*/
protected void pauseApp() {
done = true;
if (rectThreads != null) {
for(int i = 0; i < rectThreads.length; i++) {
rectThreads[i].stopThread();
}
rectThreads = null;
}
}
protected void destroyApp(boolean unconditional) {}
class BounceCanvas extends Canvas {
public static final int BACKGROUND_COLOR = 0xFFFFFF;
public static final int FOREGROUND_COLOR = 0x000000;
public void paint(Graphics g) {
synchronized (g) {
g.setColor(BACKGROUND_COLOR);
g.fillRect(0, 0, getWidth(), getHeight());
if (rectThreads != null) {
for (int i = 0; i < rectThreads.length; i++) {
rectThreads[i].paint(g);
}
}
}
}
}