Flex中多线程的实现

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Flex中多线程的实现

最近在网上看到一个工具类可以提供flex中多线程的支持，AsyncThreading，googleCode地址　　 （【AsyncThreading_2[1].1.zip】下载地址），详细文档可以去googleCode上看

下面总结一下利用这个工具类来实现一个抽奖机的demo。
首先我们要编写一个自定义线程类，继承自AbstractAsyncThread并且实现IAsyncThreadResponder接口，
AbstractAsyncThread这个类可以控制线程的级别：
                 public const RUN_LEVEL_REAL_TIME:int = 1;
                public const RUN_LEVEL_HIGH:int = 3;
                public const RUN_LEVEL_ABOVE_NORMAL:int = 6:
                public const RUN_LEVEL_NORMAL:int = 8;
                public const RUN_LEVEL_BELOW_NORMAL:int = 12:
                public const RUN_LEVEL_LOW:int = 24;  

IAsyncThreadResponder这个接口提供了一个线程启动后调用的方法
                 function execute():void;

自定义线程对象类代码如下：
package threads
{
        import cn.ningyu.utils.Random;
       
        import com.symantec.premiumServices.asyncThreading.abstract.AbstractAsyncThread;
        import com.symantec.premiumServices.asyncThreading.interfaces.IAsyncThreadResponder;
       
        import mx.controls.Label;
        public class WorkBee extends AbstractAsyncThread implements IAsyncThreadResponder
        {
                private var _lab:Label;
                public function WorkBee(lab:Label)
                {
                        _lab = lab;
                        super();
                        super.priority = super.RUN_LEVEL_REAL_TIME;
                }
               
                public function execute():void
                {
                        var random:Random = Random.getInstance();
                        random.digit = 1;
                        random.radix = Random.NUMBER;
                        _lab.text = random.createRandom();
                }
               
        }
}

application中代码如下：
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" creationComplete="init()">
       
        <mx:Script>
                <![CDATA[
                        import threads.WorkBee;
                        import com.symantec.premiumServices.asyncThreading.AsyncThreadingManager;
                        import mx.collections.ArrayCollection;
                       
                        private var threadList:ArrayCollection = new ArrayCollection();
               
                        private function init():void {
                                threadList = new ArrayCollection();
                                for(var i:int=0;i<7;i++) {
                                        var workBee:WorkBee;
                                        switch(i) {
                                                case 0:
                                                        workBee = new WorkBee(lab1);
                                                        break;
                                                case 1:
                                                        workBee = new WorkBee(lab2);
                                                        break;
                                                case 2:
                                                        workBee = new WorkBee(lab3);
                                                        break;
                                                case 3:
                                                        workBee = new WorkBee(lab4);
                                                        break;
                                                case 4:
                                                        workBee = new WorkBee(lab5);
                                                        break;
                                                case 5:
                                                        workBee = new WorkBee(lab6);
                                                        break;
                                                case 6:
                                                        workBee = new WorkBee(lab7);
                                                        workBee.wake()
                                                        break;
                                        }
                                        threadList.addItem(workBee);
                                }
                        }
                       
                        private function onClick():void {
                                if(btn.label == "开始抽奖") {
                                        for(var i:int=0;i<7;i++) {
                                                if(threadList[i].sleeping) {
                                                        threadList[i].wake();
                                                } else {
                                                        threadList[i].start();
                                                }
                                        }
                                        btn.label = "停止抽奖";
                                } else if(btn.label == "停止抽奖") {
                                        for(var i:int=0;i<7;i++) {
                                                threadList[i].sleep();
                                        }
                                        btn.label = "开始抽奖";
                                }
                        }
                       
                ]]>
        </mx:Script>
       
        <mx:FormItem verticalCenter="0" horizontalCenter="0" direction="horizontal" fontSize="50" fontWeight="bold">
                <mx:Label id="lab1"/>
                <mx:Label id="lab2"/>
                <mx:Label id="lab3"/>
                <mx:Label id="lab4"/>
                <mx:Label id="lab5"/>
                <mx:Label id="lab6"/>
                <mx:Label id="lab7"/>
                <mx:Button id="btn" label="开始抽奖" click="onClick()"/>
        </mx:FormItem>
</mx:Application>

注意的点：
线程方法：start()启动线程
          sleep()休眠线程
          sleeping线程是否处在休眠状态
          wake()重新激活线程
          kill()杀掉线程
async-threading 
还提供AsyncThreadingManager来管理所有的进程
提供的方法：
           shutDown()停掉所有的线程
           killAllThreads()杀掉所有的线程
还支持线程之间通信，利用sendMessageToThreads(name:String,body:Object):Boolean
将其中的代码移植到 Flex4的项目中 在创建线程的时候 报错
TypeError: Error #1009: Cannot access a property or method of a null object reference.
解决办法：
下载 AsyncThreading_2.1 源码到本地，修改 com.symantec.premiumServices.asyncThreading.handlers.FPSObserverHandler 中的代码 如下：
import mx.core.Application;
修改为：
import spark.components.Application;
private var _appRef:Application = Application.applicationas Application;
修改为：
private var _appRef:Application = FlexGlobals.topLevelApplication as Application;
OK 完成 错误解决！