Flash I'；我是AS 3.0编程新手，我希望为键盘控件创建一个随机发生器

我正试图为我的课程编写一个随机生成器，用于控制，游戏是一个版本的太空入侵者，但游戏将包括每10秒随机一次的控制，并且会在5秒内改变。我拥有的代码

package  
{
    import flash.display.MovieClip;
    import flash.events.*;
    import flash.utils.Timer;
    import flash.events.KeyboardEvent;
    import flash.events.TimerEvent



    public class Main extends MovieClip {
        var leftPressed:Boolean = false;
        var rightPressed:Boolean = false;
        var bullet 
        var myTimer:Timer = new Timer (10000, 90)
        //initaialises the variables by setting them to false

        public function Main() 
        {
            // constructor code
            Spaceship.addEventListener(Event.ENTER_FRAME, moveToKey);
            stage.addEventListener(KeyboardEvent.KEY_DOWN, whichKey);
            stage.addEventListener(KeyboardEvent.KEY_UP, setKeyUnPres);
        }   //adds an evernt listener that will check for any key presses



        function whichKey(e:KeyboardEvent)
        {       // these are the key codes for the keys that will be pressed
                    // it also checks for if the key code is pressed 

            if (e.keyCode == 37)
            {       // that is left
                leftPressed = true;
                    // that sets the variable to true
                    //stating that it only has two conditions
                    // leads to a condition later, on line 54 
            }
            if (e.keyCode == 39)
            {       // that is right
                    // performss the exact same task as the one above
                    // leads to a condition later, on line 59
                rightPressed = true;
            }

                    // both of the funtions are triggered by pressing the 
                    //keys on your keyboard.
                    // the one above is triggered when you press the keys
                    //the one beneath is triggered when the key is pressed
        }

        function setKeyUnPres(e: KeyboardEvent)
        {       // function sets the variable to false, meaning that it doesn't activate
                //these functions are only trigged when the key is pressed down
            if (e.keyCode == 37)
            {       
                leftPressed = false;
            }
            if (e.keyCode == 39)
            {
                rightPressed = false;
            }
        }

        function moveToKey (e:Event)
        {       // these function is run if both of the statements are run.

            // this is true for both conditions listed
            if (leftPressed && (Spaceship.x>0))
                // this function makes the Spaceship move 5 pixels to the left
            // when the variable leftPressed is true and the spaceship is greater than 0 pixels
            // the function will run
            {   
                Spaceship.x -= 5;

            }
            if (rightPressed && (Spaceship.x<550))
                // this function makes the Spaceship move 5 pixels to the right 
            // when the variable rightPressed is true and the shapscehip is less than 550 pixels
            // the function will run
            {
                Spaceship.x += 5;
            }
            if (e.keyCode == 32) {
                var bulletshot:bullet = new bullet();
                addChild(bulletshot);
                bulletshot.x = Spaceship.x;
                bulletshot.y = Spaceship.y;
            }

        }
    }
}

包
{
导入flash.display.MovieClip；
导入flash.events.*；
导入flash.utils.Timer；
导入flash.events.KeyboardEvent；
导入flash.events.TimerEvent
公共类Main扩展了MovieClip{
var leftPressed:Boolean=false；
var rightPressed:Boolean=false；
var子弹
var myTimer:Timer=新定时器（10000，90）
//通过将变量设置为false来初始化变量
公共功能Main（）
{
//构造代码
Spaceship.addEventListener（Event.ENTER_FRAME，moveToKey）；
stage.addEventListener（KeyboardEvent.KEY\u DOWN，whichKey）；
stage.addEventListener（KeyboardEvent.KEY\u UP，setkeyunpos）；
}//添加一个evernt侦听器，该侦听器将检查是否有任何按键
按键功能（e：键盘事件）
{//这些是将要按下的键的键代码
//它还检查是否按下了键代码
如果（e.keyCode==37）
{//就剩这个了
leftPressed=true；
//这将变量设置为true
//声明它只有两个条件
//随后在第54行导致一种情况
}
如果（e.keyCode==39）
{//没错
//执行与上述任务完全相同的任务
//随后在第59行导致一种情况
rightspressed=true；
}
//这两种功能都是通过按下
//键盘上的按键。
//当您按键时，会触发上面的一个
//按下该键时会触发下面的一个
}
函数SetKeyUnpus（e:键盘事件）
{//函数将变量设置为false，这意味着它不会激活
//这些功能仅在按键时触发
如果（e.keyCode==37）
{       
leftPressed=false；
}
如果（e.keyCode==39）
{
右压=假；
}
}
函数moveToKey（e:事件）
{//如果两条语句都运行，则这些函数将运行。
//对于列出的两种情况都是如此
如果（左键按下&（Spaceship.x>0））
//此功能使宇宙飞船向左移动5个像素
//当变量leftPressed为true且宇宙飞船大于0像素时
//该函数将运行
{   
宇宙飞船.x-=5；
}
如果（右）按下&（Spaceship.x