Question

flash as3 怎样让元件一开始向一个随机的方向，然后在这个方向上按照同样的速度移动

Answer 1

在影片剪辑的帧上加如下代码即可：
var speed:Number=5;//移动速度
this.rotation=360*Math.random();//随机移动方向
this.addEventListener(Event.ENTER_FRAME,MoveEvent);
function MoveEvent(e:Event):void
{
var obj:Object=e.target;
obj.x+=Math.sin(obj.rotation)*speed;
obj.y+=Math.cos(obj.rotation)*speed;
}

追问

那碰到边界反弹，还是一样的速度，怎么做？

追答

看看这个效果吧。。。

Answer 2

创建一个元件放在舞台中，起实例名为mc
speedx = -(random(10))+5;
speedy = -(random(10))+5;
onEnterFrame = function () {
speed = -(random(10))+5;
trace(speed);
mc._x += speedx;
mc._y += speedy;
};

追问

speed是干什么用的？

追答

没用，刚才用来测试的，4,5行都可以删除掉不要

追问

那碰到边界反弹，还是一样的速度，怎么做？

Answer 3

//命名一个影片剪辑实例名为xiaoqiu
var speed=10;//初速度
var zbj = 0;
var ybj =stage.stageWidth;
var sbj = 0;
var xbj =stage.stageHeight
var vx=(Math.random()-Math.random())*speed//小球x轴速度方向
var vy = (Math.random()-Math.random())*speed//小球y轴速度方向
addEventListener(Event.ENTER_FRAME,MoveEvent);
function MoveEvent(e:Event):void
{

xiaoqiu.x += vx;
xiaoqiu.y += vy;
if (xiaoqiu.x - xiaoqiu.width / 2 <= zbj || xiaoqiu.x + xiaoqiu.width / 2 >= ybj)
{
if (xiaoqiu.x - xiaoqiu.width / 2 <= zbj)
{
xiaoqiu.x = 0 + xiaoqiu.width / 2;
vx *= -1;

}
else
{
xiaoqiu.x = ybj - xiaoqiu.width / 2;
vx *= -1;
}

}//x轴边界判断
else if (xiaoqiu.y - xiaoqiu.height / 2 <= sbj || xiaoqiu.y + xiaoqiu.height / 2 >= xbj)
{
if (xiaoqiu.y - xiaoqiu.height / 2 <= sbj)
{
xiaoqiu.y = 0 + xiaoqiu.height / 2;
vy *= -1;
}
else
{
xiaoqiu.y = xbj - xiaoqiu.height / 2;
vy *= -1;
}
}//y轴边界判断

}
/**
*以下是小球运动中的物理现象
*
*
*
*
*
*
**/
//命名一个影片剪辑实例名为xiaoqiu
var speed=10;//初速度
var zbj = 0;
var ybj =stage.stageWidth;
var sbj = 0;
var xbj =stage.stageHeight
var vx=(Math.random()-Math.random())*speed//小球x轴速度方向
var vy = (Math.random()-Math.random())*speed//小球y轴速度方向
addEventListener(Event.ENTER_FRAME,MoveEvent);
function MoveEvent(e:Event):void
{
vy+=0.1
xiaoqiu.x += vx;
xiaoqiu.y += vy;
trace(vx)
if (xiaoqiu.x - xiaoqiu.width / 2 <= zbj || xiaoqiu.x + xiaoqiu.width / 2 >= ybj)
{
if (xiaoqiu.x - xiaoqiu.width / 2 <= zbj)
{
xiaoqiu.x = 0 + xiaoqiu.width / 2;
vx *= -1

}
else
{
xiaoqiu.x = ybj - xiaoqiu.width / 2;
vx *= -1;
}

}//x轴边界判断
else if (xiaoqiu.y - xiaoqiu.height / 2 <= sbj || xiaoqiu.y + xiaoqiu.height / 2 >= xbj)
{
if (xiaoqiu.y - xiaoqiu.height / 2 <= sbj)
{
xiaoqiu.y = 0 + xiaoqiu.height / 2;
vy *= -1;
}
else
{
xiaoqiu.y = xbj - xiaoqiu.height / 2;
vy *= -0.54;
vx*=0.78
if(vx*vx-0.000000000001<=0)
{ vy=0;
vx=0
removeEventListener(Event.ENTER_FRAME,MoveEvent);
}
}
}//y轴边界判断

}
//不懂的可以提问在线解答

Answer 4

要写AS代码的！我忘记怎么写了！上网搜一下应该有