我有一个脚本，当你点击箭头时，第二个项目变得可见，第一个变为不可见，这继续4个项目，然后在第四个项目返回到第一个项目等。代码不这样做但是，在第一次点击时，第一个项目仍然存在，在第二次点击时，第三个和第一个项目仍然可见，在第四个第四个项目，第一个是可见的，然后在第四次点击后一切正常。有人可以帮我解决这个问题吗？
getting_started.alpha = 1;
building_your_site.alpha = 0;
web_enhancement.alpha = 0;
site_maintenance.alpha = 0;
leftArrow_mc.addEventListener(MouseEvent.CLICK, rotateLeft);
function rotateLeft(event: MouseEvent):void
{
if (bottomWheel_menu_mc.rotation == 0)
{
TweenLite.to(getting_started, 1, {alpha:0});
TweenLite.to(site_maintenance, 1, {alpha:1});
}
else if (bottomWheel_menu_mc.rotation == 90)
{
TweenLite.to(site_maintenance, 1, {alpha:0});
TweenLite.to(web_enhancement, 1, {alpha:1});
}
else if (bottomWheel_menu_mc.rotation == 180)
{
TweenLite.to(web_enhancement, 1, {alpha:0});
TweenLite.to(building_your_site, 1, {alpha:1});
}
else if (bottomWheel_menu_mc.rotation == -90)
{
TweenLite.to(building_your_site, 1, {alpha:0});
TweenLite.to(getting_started, 1, {alpha:1});
}
else if (bottomWheel_menu_mc.rotation == -180)
{
TweenLite.to(web_enhancement, 1, {alpha:0});
TweenLite.to(building_your_site, 1, {alpha:1});
}
}