actionscript-3 - AS3 获取当前时间而不创建新对象

Question

如何在不使用“新”运算符的情况下在 AS3 中获取自 1970 年 1 月 1 日午夜以来的当前毫秒数？我问是因为我需要每秒执行大约 100 次，并且目前尝试减少堆分配以保持 gc 低。

Answer 1

您应该创建一次，然后添加自使用 getTimer() 创建以来经过的毫秒数；您还需要一个帮助变量来存储您的数据创建时间；

package 
{
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.utils.getTimer;

    public class Main extends Sprite 
    {
        private var _myLittleDate:Date;
        private var _myLittleDateCreationTime:Number;

        public function Main():void 
        {
            _myLittleDate = new Date(); //Our first and only object creation
            _myLittleDateCreationTime = getTimer(); //Store it's creation time
            addEventListener(Event.ENTER_FRAME, onEnterFrame); //Check function
        }

        private function onEnterFrame(e:Event):void 
        {
            _myLittleDate.time += ( getTimer() - _myLittleDateCreationTime );
            trace(_myLittleDate); //You get valid, refreshed data object here
            _myLittleDateCreationTime = getTimer(); // Don't forget to update your initial time
            //It's accurate since method .getTimer() is accurate itself
            //You can even compare two Data object by creating another and tracing it right here
        }
    }
}

如果您只需要知道自上一帧以来经过了多少时间，而不知道星期几或一年，您可以使用 getTimer(); 自己做，效率更高

Answer 2

我使用的实用方法：

// Get time since the epoch and time since the VM was started
private static const dateTime:Number = new Date().time;
private static const dateTimestamp:uint = getTimer();
/**
 * Current time in ms
 */ 
public static function getCurrentTime():Number
{
    return dateTime + (getTimer() - dateTimestamp);
}