CLASSES - Flash Advertising - page 229

public static function play(targetClip:MovieClip,
loopCount:int=0, targetFrame:int=1, speed:Number=30):void {
if(!_revTimer.hasEventListener(TimerEvent.TIMER)){
_targetClip = targetClip;
_targetFrame = targetFrame;
_loopCount = loopCount;
_revTimer.delay = speed;
_revTimer.addEventListener(TimerEvent.TIMER,
reverseFrame, false, 0, true);
}
_revTimer.start();

}

The reverseFrame method that gets called as a result of _revTimer
firing off a TimerEvent makes a simple decision to either move the
MovieClip back by one frame or not. So, first it compares the
currentFrame property of _targetClip to the value of _targetFrame .
If _targetClip hasn ' '

t reached that point on the timeline yet, we ll

tell it to go backwards by one frame ( prevFrame ). Remember, we re

testing to see if currentFrame is greater than _targetFrame because
the MovieClip is playing backwards at this point. So if it

'

s
not greater, then we need to stop rewinding. The first thing to do in
this case is to force the MovieClip to gotoAndStop(_targetFrame) .
This step is really just a fallback to make sure the timeline didn

'

' tgo

too far. Since we re accounting for

the possibility that the playhead reversed too far by at least one
frame. Next, we

' re forcing the frame number, we '

ll reset the timer, so it will be ready to go when/if
we need it again. At the end of this piece, let

'

' schecktoseeif _loop

Count is equal to ‒ 1 (remember, that means infinite looping). If it is

equal to 1, all we need to do is tell _targetClip to play again. On

the other hand, if _loopCount is not equal to

‒

‒ 1, we ' ll call the replay

method.

private static function reverseFrame(e:TimerEvent):void {
if(_targetClip.currentFrame > _targetFrame){
_targetClip.prevFrame();
}else{
_targetClip.gotoAndStop(_targetFrame);
_revTimer.reset();
_loopCount==

‒ 1 ? _targetClip.play() : replay();

}

}

And now for the replay method. The replay method also
consists of a pretty simple if/else statement. Our test this time is to
see if _currentLoop is less than _loopCount . If it is, we increase
_currentLoop and tell _targetClip to play again (or loop).
If _currentLoop is not less than _loopCount ,it ' s time to stop