Question

I have simple object(AnimateTopDown) which animates up-down continuously , and i have several AnimateTopDown objects which animates but there is no sync between all objects animation. In general how to maintain sync between objects? Is there is any way to sync between separate animation blocks?

p.s. I am using UIViewAnimation interface for animating objects.

Answer 1

//mSyncTime can be shared/global variable

-(NSTimeInterval) getStartDelay
{
    NSTimeInterval delay;

    NSTimeInterval oldTime = mSyncTime;
    if(oldTime == 0)
    {
        mSyncTime = [NSDate timeIntervalSinceReferenceDate];
        oldTime = mSyncTime;
    }

    NSTimeInterval timeNow = [NSDate timeIntervalSinceReferenceDate];

    delay = timeNow - oldTime;

    SLint delayInMiliSec = delay * 1000;
    SLint animDuration = (DEFAULT_ANIM_SPPED*2) * 1000;

    SLint timeElapsed = delayInMiliSec%animDuration;
    delay = animDuration - timeElapsed;

    delay = delay/1000.0;

    if(oldTime == 0)
        delay = 0;

    return delay;
}

And before starting animation I have set the delay to the setAnimationDelay API…

[UIView setAnimationDelay:[self getStartDelay]];

It worked for me… The hack is we have to maintain a standard time and before starting any animation we need to sync our animation to that reference time.