レイヤーとそのサブレイヤーのアニメーションをチェーンしようとしています。ただし、私が抱えている問題は、アニメーションのサブレイヤーの位置のモデル更新が、スーパーレイヤーのアニメーション中に視覚的に明らかになることです。アニメーションをチェーンするために使用しているコードは次のとおりです。
// Superlayer.
CFTimeInterval now = [self.artworkContainer.layer convertTime:CACurrentMediaTime() fromLayer:nil];
CABasicAnimation *slideDown = [CABasicAnimation animationWithKeyPath:@"position"];
slideDown.duration = SLIDE_DOWN_DURATION; //SLIDE_DOWN_DURATION;
slideDown.beginTime = now;
slideDown.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
slideDown.fromValue = [self.artworkContainer.layer valueForKey:@"position"];
CGPoint finalPointOfContainer = CGPointMake(self.artworkContainer.layer.position.x, self.artworkContainer.layer.position.y+verticalDistanceOfFirstFall);
slideDown.toValue = [NSValue valueWithCGPoint:finalPointOfContainer];
self.artworkContainer.layer.position = finalPointOfContainer;
[self.artworkContainer.layer addAnimation:slideDown forKey:@"position"];
// Sublayer
CABasicAnimation *moveActualArtwork = [CABasicAnimation animationWithKeyPath:@"position"];
moveActualArtwork.duration = timeOfSecondFall;
moveActualArtwork.beginTime = now + SLIDE_DOWN_DURATION;
moveActualArtwork.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
moveActualArtwork.fromValue = [self.artWork.layer valueForKey:@"position"];
CGPoint finalPointOfArtwork = CGPointMake(self.artWork.layer.position.x, self.artWork.layer.position.y+verticalDistanceOfSecondFall);
moveActualArtwork.toValue = [NSValue valueWithCGPoint:finalPointOfArtwork];
self.artWork.layer.position = finalPointOfArtwork; // If this is commented out, the superlayer animation looks correct (of course this isn't a true fix because the sublayer snaps back to its original position without a model update).
moveActualArtwork.delegate = self;
[self.artWork.layer addAnimation:moveActualArtwork forKey:@"position"];