前面的博客有对cocoachina上一篇动画的文章做过简单的说明，我们所看到的各种动画其实就是动画的组合，把不同的动画组合起来就成了很多我们认为高大上的效果，看下图，边移动变换颜色：
其中沿贝赛尔曲线运动是一个运动轨迹的动画（叫做关键帧动画，前面有单篇博客专门说关键帧动画），变换颜色是另一个基础动画，通过CAAnimationGroup就让它们同时执行，下面看代码：
UIBezierPath *bezierPath = [[UIBezierPath alloc] init]; [bezierPath moveToPoint:CGPointMake(0, 150)]; [bezierPath addCurveToPoint:CGPointMake(300, 150) controlPoint1:CGPointMake(75, 0) controlPoint2:CGPointMake(170, 450) ]; //draw the path using a CAShapeLayer CAShapeLayer *pathLayer = [CAShapeLayer layer]; pathLayer.path = bezierPath.CGPath; pathLayer.fillColor = [UIColor clearColor].CGColor; pathLayer.strokeColor = [UIColor redColor].CGColor; pathLayer.lineWidth = 3.0f; [self.containerView.layer addSublayer:pathLayer]; //add a colored layer CALayer *colorLayer = [CALayer layer]; colorLayer.frame = CGRectMake(0, 0, 64, 64); colorLayer.position = CGPointMake(0, 150); colorLayer.backgroundColor = [UIColor greenColor].CGColor; [self.containerView.layer addSublayer:colorLayer]; //create the position animation CAKeyframeAnimation *animation1 = [CAKeyframeAnimation animation]; animation1.keyPath = @"position"; animation1.path = bezierPath.CGPath; animation1.rotationMode = kCAAnimationRotateAuto; //create the color animation CABasicAnimation *animation2 = [CABasicAnimation animation]; animation2.keyPath = @"backgroundColor"; animation2.toValue = (__bridge id)[UIColor redColor].CGColor; //create group animation CAAnimationGroup *groupAnimation = [CAAnimationGroup animation]; groupAnimation.animations = @[animation1, animation2]; groupAnimation.duration = 4.0; //add the animation to the color layer [colorLayer addAnimation:groupAnimation forKey:nil];
这里是对组动画的简单运用，还有很多的组合方式，想要实现炫酷的动画效果，理解了组动画和绘图技巧后就足以动手自己随意组合了。
