1、我们是使用Core Animatioin创建动画的时，实质上是更改CALayer的属性，然后让这些属性流畅的变化。可以使用Core Animation对象的位置、颜色、透明度以及CGAffine变换来制作动画。

2、一个简单的小动画

/隐式动画/

- (void)viewDidLoad {

[super viewDidLoad];

UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 40, 40)];

[UIView beginAnimations:nil context:NULL];

[UIView setAnimationDuration:2.0];  //设置动画时长

CGAffineTransform moveTransform = CGAffineTransformMakeTranslation(200, 300);  //移动到固定的位置

[imageView.layer setAffineTransform:moveTransform];

imageView.layer.opacity = 1;

[UIView commitAnimations];

imageView.backgroundColor = [UIColor redColor];

[self.view addSubview:imageView];

}

/显示动画/

- (void)viewDidLoad {

[super viewDidLoad];

UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 40, 40)];

imageView.backgroundColor = [UIColor redColor];

CABasicAnimation *opAnim = [CABasicAnimation animationWithKeyPath:@"opacity"];

opAnim.duration = 3.0;

//定义开始和结束的透明度

opAnim.fromValue = [NSNumber numberWithFloat:1.0];

opAnim.toValue = [NSNumber numberWithFloat:0];

opAnim.cumulative = YES;

opAnim.repeatCount = 6;    //重复次数

[imageView.layer addAnimation:opAnim forKey:@"animateOpacity"];

CGAffineTransform moveTransform = CGAffineTransformMakeTranslation(200, 300);

CABasicAnimation *moveAnim = [CABasicAnimation animationWithKeyPath:@"transform"];

moveAnim.duration = 6.0;

moveAnim.toValue = [NSValue valueWithCATransform3D:CATransform3DMakeAffineTransform(moveTransform)];

[imageView.layer addAnimation:moveAnim forKey:@"animateTransform"];

[self.view addSubview:imageView];