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];