之四：CATransition

关键属性：

• type 过渡效果 

1. kCATransitionFade  淡出  
2. kCATransitionMoveIn  覆盖原图  
3. kCATransitionPush  推出  
4. kCATransitionReveal  底部显出来  

• subtype 过渡方向

1. kCATransitionFromRight；
2. kCATransitionFromLeft  默认值  
3. kCATransitionFromTop；  
4. kCATransitionFromBottom  

代码演示1：不用setSubtype，只用setType

animation.type=@"pageCurl";  

pageCurl   向上翻一页
pageUnCurl   向下翻一页
rippleEffect   滴水效果
suckEffect   收缩效果，如一块布被抽走
cube   立方体效果
oglFlip   上下翻转效果

代码演示2：setType与setSubtype组合

CATransition *animation = [CATransition animation];

animation.delegate = self;

animation.duration = 1.0f;

animation.timingFunction = UIViewAnimationCurveEaseInOut;

animation.type = kCATransitionMoveIn;

animation.subtype = kCATransitionFromTop;

[_myView.layer addAnimation:animation forKey:@"myTransition"];