// Curl the image up or down
CATransition *animation = [CATransition animation];
[animation setDuration:0.35];
[animation setTimingFunction:UIViewAnimationCurveEaseInOut];
if (!curled){
//animation.type = @"mapCurl";
animation.type = @"pageCurl";
animation.fillMode = kCAFillModeForwards;
animation.endProgress = 0.5;
} else {
//animation.type = @"mapUnCurl";
animation.type = @"pageUnCurl";
animation.fillMode = kCAFillModeBackwards;
animation.startProgress = 0.5;
}
[animation setRemovedOnCompletion:NO];
[self.view exchangeSubviewAtIndex:0 withSubviewAtIndex:1];
[self.view.layer addAnimation:animation forKey :@"pageCurlAnimation"];
// Disable user interaction where necessary
if (!curled) {
} else {
}
curled = !curled;
// Do any additional setup after loading the view, typically from a nib.
原文：http://www.cnblogs.com/isItOk/p/4875718.html