popAnimation like UIAlertView. via http://xcodev.com/761.html

popAnimation

CAKeyframeAnimation *popAnimation = [CAKeyframeAnimation animationWithKeyPath:@"transform"];
popAnimation.duration = 0.4;
popAnimation.values = @[[NSValue valueWithCATransform3D:CATransform3DMakeScale(0.01f, 0.01f, 1.0f)],
                        [NSValue valueWithCATransform3D:CATransform3DMakeScale(1.1f, 1.1f, 1.0f)],
                        [NSValue valueWithCATransform3D:CATransform3DMakeScale(0.9f, 0.9f, 1.0f)],
                        [NSValue valueWithCATransform3D:CATransform3DIdentity]];
popAnimation.keyTimes = @[@0.0f, @0.5f, @0.75f, @1.0f];
popAnimation.timingFunctions = @[[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut],
                                 [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut],
                                 [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
[anAlertAnimationView.layer addAnimation:popAnimation forKey:nil];