gistfile1.m

// Transition duration between changing content view controllers
// Default: 0.0
@property (nonatomic, assign) NSTimeInterval contentViewControllerAnimationDuration;

// Animation option for setting content view controller
// Default: 0
@property (nonatomic, assign) NSInteger contentViewControllerAnimationOption;



- (void)setContentViewController:(UIViewController *)contentViewController snapToContentViewController:(BOOL)snapToContentViewController animated:(BOOL)animated
{

            [self transitionFromViewController:currentContentViewController toViewController:[self contentViewController] duration:[self contentViewControllerAnimationDuration] options:[self contentViewControllerAnimationOption] animations:nil completion:^