Custom Push in/out Transition Animation for Modal View Controllers

Implementing a custom transition animation for view controllers is not too difficult. Let's consider that we need to push from right/left when presenting a modal view controller, and then pushing out to the other direction when dismissing the dialog. The below mentioned UIViewController category serves this purpose for us.

@interface UIViewController (Transitions)

- (void) presentModalViewController:(UIViewController *)modalViewController withPushDirection: (NSString *) direction;
- (void) dismissModalViewControllerWithPushDirection:(NSString *) direction;

@end  

and the implementation:

#import "UIViewController+Transitions.h"

@implementation UIViewController (Transitions)

- (void) presentModalViewController:(UIViewController *)modalViewController withPushDirection: (NSString *) direction {
    
    [CATransaction begin];
    
    CATransition *transition = [CATransition animation];
    transition.type = kCATransitionPush;
    transition.subtype = direction;
    transition.duration = 0.25f;
    transition.fillMode = kCAFillModeForwards;
    transition.removedOnCompletion = YES;
    
    [[UIApplication sharedApplication].keyWindow.layer addAnimation:transition forKey:@"transition"];
    [[UIApplication sharedApplication] beginIgnoringInteractionEvents];
    [CATransaction setCompletionBlock: ^ {
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(transition.duration * NSEC_PER_SEC)), dispatch_get_main_queue(), ^ {
            [[UIApplication sharedApplication] endIgnoringInteractionEvents];
        });
    }];
    
    [self presentViewController:modalViewController animated:NO completion:nil];
    
    [CATransaction commit];
    
}

- (void) dismissModalViewControllerWithPushDirection:(NSString *) direction {
    
    [CATransaction begin];
    
    CATransition *transition = [CATransition animation];
    transition.type = kCATransitionPush;
    transition.subtype = direction;
    transition.duration = 0.25f;
    transition.fillMode = kCAFillModeForwards;
    transition.removedOnCompletion = YES;
    
    [[UIApplication sharedApplication].keyWindow.layer addAnimation:transition forKey:@"transition"];
    [[UIApplication sharedApplication] beginIgnoringInteractionEvents];
    [CATransaction setCompletionBlock: ^ {
        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(transition.duration * NSEC_PER_SEC)), dispatch_get_main_queue(), ^ {
            [[UIApplication sharedApplication] endIgnoringInteractionEvents];
        });
    }];
    
    [self dismissViewControllerAnimated:NO completion:nil];
    
    [CATransaction commit];
    
}

@end

To use it, you import "UIViewController+Transitions.h" in your file and call the presentModalViewController:withPushDirection:

the direction parameter receives core animation transition sub-types such as kCATransitionFromRight.

You can download the category files from here and import to your project.

Enjoy...