react-native-navigation/lib/ios/ElementTransitionsCreator.m

#import "ElementTransitionsCreator.h"
#import "RNNElementFinder.h"

@implementation ElementTransitionsCreator

+ (NSArray<DisplayLinkAnimatorDelegate> *)create:(NSArray<ElementTransitionOptions *> *)elementTransitions fromVC:(UIViewController *)fromVC toVC:(UIViewController *)toVC containerView:(UIView *)containerView {
    NSMutableArray<DisplayLinkAnimatorDelegate>* transitions = [NSMutableArray<DisplayLinkAnimatorDelegate> new];
    for (ElementTransitionOptions* transitionOptions in elementTransitions) {
        UIView* element = [self findElementById:transitionOptions.elementId fromVC:fromVC toVC:toVC];
        ElementAnimator* elementAnimator = [[ElementAnimator alloc] initWithTransitionOptions:transitionOptions
                                                                                         view:element
                                                                                       fromVC:fromVC
                                                                                         toVC:toVC
                                                                                containerView:containerView];
        [transitions addObject:elementAnimator];
    }
    
    return transitions;
}

+ (id<DisplayLinkAnimatorDelegate>)createTransition:(ElementTransitionOptions *)transitionOptions view:(UIView *)view fromVC:(UIViewController *)fromVC toVC:(UIViewController *)toVC containerView:(UIView *)containerView {
    ElementAnimator* elementAnimator = [[ElementAnimator alloc] initWithTransitionOptions:transitionOptions
                                                                                     view:view
                                                                                   fromVC:fromVC
                                                                                     toVC:toVC
                                                                            containerView:containerView];
    
    return elementAnimator;
}

+ (UIView *)findElementById:(NSString *)elementId fromVC:(UIViewController *)fromVC toVC:(UIViewController *)toVC {
    UIView* viewInSourceView = [RNNElementFinder findElementForId:elementId inView:fromVC.view];
    if (viewInSourceView) {
        return viewInSourceView;
    }
    
    UIView* viewInDestinationView = [RNNElementFinder findElementForId:elementId inView:toVC.view];
    if (viewInDestinationView) {
        return viewInDestinationView;
    }
    
    return nil;
}

@end