snippet.m

NS_INLINE void MLSwizzleMethod(Class c, SEL original, SEL alternate) {
    Method origMethod = class_getInstanceMethod(c, original);
    Method newMethod = class_getInstanceMethod(c, alternate);
    
    if(class_addMethod(c, original, method_getImplementation(newMethod), method_getTypeEncoding(newMethod))) {
        class_replaceMethod(c, alternate, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
    } else {
        method_exchangeImplementations(origMethod, newMethod);
    }
}

/**
 *  Workaround to prevent VO from accessing elements in presenting view beneath overlay.
 *
 *  @param transitionView UIPresentationController.containerView
 */

static void *MLTransitionViewPatchIsModalAssociatedKey = &MLTransitionViewPatchIsModalAssociatedKey;

@interface UIView (MLTransitionViewAccessibilityPatch) @end
@implementation UIView (MLTransitionViewAccessibilityPatch)

+ (void)initialize {
    Class cls_ = NSClassFromString([@[ @"UI", @"Transition", @"View" ] componentsJoinedByString:@""]);
    
    if(self == cls_) {
        static dispatch_once_t onceToken;
        dispatch_once(&onceToken, ^{
            MLSwizzleMethod(self, @selector(accessibilityViewIsModal), @selector(ml_transitionView_accessibilityViewIsModal));
        });
    }
}

- (void)ml_transitionView_setAccessibilityViewIsModal:(BOOL)isModal {
    objc_setAssociatedObject(self, MLTransitionViewPatchIsModalAssociatedKey, @(isModal), OBJC_ASSOCIATION_COPY);
}

- (BOOL)ml_transitionView_accessibilityViewIsModal {
    NSNumber *number = objc_getAssociatedObject(self, MLTransitionViewPatchIsModalAssociatedKey);
    
    BOOL superValue = [self ml_transitionView_accessibilityViewIsModal];
    
    return number ? [number boolValue] : superValue;
}

@end

void MLPatchTransitionViewAccessibility(UIView *transitionView, BOOL shouldBeModal) {
    NSCParameterAssert(transitionView);
    
    [transitionView ml_transitionView_setAccessibilityViewIsModal:shouldBeModal];
}