Animate table view deselection alongside interactive transition on iOS 11

InteractiveTransitionTableViewDeselection.m

/*
In iOS 11, interactive view controller transitions no longer scrub by setting the layer speed to zero
and changing the timeOffset. As a result of this change, implicit animations that occur in places like
-viewWillAppear: (called during an interactive transition) no longer end up “caught in” the animation.

To get the same behavior for table view row deselection as before, you can either use UITableViewController
which implements this for you, or you can implement it manually by deselecting the row in an alongside
animation for the transition (set up in -viewWillAppear: using the transition coordinator).

Here is an example implementation which correctly handles some of the more subtle corner cases:
*/

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    
    NSIndexPath *selectedIndexPath = [self.tableView indexPathForSelectedRow];
    if (selectedIndexPath != nil) {
        id<UIViewControllerTransitionCoordinator> coordinator = self.transitionCoordinator;
        if (coordinator != nil) {
            [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {
                [self.tableView deselectRowAtIndexPath:selectedIndexPath animated:YES];
            } completion:^(id<UIViewControllerTransitionCoordinatorContext> context) {
                if (context.cancelled) {
                    [self.tableView selectRowAtIndexPath:selectedIndexPath animated:NO scrollPosition:UITableViewScrollPositionNone];
                }
            }];
        } else {
            [self.tableView deselectRowAtIndexPath:selectedIndexPath animated:animated];
        }
    }
}