Last active
January 15, 2023 13:03
-
-
Save smileyborg/ec4812c146f575cd006d98d681108ba8 to your computer and use it in GitHub Desktop.
Animate table & collection view deselection alongside interactive transition (for iOS 11 and later)
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Starting 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). | |
The example implementations here correctly handle some of the more subtle corner cases. |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// UICollectionView Objective-C example | |
- (void)viewWillAppear:(BOOL)animated { | |
[super viewWillAppear:animated]; | |
NSIndexPath *selectedIndexPath = [[self.collectionView indexPathsForSelectedItems] firstObject]; | |
if (selectedIndexPath != nil) { | |
id<UIViewControllerTransitionCoordinator> coordinator = self.transitionCoordinator; | |
if (coordinator != nil) { | |
[coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) { | |
[self.collectionView deselectItemAtIndexPath:selectedIndexPath animated:YES]; | |
} completion:^(id<UIViewControllerTransitionCoordinatorContext> context) { | |
if (context.cancelled) { | |
[self.collectionView selectItemAtIndexPath:selectedIndexPath animated:NO scrollPosition:UICollectionViewScrollPositionNone]; | |
} | |
}]; | |
} else { | |
[self.collectionView deselectItemAtIndexPath:selectedIndexPath animated:animated]; | |
} | |
} | |
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// UICollectionView Swift example | |
override func viewWillAppear(_ animated: Bool) { | |
super.viewWillAppear(animated) | |
if let indexPath = collectionView.indexPathsForSelectedItems?.first { | |
if let coordinator = transitionCoordinator { | |
coordinator.animate(alongsideTransition: { _ in | |
self.collectionView.deselectItem(at: indexPath, animated: true) | |
}, completion: { context in | |
if context.isCancelled { | |
self.collectionView.selectItem(at: indexPath, animated: false, scrollPosition: []) | |
} | |
}) | |
} else { | |
collectionView.deselectItem(at: indexPath, animated: animated) | |
} | |
} | |
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// UITableView Objective-C example | |
- (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]; | |
} | |
} | |
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// UITableView Swift example | |
override func viewWillAppear(_ animated: Bool) { | |
super.viewWillAppear(animated) | |
if let selectedIndexPath = tableView.indexPathForSelectedRow { | |
if let coordinator = transitionCoordinator { | |
coordinator.animate(alongsideTransition: { _ in | |
self.tableView.deselectRow(at: selectedIndexPath, animated: true) | |
}, completion: { context in | |
if context.isCancelled { | |
self.tableView.selectRow(at: selectedIndexPath, animated: false, scrollPosition: .none) | |
} | |
}) | |
} else { | |
tableView.deselectRow(at: selectedIndexPath, animated: animated) | |
} | |
} | |
} |
Thanks for putting this up, @smileyborg! I was trying to figure out how UITableViewController
was doing it by disassembling -[UITableViewController viewWillAppear:]
and trying to emulate it, but couldn't quite get it right. Quick question: do we have to deal with checking initiallyInteractive
and isInterruptible
as UIKit does?
Thanks for sharing! I've moved the code to an extension on UITableView
to be able to reuse it easily on any UIViewController
(as @ogres suggested). Here it is in case that anyone needs it:
extension UITableView {
func deselectRow(with transitionCoordinator: UIViewControllerTransitionCoordinator?, animated: Bool) {
guard let selectedIndexPath = self.indexPathForSelectedRow else { return }
guard let coordinator = transitionCoordinator else {
self.deselectRow(at: selectedIndexPath, animated: animated)
return
}
coordinator.animate(alongsideTransition: { _ in
self.deselectRow(at: selectedIndexPath, animated: true)
}, completion: { context in
if context.isCancelled {
self.selectRow(at: selectedIndexPath, animated: false, scrollPosition: .none)
}
})
}
}
And the usage from any UIViewController
:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.tableView.deselectRow(with: self.transitionCoordinator, animated: animated)
}
Cheers!
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Thanks for the nice tip!
How about putting it into an extension like:
and then just call
tableView.deselectRow(along: transitionCoordinator)
fromviewWillAppear
? It will be easier to reuse this functionality