In the WWDC video on "Formatters: Make data human-friendly" there is a sample app shown and referenced as being available for download but no app is attached.
antjnr
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Last seen
User for
From
Melbourne, VIC, Australia
Post
Replies
Boosts
Views
Activity
I have a self-sizing collectionView inside of a UITableViewCell.
The structure is as follows. A:
ViewController: UIViewController()
which contains a tableView property declared as:
tableView: UITableView().
This contains a number of customTableViewCell/s that are a custom subclass declared as:
CustomTableViewCell: UITableViewCell().
Each tableViewCell contains a customCollectionView declared as:
CustomCollectionView: UICollectionView().
This collectionView contains a number of customCollectionViewCell/s declared as:
CustomCollectionViewCell: UICollectionViewCell()
Inside the ViewController class, the tableView is configured with the following:
tableView.rowHeight = UITableView.automaticDimension
tableView.estimatedRowHeight = 40
Inside the customTableViewCell class, where the customCollectionView is declared, the customCollectionView is constrained inside the customTableViewCell to the customTableViewCell.contentView using the top, bottom, leading and trailing anchors.
QUESTION 1:
The only way I can get the tableView to load correctly on initial load is to call:
override func viewDidAppear(_ animated: Bool) {
tableView.beginUpdates()
tableView.endUpdates()
}
First question - Is this the correct way of getting the parent tableView to update itself? It works but because it is being called on viewDidAppear, the resizing activity can be seen by the user. If I try and call it in viewWillAppear, then this is too early and the content of the customTableViewCell hasn't finished loading and being laid out.
QUESTION 2:
When the user interacts with the content inside a customCollectionViewCell, the collectionView content changes - customCollectionViewCells are either added or removed from the customCollectionView - this causes the overall customCollectionView to either grow or shrink vertically in height.
When this happens, even though autolayout has pinned the customCollectionView to the edges of the customTableViewCell.contentView , the customTableViewCell is not automatically resizing itself even though it is a self-sizing cell.
I've looked around and there are a lot of tableView.reloadData() recommendations - something Apple suggests not using.
Alternatively, I've been able to get it to work two ways:
Option 1:
In the customCollectionView class, calling self.superview?.superview?.superview to get to the UITableView to then update the tableView. This is the method I'm using when the content inside the customCollectionView is updated:
func removeItem(titleOfItem: String) {
guard let indexOfItemToRemove = sampleData.firstIndex(where: {$0.title == titleOfItem}) else { return }
sampleData.remove(at: indexOfItemToRemove)
DispatchQueue.main.async {
self.performBatchUpdates({
self.deleteItems(at: [IndexPath(item: indexOfItemToRemove, section: 0)])
}) { (true) in
if let tableView = self.superview?.superview?.superview as? UITableView {
tableView.beginUpdates()
tableView.endUpdates()
DispatchQueue.main.async {
tableView.layoutIfNeeded()
}
}
}
}
}
Option 2:
By using a delegate method. So in the customCollectionView class:
func removeItem(titleOfItem: String) {
guard let indexOfItemToRemove = sampleData.firstIndex(where: {$0.title == titleOfItem}) else { return }
sampleData.remove(at: indexOfItemToRemove)
DispatchQueue.main.async {
self.performBatchUpdates({
self.deleteItems(at: [IndexPath(item: indexOfItemToRemove, section: 0)])
}) { (true) in
self.updateDelegate?.needToUpdate()
}
}
}
Then, in the ViewController class, via the delegate, I do the following:
func customCollectionViewUpdatesHaveOccurred() {
tableView.beginUpdates()
tableView.endUpdates()
}
So the second question is - am I missing something because autolayout is not automatically resizing the customTableViewCell based on its content? Or are my above workarounds the correct way of doing this and if so, which is the better option? If not, then how should I be doing this?
Apologies if this is too long, I've never posted on here and just trying to be super clear. Happy to share the actual code/project file if that helps.