RxDataSources cell reload animations not working properly - ios

Question

I am having some issues with the RxDataSources cell reload animations for RxSwift. I have a simple table setup like so:
import UIKit
import RxDataSources
import RxCocoa
import RxSwift
import Fakery
class ViewController1: UIViewController {
#IBOutlet weak var tableView: UITableView!
let bag = DisposeBag()
override func viewDidLoad() {
super.viewDidLoad()
setupTableView()
}
private func setupTableView() {
tableView.register(UINib(nibName: "TestTableViewCell", bundle: nil), forCellReuseIdentifier: "cell")
let dataSource = RxTableViewSectionedAnimatedDataSource<SectionOfTestData>(
animationConfiguration: AnimationConfiguration(insertAnimation: .none, reloadAnimation: .none, deleteAnimation: .none),
configureCell: { dataSource, tableView, indexPath, element in
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TestTableViewCell
cell.testData = element
return cell
})
someData
.bind(to: tableView.rx.items(dataSource: dataSource))
.disposed(by: bag)
}
let someData = BehaviorRelay<[SectionOfTestData]>(value: [SectionOfTestData(items: [
TestData(color: .red, name: "Henry"),
TestData(color: .blue, name: "Josh")
])])
#IBAction func didTapUpdateButton(_ sender: Any) {
let colors: [UIColor] = [.blue, .purple, .orange, .red, .brown]
let items = someData.value.first!.items
// Add random data when button is tapped
someData.accept([SectionOfTestData(items: items + [TestData(color: colors.randomElement()!, name: Faker().name.firstName())])])
}
}
The models:
struct TestData {
let color: UIColor
let name: String
}
extension TestData: IdentifiableType, Equatable {
typealias Identity = Int
var identity: Identity {
return Int.random(in: 0..<20000)
}
}
struct SectionOfTestData {
var items: [Item]
var identity: Int {
return 0
}
}
extension SectionOfTestData: AnimatableSectionModelType {
typealias Identity = Int
typealias Item = TestData
// Implement default init
init(original: SectionOfTestData, items: [Item]) {
self = original
self.items = items
}
}
class TestTableViewCell: UITableViewCell {
#IBOutlet weak var colorView: UIView!
#IBOutlet weak var nameLabel: UILabel!
var testData: TestData! {
didSet {
colorView.backgroundColor = testData.color
nameLabel.text = testData.name
}
}
}
When the button is tapped the BehaviorRelay is updated and the table seems to refresh however the "animations" are always the same. In the supplied code I have actually set all animation types to .none yet it is still performing an animation. If I try to change the animation type to another type such as .bottom again the animation is the same. What am I doing wrong here?
Is this a reload animation or insert animation? I have no idea if the table reloads or inserts when the data is updated, I can't find any information in the documents. Any pointers on this would be greatly appreciated!

Answer 1

Your problem is:
var identity: Identity {
return Int.random(in: 0..<20000)
}
RxDataSources uses the identity value in order to compute the changeset.
You have implemented it in a way that essentially returns a new value each time (unless you get a collision) so from the framework point of view, you are always removing all the items and adding new items. You can check this by implementing
decideViewTransition: { _, _, changeset in
print(changeset)
return .animated
}

Answer 2

To complete the accepted answer :
make a uuid and pass it to identity:
let id = UUID().uuidString
var identity: String {
return id
}
then the animations work perfectly.