Realm on Swift - Creating Relationship - ios

Question

I have two classes that form a one to many relationship:
class FooA: Object {
dynamic var someAValue: String
let fooBList = List<FooB>()
}
class FooB: Object {
dynamic var someBValue: String
}
I add the object into Realm in this fashion:
let fooA = FooA()
fooA.someAValue = 'a value'
let fooB = FooB()
fooB.someBValue = 'a value'
fooA.fooBList.append(fooB)
let realm = try! Realm()
try! realm.write {
realm.add(fooA)
}
Everything goes well, the object is inserted into Realm. However, when I attempt to access the FooB object like this:
fooA.fooBList[0]
It goes BOOM and the app crashes! So, obviously, I did not insert the relationship object into Realm correctly and the relationship is corrupted. What did I miss in the Realm documentation? Must I create the Array first and add it to the parent object in another fashion?
To update on my question, this is the operation that wants to blow up:
FooApiClient.getFooAObjects()
.subscribeOn(ConcurrentDispatchQueueScheduler(qos: .default))
.observeOn(MainScheduler.instance)
.subscribe { [weak self] in
switch $0 {
case .next(let fooAObjects):
self?.fooAObjects = fooAObjects
case .completed:
self?.fooTableView.reloadData()
loadingView?.hide()
case .error(let error):
loadingView?.hide()
self?.handleError(error)
self?.showNoFooView()
}
}
.addDisposableTo(disposeBag)
The invocation: self?.fooTableView.reloadData() causes to the table view to attempt to display the foo objects retrieved and where it goes BOOM.

Answer 1

Try something like this. It may have some mistakes.
class SomeTableViewController: UITableViewController {
var fooA : FooA?
override func viewDidLoad() {
super.viewDidLoad()
let realm = try! Realm()
if let aFooA = realm.objects(FooA.self).first{
fooA = aFooA
self.reloadTableView()
}
}
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if let _ = fooA{
return fooA!.fooBList.count
}
return 0
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "SomeCell", for: indexPath)
// Configure the cell...
let fooB = fooA!.fooBList[indexPath.row]
cell.titleLabel.text = fooB.someBValue
return cell
}
}