Why is this Swift struct instantiation crashing? - ios

Question

I have a Swift struct Reflection like this:
struct Reflection {
let title: String
let body: String
let author: String
let favorite: Bool
let creationDate: Date
let id: UUID
}
extension Reflection {
var plistRepresentation: [String: AnyObject] {
return [
"title": title as AnyObject,
"body": body as AnyObject,
"author": author as AnyObject,
"favorite": favorite as AnyObject,
"creationDate": creationDate as AnyObject,
"id": id as AnyObject
]
}
init(plist: [String: AnyObject]) {
title = plist["title"] as! String
body = plist["body"] as! String
author = plist["author"] as! String
favorite = plist["favorite"] as! Bool
creationDate = plist["creationDate"] as! Date
id = plist["id"] as! UUID
}
}
class StorageController {
fileprivate let documentsDirectoryURL = FileManager.default
.urls(for: .documentDirectory, in: .userDomainMask)
.first!
fileprivate var notesFileURL: URL {
return documentsDirectoryURL
.appendingPathComponent("Notes")
.appendingPathExtension("plist")
}
func save(_ notes: [Reflection]) {
let notesPlist = notes.map { $0.plistRepresentation } as NSArray
notesPlist.write(to: notesFileURL, atomically: true)
}
func fetchNotes() -> [Reflection] {
guard let notePlists = NSArray(contentsOf: notesFileURL) as? [[String: AnyObject]] else {
return []
}
return notePlists.map(Reflection.init(plist:))
}
}
class StateController {
fileprivate let storageController: StorageController
fileprivate(set) var notes: [Reflection]
init(storageController: StorageController) {
self.storageController = storageController
self.notes = storageController.fetchNotes()
}
func add(_ note: Reflection) {
notes.append(note)
storageController.save(notes)
}
func update(_ note: Reflection) {
for (index, storedNote) in notes.enumerated() {
guard storedNote.id == note.id else {
continue
}
notes[index] = note
storageController.save(notes)
break
}
}
}
Instantiating a Reflection like this in viewWillAppear crashes my app:
import UIKit
class NotesViewController: UIViewController {
var stateController: StateController!
fileprivate var dataSource: FeedDataSource!
#IBOutlet var tableView: UITableView!
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
let reflection = Reflection(title: "Hello", body: "world", author: "Alex", favorite: true, creationDate: Date(), id: UUID())
//stateController.add(reflection)
dataSource = FeedDataSource(notes: stateController.notes)
tableView.dataSource = dataSource
tableView.reloadData()
}
class FeedDataSource: NSObject {
var notes: [Reflection]!
init(notes: [Reflection]) {
self.notes = notes
}
}
extension FeedDataSource: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return notes.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "reflectionCell", for: indexPath) as! ReflectionCell
let index = indexPath.row
let note = notes[index]
cell.model = ReflectionCell.Model(data: note)
return cell
}
}
The cell class:
class ReflectionCell: UITableViewCell {
#IBOutlet weak fileprivate var titleLabel: UILabel!
#IBOutlet weak fileprivate var bodyLabel: UILabel!
#IBOutlet weak fileprivate var authorLabel: UILabel!
#IBOutlet weak fileprivate var bookmarkButton: UIButton!
fileprivate var id: UUID!
var model: Model? {
didSet {
guard let model = model else {
return
}
titleLabel.text = model.title
bodyLabel.text = model.body
authorLabel.text = model.author
bookmarkButton.isSelected = model.favorite
id = model.id
}
}
override func awakeFromNib() {
super.awakeFromNib()
bookmarkButton.setImage(#imageLiteral(resourceName: "Bookmark-Highlighted"), for: .selected)
}
}
extension ReflectionCell {
struct Model {
let title: String
let body: String
let author: String
let favorite: Bool
let id: UUID
init(data: Reflection) {
title = data.title
body = data.body
author = data.author
favorite = data.favorite
id = data.id
}
}
}
I get no console output, just a main thread SIGABRT error. What could be going on?

Answer 1

Like an idiot I was cleaning up my code and commented out the line registering the nib for the reuse identifier. However, I do think it would help if Xcode could print out a useful error message for such a mistake.