Swift generic enums for as TableView data source - ios

Question

I want to create a UITableViewController that accepts an enum as it's data source.
The thing is, I have quite a few enums that I want it to be able to handle.
I created a protocol called TableViewSelectable and created some enums that conform to it like so:
protocol TableViewSelectable {
}
enum Genders: Int, TableViewSelectable {
case male = 0, female
static let allKeys = [male, female]
static let allNames = [male.getName, female.getName]
var getName: String {
switch self {
case .male:
return "Male"
case .female:
return "Female"
}
}
}
enum Goals: Int, TableViewSelectable {
case gainMuscleMass, getTrimFit, loseWeight
static let allKeys = [gainMuscleMass, getTrimFit, loseWeight]
static let allNames = [gainMuscleMass.getName, getTrimFit.getName, loseWeight.getName]
var getName: String {
switch self {
case .gainMuscleMass:
return "Gain muscle mass"
case .getTrimFit:
return "Get trim & fit"
case .loseWeight:
return "Lose weight"
}
}
}
And I have created an instance variable on my UITableViewController like so:
class ChoiceListTableViewController: UITableViewController {
var data: TableViewSelectable?
}
The problem is I have no idea how to go from here.
What I want to have is the option to give that UITableViewController any enum that conforms to TableViewSelectable in order to use as its data source.
I want to access it on the UITableViewController like this:
final class ChoiceListTableViewController: UITableViewController {
var data: TableViewSelectable?
// MARK: Lifecycle
override func viewDidLoad() {
super.viewDidLoad()
self.clearsSelectionOnViewWillAppear = false
}
}
// MARK: Table View Data Source & Delegate
extension ChoiceListTableViewController {
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return data.allKeys.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "ChoiceTableViewCell", for: indexPath)
cell.textLabel?.text = data.allNames[indexPath.row]
return cell
}
}
Help please? :)

Answer 1

The issue with your current implementation is that the allKeys and allNames static properties that you should be using in your UITableViewDataSource method are not part of the TableViewSelectable protocol, so you cannot access them using the data variable.
You should modify your protocol to include these.
protocol TableViewSelectable {
static var allKeys: [TableViewSelectable] {get}
static var allNames: [String] {get}
}
You also need to modify your enums conforming to it accordingly.
enum Genders: Int, TableViewSelectable {
case male = 0, female
static let allKeys:[TableViewSelectable] = [male, female]
static let allNames = [male.getName, female.getName]
var getName: String {
switch self {
case .male:
return "Male"
case .female:
return "Female"
}
}
}
enum Goals: Int, TableViewSelectable {
case gainMuscleMass, getTrimFit, loseWeight
static let allKeys:[TableViewSelectable] = [gainMuscleMass, getTrimFit, loseWeight]
static let allNames = [gainMuscleMass.getName, getTrimFit.getName, loseWeight.getName]
var getName: String {
switch self {
case .gainMuscleMass:
return "Gain muscle mass"
case .getTrimFit:
return "Get trim & fit"
case .loseWeight:
return "Lose weight"
}
}
}
Then you can simply use data.allKeys and data.allNames to access the corresponding element of these arrays in your data source methods.
class ChoiceListTableViewController: UITableViewController {
var data:TableViewSelectable.Type! // make sure that this is actually initialized before accessing it
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return data.allKeys.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "id", for: indexPath)
cell.textLabel?.text = data.allNames[indexPath.row]
return cell
}
}