Generic UITableViewCell with Different Kind Of JSON data - ios

Question

I like to use a single tableViewCell instance (instead creating separate cells) for different kind of data; used a simple generic approach by creating a protocol for this but how can I populate data from JSON (by avoiding switch-case) in clear way?
protocol CellData {
var title: String { get set }
var subTitle: String { get set }
var image: String { get set }
}
for the singleCell
#IBOutlet weak var titleLabel: UILabel!
#IBOutlet weak var subTitleLabel: UILabel!
#IBOutlet weak var imageView: UIImageView!
{
"data": [
{
"type": "company",
"data": {
"name": "Google",
"sector": "IT",
"logo": "https://www.google.com/logos/doodles/2015/googles-new-logo-5078286822539264.3-hp2x.gif"
}
},
{
"type": "person",
"data": {
"name": "Bill Gates",
"occupation": "Microsoft CEO",
"picture": "https://img.etimg.com/thumb/msid-66398917,width-640,resizemode-4,imgsize-702055/words-of-wisdom.jpg"
}
},
{
"type": "song",
"data": {
"name": "Beat It",
"singer": "M.Jackson",
"thumbnail": "https://cdn.smehost.net/michaeljacksoncom-uslegacyprod/wp-content/uploads/2019/08/Sept2019Mobile.jpg"
}
},
{
"type": "vehicle",
"data": {
"name": "Silver Silver",
"brand": "Silver",
"photo": "https://images.pexels.com/photos/112460/pexels-photo-112460.jpeg?auto=compress&cs=tinysrgb&dpr=1&w=500"
}
}
],
"error": null
}

Answer 1

If you have guarantees about the keys that you can expect, then you could try to parse the data for the first key that is found:
struct CellDataEnvelope: Decodable {
let data: CellData
let type: CellDataType
enum CellDataType: String, Decodable {
case company
case person
case song
case vehicle
}
}
struct CellData: Decodable {
let title: String
let subTitle: String
let image: String
enum CodingKeys: CodingKey {
// title
case name
// subTitle
case sector
case occupation
case singer
case brand
// image
case thumbnail
case picture
case logo
case photo
}
}
extension CellData {
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
self.title = try container.decode(String.self, forKey: .name)
self.subTitle = try tryDecodeString(in: container, keys: [.sector, .occupation, .singer, .brand])
self.image = try tryDecodeString(in: container, keys: [.thumbnail, .picture, .logo, .photo])
}
}
// Attempts to decode a String value from an array of keys, returns the first one to successfully decode.
private func tryDecodeString(
in container: KeyedDecodingContainer<CellData.CodingKeys>,
keys: [CellData.CodingKeys]
) throws -> String {
for key in keys {
if let value = try? container.decode(String.self, forKey: key) {
return value
}
}
throw DecodingError.dataCorrupted(
.init(
codingPath: [],
debugDescription: "Invalid data"
)
)
}
let models = try JSONDecoder().decode([CellDataEnvelope].self, from: Data(json.utf8))
This could become unwieldy if the list of keys will grow substantially or if you don't have guarantees about them.

Answer 2

You can have a model with optional attributes, which means they won't always need to have all of the properties setted, but as mentioned by Vadian, at some point you will need to map what you are receiving.
You can also define all of your keys that are not image or title, as the subtitle (for example, sector or occupation or singer or brand).