Swift 4 - Nesting JSON Response for Class Structure into TableViewCell - ios

Question

I've got the following structures to aid in returning data from a JSON web api:
// To parse the JSON, add this file to your project and do:
//
// let story = try? JSONDecoder().decode(Story.self, from: jsonData)
import Foundation
typealias Story = [StoryElement]
struct StoryElement: Codable {
let id: Int
let url: String
let storyPublic, featured: Bool
let added, modified: String
let itemType: ItemType
let collection: JSONNull?
let owner: Owner
let files: Files
let tags: [ItemType]
let elementTexts: [ElementText]
let extendedResources: ExtendedResources
enum CodingKeys: String, CodingKey {
case id, url
case storyPublic = "public"
case featured, added, modified
case itemType = "item_type"
case collection, owner, files, tags
case elementTexts = "element_texts"
case extendedResources = "extended_resources"
}
}
struct ElementText: Codable {
let html: Bool
let text: String
let elementSet: ElementSet
let element: Element
enum CodingKeys: String, CodingKey {
case html, text
case elementSet = "element_set"
case element
}
}
struct Element: Codable {
let id: Int
let url, name: String
let resource: ElementResource
}
enum ElementResource: String, Codable {
case elements = "elements"
}
struct ElementSet: Codable {
let id: Int
let url: URL
let name: Name
let resource: ElementSetResource
}
enum Name: String, Codable {
case dublinCore = "Dublin Core"
case itemTypeMetadata = "Item Type Metadata"
}
enum ElementSetResource: String, Codable {
case elementSets = "element_sets"
}
enum URL: String, Codable {
case httpWWWRalstoncemeteryCOMGreeleyAPIElementSets1 = "http://www.ralstoncemetery.com/greeley/api/element_sets/1"
case httpWWWRalstoncemeteryCOMGreeleyAPIElementSets3 = "http://www.ralstoncemetery.com/greeley/api/element_sets/3"
}
struct ExtendedResources: Codable {
let exhibitPages: Files
let geolocations: Owner
enum CodingKeys: String, CodingKey {
case exhibitPages = "exhibit_pages"
case geolocations
}
}
struct Files: Codable {
let count: Int
let url, resource: String
}
struct Owner: Codable {
let id: Int
let url, resource: String
}
struct ItemType: Codable {
let id: Int
let url, name, resource: String
}
// MARK: Encode/decode helpers
class JSONNull: Codable {
public init() {}
public required init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
if !container.decodeNil() {
throw DecodingError.typeMismatch(JSONNull.self, DecodingError.Context(codingPath: decoder.codingPath, debugDescription: "Wrong type for JSONNull"))
}
}
public func encode(to encoder: Encoder) throws {
var container = encoder.singleValueContainer()
try container.encodeNil()
}
}
You can see the JSON output I am working with, as well as the original structures here: https://app.quicktype.io?share=oAMNjooSzgpraWpf1KIj (just for reference).
The data (I believe) is returned successfully and parsed correctly, the only issue comes down to myself not being as familiar (I'm in the process of trying to learn a bit more).
So I have a TableViewController and in that I have a cell with the following coded into it:
struct StoryCellViewModel {
let id: Int
let url: String
let storyPublic, featured: Bool
let added, modified: String
}
And in the actual TableViewController under the viewDidLoad() I have this portion of script:
print(story)
self.cellViewModels = story.map{
StoryCellViewModel(id: $0.id, url: $0.url, storyPublic: $0.storyPublic, featured: $0.featured, added: $0.added, modified: $0.modified)
}
and a little bit lower than that, I have:
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "StoryCell", for: indexPath)
let cellViewModel = cellViewModels[indexPath.row]
cell.textLabel?.text = String(cellViewModel.id)
cell.detailTextLabel?.text = cellViewModel.modified
return cell
}
I will make it known that all of this works, the id and modified (both just being used as tests to ensure the connection and printing works properly) are fine, but my question comes up here:
If we go back to the structures there is this portion:
struct ElementText: Codable {
let html: Bool
let text: String
let elementSet: ElementSet
let element: Element
enum CodingKeys: String, CodingKey {
case html, text
case elementSet = "element_set"
case element
}
}
Which refers to the following portion of example JSON:
"element_texts": [
{
"html": false,
"text": "Woehler and Force Farm Equipment Building",
"element_set": {
"id": 1,
"url": "http://www.ralstoncemetery.com/greeley/api/element_sets/1",
"name": "Dublin Core",
"resource": "element_sets"
},
"element": {
"id": 50,
"url": "http://www.ralstoncemetery.com/greeley/api/elements/50",
"name": "Title",
"resource": "elements"
}
},
{
"html": false,
"text": "Woehler and Force Farm Equipment",
"element_set": {
"id": 1,
"url": "http://www.ralstoncemetery.com/greeley/api/element_sets/1",
"name": "Dublin Core",
"resource": "element_sets"
},
"element": {
"id": 39,
"url": "http://www.ralstoncemetery.com/greeley/api/elements/39",
"name": "Creator",
"resource": "elements"
}
},
{
"html": false,
"text": "Street view of the front exterior of Woehler and Force Farm Equipment. Several automobiles are visible through the windows of the store. The alley along the side of the building is also visible. There are several signs along the front of the building reading, 'Farm Equipment,' 'Kaiser Frazer W&F,' and 'Woehler & Force.'; Verso There is a sticker with typed black ink reading, 'Woehler & Force 1316-22 8th Ave. - Greeley, CO 1947. Orig. env. says Liberty Trucker Parts Co./ 690 Lincoln St./F.V. Altwater/POB 1889/Denver, Colo.'",
"element_set": {
"id": 3,
"url": "http://www.ralstoncemetery.com/greeley/api/element_sets/3",
"name": "Item Type Metadata",
"resource": "element_sets"
},
"element": {
"id": 54,
"url": "http://www.ralstoncemetery.com/greeley/api/elements/54",
"name": "Story",
"resource": "elements"
}
}
],
**So my question is: ** How would I go about printing out say the first of the element_texts (The one that has "Woehler and Force Farm Equipment Building" set for the text field)?
If there is any further explanation required, I'll be happy to type it up. Or if anyone has any resources for this level of nesting, I'd be very grateful. Thank you -

Answer 1

story is an array of StoryElement (why not stories?)
The type of property elementTexts in StoryElement is an array of ElementText
So basically you need two loops to iterate over story and elementTexts
for aStory in story {
for elementText in aStory.elementTexts {
print(elementText.text)
}
}

Answer 2

First of all in "CellForRowat" call let cell = dequeueReusableCellWithIdentifier:#"cell" forIndexPath:indexPath etc.
then place text in cell.text

Answer 3

Create a array like this . var AllTexts = [String]()
you can fetch json data so many ways like JsonDecode/JSONSerialization, i am using JSONSerialization. After fetching data i am appending text values in to array.
do {
let data = try Data(contentsOf: URL(fileURLWithPath: path), options: .mappedIfSafe)
let jsonResult = try JSONSerialization.jsonObject(with: data, options: .mutableLeaves) as! [String: Any]
for (key,value) in jsonResult {
print(key)
if let result2:[[String:Any]] = value as? [[String:Any]]{
for dict in result2 {
for (key,value) in dict {
if key == "text" {
self.AllTexts.append(value as! String)
}
}
}
}
}
print(self.AllTexts)
} catch {
// handle error
print(error)
}