I have this simple Struct:
protocol DocumentSerializable {
init?(dictionary:[String:Any])
}
struct Item {
var title:String
var text:String?
var dictionary:[String:Any] {
return [
"title":title,
"text":text,
]
}
}
extension Item : DocumentSerializable {
init?(dictionary: [String : Any]) {
guard let title = dictionary["title"] as? String,
let text = dictionary["text"] as? String? else {return nil}
self.init(title: title, text: text)
}
}
When I recive my json, I put it in an array...
if let array = result?.data as? Array<[String:Any]> {...
How can I convert this array into an array of Items? var itemsArray = [Item]()
The two arrays have exactly the same structure
Thanks
Use
struct Item :Decodable {
let title:String
let text:String?
}
//
do {
let root = try JSONDecoder().decode([Item].self, from:jsonData)
print(root)
}
catch {
print(error)
}
Use compactMap, it handles also the nil cases:
itemsArray = array.compactMap{ Item(dictionary: $0) }
However in Swift 4 it's highly recommended to use the Codable protocol
Related
I am trying to create a generic array with different models. I have a parser method like that. But it doesn't work because it returns [Any] and it's not typesafe. I need to access my Movie and CastMember objects after parse method. I will use this array in my tableviewcontroller delegate methods. How can I do that?
static func parseSearchResult(_ data:Dictionary<String, AnyObject>) -> [Any] {
var array = [Any]()
let jsonData = JSON(data)
if let resultData = jsonData["results"].arrayObject {
let result = resultData as! [[String:AnyObject]]
for element in result {
if((element["media_type"]?.isEqual("person"))!){
let person = CastMember(json: element)
array.append(person)
}
else if((element["media_type"]?.isEqual("movie"))!){
let movie = Movie(json: element)
array.append(movie)
}
}
}
return array
}
and these are my structs
struct CastMember{
var id : Int?
var originalName : String?
var castName : String?
var picturePath : String?
init(json: [String:Any]){
originalName = json["name"] as? String
id = json["id"] as? Int
castName = json["character"] as? String
picturePath = "https://image.tmdb.org/t/p/w200/"
picturePath?.append((json["profile_path"] as? String) ?? "")
}
}
struct Movie{
var id : Int?
var title : String?
var imagePath : String?
init(json: [String:Any]){
title = json["title"] as? String
id = json["id"] as? Int
imagePath = "https://image.tmdb.org/t/p/w200/"
imagePath?.append((json["poster_path"] as? String)!)
}
}
Make your Movie and CastMember classes confirm to the protocol Codable.
also you will have to write a struct or class which matches the response data , like it must have an array of results and any other key coming in response.
struct ResponseModel<T> : Codable {
let results : [T]
}
then decode it like this :
let response : ResponseModel = JSONDecoder.decode(T.self)
You should make a protocol
Example:
enum MediaType {
case movie, castMember
}
protocol SearchResult {
var title: String { get }
var mediaType: MediaType { get }
}
struct SearchResultViewModel: SearchResult {
let title: String
let mediaType: MediaType
init(title: String, mediaType: MediaType) {
self.title = title
self.mediaType = mediaType
}
}
Then your parseSearchResult should return an array of [SearchResult] objects that conforms to the protocol, in this case, an array of SearchResultViewModel
I have a dictionary of values
class Objects {
let values = [
"AAA": ["AAAAAAA", "111111111"],
"BBB": ["BBBBBBBB", "2222222"],
"CCC": ["CCCCCCCC", "3333333333"],
"DDD": ["DDDDDD", "44444444"],
]
}
Which I turn into custom objects and display in a tableview.
struct Object {
var heading : String!
var imageName: String!
}
Then the user can select two objects to store in UserDefaults
let defaults = UserDefaults.standard
func addObject(_ object1: String, object2: String) {
// Get objects for user
var userObjects = fetchObjectsFromUserDefaults()
// Add to user currencies
userObjects.append([object1,object2])
//Update user defaults value for key
// [ [Object1, Object2], [Object1, Object2] ]
defaults.set(userObject, forKey: "userCurrencies")
}
// Gets [[String]] values from user defaults for key
func fetchObjectsFromUserDefaults() -> [[String]] {
if let objects = UserDefaults.standard.value(forKey: "userObjects") {
return objects as! [[String]]
} else {
return []
}
}
// Uses [[String]] values and turns them into objects by using the dictionary to determine property values
func getObject() -> [[Object]] {
let userObject = fetchObjectsFromUserDefaults()
// [ [Object1, Object2], [Object1, Object2] ]
let object = Object()
var fetchedObject = [[Object]]()
if !userObjects.isEmpty {
for c in userObjects {
var set = [Object]()
if let val = object.available[c[0]] {
set.append(Currency(currencyTitle: c[0], imageName: val[0] ))
}
if let val2 = object.available[c[1]] {
set.append(Currency(currencyTitle: c[0], imageName: val2[0] ))
}
if !set.isEmpty {
fetchedObjects.append(set)
}
}
return fetchedObjects
}
return [[]]
}
View Controller
Here I get the objects to load into the TableView
let fetched = dataManager.getObjects
print(fetched)
self.objects = fetched()
However this prints out
(Function)
What am I doing wrong and is their a better method of storing and retrieving this data from user defaults ? I feel this is over kill and there is a swifter and safer approach.
Step 1.
Make your struct Codable. The compiler will write all of the functions for you if all of the members of your struct are Codable and fortunately String is Codable so its just:
struct Object: Codable {
var heading : String!
var imageName: String!
}
Step 2.
The problem with Codable is that it converts to and from Data, but you want to convert to and from a Dictionary. Fortunately JSONSerialization converts from Data to Dictionary so make a new protocol and give it a default implementation with a protocol extension:
protocol JSONRepresentable {
init?(json: [String: Any])
func json() -> [String: Any]
}
extension JSONRepresentable where Self: Codable {
init?(json: [String:Any]) {
guard let value = (try? JSONSerialization.data(withJSONObject: json, options: []))
.flatMap ({ try? JSONDecoder().decode(Self.self, from: $0) }) else {
return nil
}
self = value
}
func json() -> [String:Any] {
return (try? JSONEncoder().encode(self))
.flatMap { try? JSONSerialization.jsonObject(with: $0, options: []) } as? [String: Any] ?? [:]
}
}
Step 3.
Conform your struct to JSONRepresentable
struct Object: Codable, JSONRepresentable {
var heading : String!
var imageName: String!
}
Step 4.
Place your object into Userdefaults and get it out again:
let o = Object.init(heading: "s", imageName: "a").json()
UserDefaults.standard.set(o, forKey: "test")
print(Object.init(json: UserDefaults.standard.dictionary(forKey: "test") ?? [:]))
Here is the whole playground if you want to try:
import UIKit
struct Object: Codable, JSONRepresentable {
var heading : String!
var imageName: String!
}
protocol JSONRepresentable {
init?(json: [String: Any])
func json() -> [String: Any]
}
extension JSONRepresentable where Self: Codable {
init?(json: [String:Any]) {
guard let value = (try? JSONSerialization.data(withJSONObject: json, options: []))
.flatMap ({ try? JSONDecoder().decode(Self.self, from: $0) }) else {
return nil
}
self = value
}
func json() -> [String:Any] {
return (try? JSONEncoder().encode(self))
.flatMap { try? JSONSerialization.jsonObject(with: $0, options: []) } as? [String: Any] ?? [:]
}
}
let o = Object.init(heading: "s", imageName: "a").json()
UserDefaults.standard.set(o, forKey: "test")
print(Object.init(json: UserDefaults.standard.dictionary(forKey: "test") ?? [:]))
I would like to know if there is a more elegant way to write this:
struct S {
var state: [String: Any]
public var amounts: [Amount] {
var result: [Amount] = []
(self.state["amounts"] as? [Any]?)??.forEach({ a in
result.append(Amount(a))
})
return result
}
}
struct Amount {
init(_ any: Any?) {}
}
I have tried using map for array, but I can't find a way to do so.
You could also use guard let and early return, which would make it look bit better.
Here is how I did it,
struct S {
var state: [String: Any]
public var amounts: [Amount] {
guard let amounts = state["amounts"] as? [Any] else {
return []
}
return amounts.map(Amount.init)
}
}
struct S {
var state: [String: Any]
public var amounts: [Amount] {
return (self.state["amounts"] as? [Any] ?? []).map({ Amount($0) })
}
}
struct Amount {
init(_ any: Any?) {}
}
You are using too many unnecessary optionals here. You should always use as? with a non-optional type. And instead of forEach, use map:
public var amounts: [Amount] {
if let anyArray = self.state["amounts"] as? [Any] {
return anyArray.map(Amount.init)
} else {
return []
}
}
You can get that working in a single line,
public var amounts: [Amount] {
return (self.state["amounts"] as? [Any])?.map({ Amount($0) }) ?? []
}
init(_ state: [Amount]) {
self.init()
guard let amounts = state["amounts"] as? [Any] else {
return []
}
return amounts.map(Amount.init)
}
I want to create one func which i can used with various struct.
I have several struct and I want use one func with all my struct.
I work with Firestore and want use this one func to access the Firestore.
My first struct:
struct Profile {
var name = ""
var surname = ""
var email = ""
var dictionary: [String: Any] {
return [
"name": name,
"surname": surname,
"email": email
]
}
}
extension Profile: DocumentSerializable {
init?(dictionary: [String: Any], id: String) {
let name = dictionary["name"] as? String ?? ""
let surname = dictionary["surname"] as? String ?? ""
let email = dictionary["email"] as? String ?? ""
self.init(name: name,
surname: surname,
email: email)
}
}
My second struct:
struct FavoriteList {
var favoriteList: [String]
var id: String
var dictionary: [String: Any] {
return [
"favoriteList": favoriteList,
"id": id
]
}
}
extension FavoriteList: DocumentSerializable {
init?(dictionary: [String : Any], id: String) {
let favoriteList = dictionary["favorite"] as? [String] ?? [""]
let id = id
self.init(favoriteList: favoriteList, id: id)
}
}
And my func which I used now to load data from firestore:
func observeQuery() {
guard let query = query else { return }
let time = DispatchTime.now() + 0.5
listener = query.addSnapshotListener { [unowned self] (snapshot, error) in
if let snapshot = snapshot {
DispatchQueue.main.asyncAfter(deadline: time) {
let profileModels = snapshot.documents.map { (document) -> Profile in
if let profileModel = Profile(dictionary: document.data(), id: document.documentID) {
return profileModel
} else {
fatalError("Error!")
}
}
self.profile = profileModels
self.document = snapshot.documents
self.tableView.reloadData()
}
}
}
}
So how I can make func observeQuery to use my structs Profile or FavouriteList?
You can use Generic Functions :
func observeQuery<T>(someObject: T) {
if someObject is Profile {
//do something
} else if someObject is FavouriteList {
//do something
}
}
im trying to dispaly array object come from api response as [[String: Any]] at table view
and thats my struct
class CategoriesDep: NSObject {
var depName: String
var depImage: String
var subName = [subData]()
init?(dict: [String: JSON]) {
guard let image = dict["main_department_image"]?.imagePath, !image.isEmpty else { return nil }
self.depImage = image
self.depName = (dict["main_department_name"]?.string)!
}
struct subData {
var dep: String
init(dic: [String: Any]) {
self.dep = dic["sub_department_name"] as! String
}
}
}
Please check below code to parse your json
class CategoriesDep: NSObject {
var depName: String
var depImage: String
var subName = [subData]()
init?(dict: [String: Any]) {
guard let image = dict["main_department_image"] as? String, !image.isEmpty else { return nil }
self.depImage = image
self.depName = (dict["main_department_name"] as? String)!
subName = []
for subDict in (dict["sub_depart"] as? [[String:Any]] ?? []){
subName.append(subData(dic: subDict))
}
}
}
struct subData {
var dep: String
var image :String
var id : String
init(dic: [String: Any]) {
self.dep = dic["sub_department_name"] as! String
self.image = dic["sub_department_image"] as! String
self.id = dic["sub_department_id"] as! String
}
}
and if you want to access subdata struct out side of CategoriesDep class then declare structure outside CategoriesDep class
Parse your given json Respoise like
let json = [
[ "sub_depart" : [
[ "sub_department_name" : "hos", "sub_department_id" : "6", "sub_department_image" : "23.jpg"
]
],
"main_department_id" : "2",
"main_department_name" : "main ",
"main_department_image" : "14.jpg"
],
]
var catDepart : [CategoriesDep] = []
for dict in json {
catDepart.append(CategoriesDep(dict: dict)!)
}
print(catDepart[0].subName[0].dep)
You could use Codabel protocol to be more swifty ;) and cleaning up the code.
let jsonString = "[{\"sub_depart\" : [ {\"sub_department_name\" : \"hos\", \"sub_department_id\" : \"6\", \"sub_department_image\" : \"23.jpg\" } ], \"main_department_id\" : \"2\", \"main_department_name\" : \"main \", \"main_department_image\" : \"14.jpg\"}]"
struct CategoriesDep: Codable {
let mainDepartmentName: String
let mainDepartmentImage: String
let mainDepartmentId: String
var subDepart: [SubData] = []
}
struct SubData: Codable {
let subDepartmentName: String
let subDepartmentImage: String
let subDepartmentId: String
}
if let jsonData = jsonString.data(using: .utf8) {
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
var departments: [CategoriesDep]? = try? decoder.decode([CategoriesDep].self, from: jsonData)
...
}
Note the decoder.keyDecodingStrategy = .convertFromSnakeCase here which is mapping the underscore (snake_case) API property names to your camelCase ones.
If you need different property names you have to implement CodingKeys enum to map them.
For more detailed information check this link.