How to convert '__NSIArrayI' to JSON Array in Swift? - ios

Question

I am new to Swift 4 and working on an iOS app. I have the following JSON data retrieved from the server which will be extracted to data table.
[
{
"fund_nav_validity":"24 August to 31 August 2016\n",
"fund_nav_cost":10,
"fund_nav_sell":9.85,
"nav_id":118,
"fund_nav_buy":10,
"fund_id":1,
"nav_as_on_date":"24-Aug-16",
"fund_nav_market":9.95
},
{
"fund_nav_validity":"04 September to 07 September 2016\n",
"fund_nav_cost":10,
"fund_nav_sell":9.85,
"nav_id":117,
"fund_nav_buy":10,
"fund_id":1,
"nav_as_on_date":"01-Sep-16",
"fund_nav_market":9.95
}
]
I have done following task in the navdata function to retrieve the '__NSIArrayI' to JSON:
func getNAVData(){
Alamofire.request(url, method: .post).responseJSON{
response in
if response.result.isSuccess{
print("Success")
//let navDataJSON : JSON = JSON(response.result.value!
let navDataJSON : JSON = JSON(response.result.value!)
print(navDataJSON)
}else{
print("Failed")
}
}
}
I need to convert it to JSON Array which is done in java. How to do the similar task in Swift 4?

Answer 1

you are in the right way, in here you need to convert your JSON response to array the reason your json started with this type[{}] and check your JSON response contains the value or not in intially. try the below code
if response.result.isSuccess{
print("Success")
// convert your JSON to swiftyJSON array type if your JSON response as array as well as check its contains data or not
guard let resJson = JSON(responseObject.result.value!).array , !resJson.isEmpty else { return
}
// create the Swifty JSON array for global access like wise
var navDataJSON = [JSON]() //[JSON]() --> Swifty-JSON array memory allocation.
navDataJSON = resJson
}

Answer 2

You're getting the JSON array and if you want to convert to model Array then you can use create Model Struct and confirm to Decodable Protocol, without using SwiftyJSON using inbuilt solution to parse JSON.
import Foundation
// MARK: - Element
struct Model: Decodable {
let fundNavValidity: String
let fundNavCost: Int
let fundNavSell: Double
let navId: Int
let fundNavBuy: Int
let fundId: Int
let navAsOnDate: String
let fundNavMarket: Double
enum CodingKeys: String, CodingKey {
case fundNavValidity = "fund_nav_validity"
case fundNavCost = "fund_nav_cost"
case fundNavSell = "fund_nav_sell"
case navId = "nav_id"
case fundNavBuy = "fund_nav_buy"
case fundId = "fund_id"
case navAsOnDate = "nav_as_on_date"
case fundNavMarket = "fund_nav_market"
}
}
then in getNAVData method you can use JSONDecoder to covert to Model struct array like below
func getNAVData() {
Alamofire.request(url, method: .post).responseJSON {
response in
switch response.result {
case .success(let data):
do {
let modelArray = try JSONDecoder().decode([Model].self, from: data)
print(modelArray)
} catch {
print("Error: \(error)")
}
case .failure(let error):
print(error.localizedDescription)
}
}
}

Answer 3

If you want to use SwiftyJSON return responseData rather than responseJSON. This avoids a double conversion, and handle always a potential error
func getNAVData(){
Alamofire.request(url, method: .post).responseData { response in
switch response.result {
case .success(let data):
let navDataJSON = JSON(data).arrayValue
print(navDataJSON)
case .failure(let error): print(error)
}
}
}
The result navDataJSON is a JSON array.
However in Swift 4+ it's highly recommended to use the more efficient and built-in Codable protocol
struct Fund : Decodable {
let fundNavValidity, navAsOnDate : String
let fundNavCost, navId, fundNavBuy, fundId : Int
let fundNavSell, fundNavMarket : Double
}
func getNAVData(){
Alamofire.request(url, method: .post).responseData { response in
switch response.result {
case .success(let data):
do {
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let navDataJSON = decoder.decode([Fund].self, from : data)
print(navDataJSON)
} catch { print(error) }
case .failure(let error): print(error)
}
}
}
The result is an array of Fund structs.