I'm new to swift i am sorry if this is a stupid question
I am trying to expand my knowledge in macOS development and i am trying out new things
i am parsing a json file from an url
it works fine in the do{}catch{} brackets however, i want to use what i get from the json data in other parts of the program.
i created some variables to store the values.
However, they go back to their initial value once the do{}catch{} execution is done
how can i store the values I got
#IBAction func buttonPressed(_ sender: Any) {
var summonerNameGlobal: String = ""
var summonerIdGlobal: String = ""
var summonerPuuidGlobal: String = ""
var summonerAccountIdGlobal: String = ""
let jsonString = "https://na1.api.riotgames.com/lol/summoner/v4/summoners/by-name/john?api_key=\(apiKey)"
guard let url = URL(string: jsonString) else {return}
URLSession.shared.dataTask(with: url) { (data, response, err) in
guard let data = data else {return}
DispatchQueue.main.async {
do {
let summoner = try JSONDecoder().decode(SummonerInfo.self, from: data)
self.summonerIdLabel.stringValue = summoner.id
summonerNameGlobal = summoner.name
summonerIdGlobal = summoner.id
summonerAccountIdGlobal = summoner.accountId
summonerPuuidGlobal = summoner.puuid
} catch {
print(error)
}
}
}.resume()
print(summonerNameGlobal)
print(summonerPuuidGlobal)
print(summonerIdGlobal)
print(summonerAccountIdGlobal)
}
They are not going to default again but you are checking them before they are being set ... because async function take some time to get response from server but your print statements run immediately
What you can do is to check values once they are set
func callApi(completion: #escaping (SummonerInfo?)->Void){
let jsonString = "https://na1.api.riotgames.com/lol/summoner/v4/summoners/by-name/john?api_key=\(apiKey)"
guard let url = URL(string: jsonString) else {return}
URLSession.shared.dataTask(with: url) { (data, response, err) in
guard let data = data else {return}
DispatchQueue.main.async {
do {
let summoner = try JSONDecoder().decode(SummonerInfo.self, from: data)
completion(summoner)
} catch {
completion(nil)
print(error)
}
}
}.resume()
}
#IBAction func buttonPressed(_ sender: Any) {
callApi { [weak self] info in
if let getInfo = info {
print(getInfo.name)
print(getInfo.id)
print(getInfo.accountId)
print(getInfo.puuid)
} else {
print("data is nil")
}
}
}
Related
Ive got an answer from an XML API that comes back to me as a String. I need it to be an int so that i can add it to another value in laters on. Ive tried to unwrap it and read it as an int but it didnt work. Ive also tried trimming blank spaces and then unwrap it but that didnt work either.
If i set the leading let value: Int it will give me an error saying that the value is not in the correct format.
What i have so far is this:
struct HydroData: Decodable {
let value: String
let textTranslationId: String?
let titleTranslationId: String?
let style: String?
}
struct HydroResult: Decodable {
let HydroData: [HydroData]
}
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
calcIndex()
let url = URL(string: "https://driftsdata.statnett.no/restapi/ProductionConsumption/GetLatestDetailedOverview")!
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard let data = data else {
print("No data")
return
}
do {
let result = try JSONDecoder().decode(HydroResult.self, from: data)
if let seDesc = result.HydroData.filter({ $0.titleTranslationId == "ProductionConsumption.HydroSEDesc" }).first {
let hydroValue = seDesc.value
print(seDesc.value)
} else {
print("Error: no value")
}
} catch {
print(error.localizedDescription)
}
}
task.resume() }
func calcIndex(){
let newHydro = hydroValue + 1000
print(newHydro)
}
}
You need to use initializer for Int that accepts String as parameter Int(). Also, I've fixed the issue you're gonna face when you try to use the Int(seDesc.value) because it contains a non-decimal-digit character. Here's the entire code:
class ViewController: UIViewController {
var hydroValue = 0
override func viewDidLoad() {
super.viewDidLoad()
calcIndex()
let url = URL(string: "https://driftsdata.statnett.no/restapi/ProductionConsumption/GetLatestDetailedOverview")!
let task = URLSession.shared.dataTask(with: url) { data, response, error in
guard let data = data else {
print("No data")
return
}
do {
let result = try JSONDecoder().decode(HydroResult.self, from: data)
if let seDesc = result.HydroData.filter({ $0.titleTranslationId == "ProductionConsumption.HydroSEDesc" }).first {
let value = seDesc.value.components(separatedBy: CharacterSet.decimalDigits.inverted).joined()
self.hydroValue = Int(value) ?? 0
print(value)
self.calcIndex()
} else {
print("Error: no value")
}
} catch {
print(error.localizedDescription)
}
}
task.resume()
}
func calcIndex(){
let newHydro = hydroValue + 1000
print(newHydro)
}
}
I have a function that connects to an API to retrieve data. The API takes two parameters accessCode (provided by user in a text box) and then UDID (UDID of their device). I can parse the data from within the function, but only locally. I need to store the values that are returned but am unsure on how to return them properly. Essentially I need this to return the json object as a dictionary (I think...) so it can be parsed outside of the async task. I've read through the swift documentation and that's where I found out how to do the requests, but I can't find a way to store the returned values in memory for access outside of the function.
func getResponse(accessCode:String, UDID:String, _ completion: #escaping (NSDictionary) -> ()) {
let urlPath = "https://apihosthere.com/api/validate?accessCode=" + accessCode + "&UDID=" + UDID
guard let url = URL(string: urlPath) else { return }
let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let data = data else { return }
do {
if let jsonResult = try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.mutableContainers) as? NSDictionary {
let results = jsonResult as? NSDictionary
print(results)
completion(results!)
}
} catch {
//Catch Error here...
}
}
task.resume()
}
First of all don't use NSDictionary in Swift, use native [String:Any] and declare the type as optional to return nil if an error occurs.
And never use .mutableContainers in Swift, the option is useless.
func getResponse(accessCode:String, UDID:String, completion: #escaping ([String:Any]?) -> Void)) {
let urlPath = "https://apihosthere.com/api/validate?accessCode=" + accessCode + "&UDID=" + UDID
guard let url = URL(string: urlPath) else { return }
let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
if let error = error else {
print(error)
completion(nil)
return
}
do {
if let jsonResult = try JSONSerialization.jsonObject(with: data!) as? [String:Any] {
print(jsonResult)
completion(jsonResult)
} else {
completion(nil)
}
} catch {
print(error)
completion(nil)
}
}
task.resume()
}
Your mistake is that you don't consider the closure, you have to execute the entire code inside the completion handler
#IBAction func StartWizard(_ sender: UIButton) {
//Store entered access code
let accessCode = AccessCodeField.text!
//Call API to validate Access Code
getResponse(accessCode:accessCode, UDID:myDeviceUDID) { [weak self] result in
if let accessCodeFound = result?["Found"] as? Bool {
print("Value of Found during function:")
//If access code is valid, go to License view
print(accessCodeFound)
if accessCodeFound {
//Load License View
DispatchQueue.main.async {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let licenseController = storyboard.instantiateViewController(identifier: "LicenseViewPanel")
self?.show(licenseController, sender: self)
}
}
}
}
}
Your completion closure should handle the obtained data. You would call the function like this:
getResponse(accessCode: "code", UDID: "udid", completion: { result in
// Do whatever you need to do with the dictionary result
}
Also, I'd recommend you to change your NSDictionary with a swift Dictionary.
This is what the API returns as a response
{
AccessCode = 00000000;
Client = "0000 - My Company Name";
EmailAddress = "brandon#brandonthomas.me";
FirstName = Brandon;
Found = 1;
LastName = Thomas;
Status = A;
UDIDregistered = 1;
}
And this is what calls the function. I am calling at after clicking a button after an access code is being entered in a text field.
#IBAction func StartWizard(_ sender: UIButton) {
//Store entered access code
let accessCode = AccessCodeField.text!
var accessCodeFound: Bool? = nil
//Call API to validate Access Code
getResponse(accessCode:accessCode, UDID:myDeviceUDID) { result in
accessCodeFound = result["Found"] as! Bool
print("Value of Found during function:")
print(accessCodeFound)
//accessCodeFound = true
}
//If access code is valid, go to License view
print("Value of Found after function:")
print(accessCodeFound)
//accessCodeFound = nil ???
//it seems the value is getting reset after the function completes
if accessCodeFound == true{
//Load License View
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let licenseController = storyboard.instantiateViewController(identifier: "LicenseViewPanel")
self.show(licenseController, sender: Any?.self)
}
}
I'm gonna start with I'm currently learning swift + iOS so I'm by no means an experienced developer or one for that matter.
My goal is to separate any network calls that are currently done in my view controller to a dedicated class outside of it.
In this view controller i have a IBAction with the following code inside of it:
let config = URLSessionConfiguration.default
let session = URLSession(configuration: config)
session.dataTask(with: loginRequest) {
(data, response, error) in
guard let _ = response, let data = data else {return}
do {
let apiData = try NetworkManager.shared.decoder.decode(ApiData.self, from: data)
let token = apiData.data?.token
let saveToken: Bool = KeychainWrapper.standard.set(token!, forKey: "token")
DispatchQueue.main.async {
self.showOrHideActivityIndicator(showOrHide: false)
self.showHomeScreen()
}
} catch let decodeError as NSError {
print("Decoder error: \(decodeError.localizedDescription)\n")
return
}
}.resume()
What I want, or I think I want to achieve is something like this:
let apiData = "somehow get it from outside"
Then when apiData has info stored in it, execute this next bit of code:
let token = apiData.data?.token
let saveToken: Bool = KeychainWrapper.standard.set(token!, forKey: "token")
DispatchQueue.main.async {
self.showOrHideActivityIndicator(showOrHide: false)
self.showHomeScreen()
}
How would I achieve this? Thank you.
You can try
class API {
static func userLoginWith(email:String,password:String,completion:#escaping(_ token:String?) -> ()) {
let config = URLSessionConfiguration.default
let session = URLSession(configuration: config)
session.dataTask(with: loginRequest) {
(data, response, error) in
guard let _ = response, let data = data else { completion(nil) ; return }
do {
let apiData = try NetworkManager.shared.decoder.decode(ApiData.self, from: data)
completion(apiData.data?.token)
} catch {
print("Decoder error: ",error")
completion(nil)
}
}.resume()
}
}
Inside the VC
API.userLoginWith(email:<##>,password:<##>) { (token) in
if let token = token {
let saveToken: Bool = KeychainWrapper.standard.set(token!, forKey: "token")
DispatchQueue.main.async {
self.showOrHideActivityIndicator(showOrHide: false)
self.showHomeScreen()
}
}
}
I'm attempting to print/dump and array of type Music outside of a function it's created in. I can successfully dump the musicItems array inside of the getMusicData function but when I set the musicItems array outside of the scope, it won't print anything. What am I doing wrong with the scope here? I have a feeling it's super simple but I just can't figure it out. Thanks in advance for taking the time to read this.
edit: It's giving me "0 elements" in the console when I attempt to dump the musicItems array in the ViewController class. Well, the function is in the same class as well so I guess I don't know what to call the first array. The parent array?
struct MusicResults: Decodable {
let results: [Music]?
}
struct Music: Decodable {
let trackName: String?
let collectionName: String?
let artworkUrl30: String?
}
class ViewController: UITableViewController, UISearchBarDelegate {
var musicItems: [Music] = []
#IBAction func musicButton(_ sender: UIBarButtonItem) {
getMusicData()
dump(musicItems)
}
Here is the function.
func getMusicData() {
var musicItems: [Music] = []
guard let searchTerm = searchString else {return}
let newString = searchTerm.replacingOccurrences(of: " ", with: "+", options: .literal, range: nil)
let jsonUrlString = "https://itunes.apple.com/search?media=music&term=\(newString)"
guard let url = URL(string: jsonUrlString) else { return }
URLSession.shared.dataTask(with: url) { (data, response, err) in
guard let data = data else { return }
do {
let music = try JSONDecoder().decode(MusicResults.self, from: data)
for results in music.results! {
// print(results.trackName!)
musicItems.append(results)
}
//dump(musicItems)
self.musicItems = musicItems
// DispatchQueue.main.async {
// self.tableView.reloadData()
// }
} catch let jsonErr {
print("Error serializing json:", jsonErr)
}
}.resume()
}
Fixed Code
#IBAction func musicButton(_ sender: UIBarButtonItem) {
getMusicData {
music in
dump(music)
}
function:
func getMusicData(completionHandler: #escaping (_ music: [Music]) -> ()) {
...
let music = try JSONDecoder().decode(MusicResults.self, from: data)
for results in music.results! {
musicItems.append(results)
}
completionHandler(musicItems)
...
Your 'getMusicData' function is asynchronous which means that when it executes, it queues data task in a background queue and proceeds the execution and since there are no more institutions it simply returns control to its calling site - 'musicButton()' action, which in its turn executes the next instruction - prints the 'musicItems' array which might (and most likely, is) still not populated as the network call haven’t yet completed. One of the options that you have here is to pass a completion block to your 'getMusicData' function, that runs it after data task gets the results.
Another option is to use Property Observers
var musicItems: [Music] = [] {
didSet {
dump(self.musicItems)
/// This is where I would do the...
// DispatchQueue.main.async {
// self.tableView.reloadData()
// }
}
}
and then
func getMusicData() {
guard let searchTerm = searchString else { print("no search"); return }
let newString = searchTerm.replacingOccurrences(of: " ", with: "+", options: .literal, range: nil)
let jsonUrlString = "https://itunes.apple.com/search?media=music&term=\(newString)"
guard let url = URL(string: jsonUrlString) else { print("url error"); return }
URLSession.shared.dataTask(with: url) { (data, response, err) in
guard let data = data else { print(err ?? "unknown"); return }
do {
let music = try JSONDecoder().decode(MusicResults.self, from: data)
if let results = music.results {
self.musicItems.append(contentsOf: results)
}
} catch let jsonErr {
print("Error serializing json:", jsonErr)
}
}.resume()
}
I got a source code from a github page written in swift and implementing GoogleMaps. I now want to refactor the codes to use Alamofire and SwiftyJSON so that I can improve the code but I got confused because through my learning of swift I used Alamofire and swiftyJSON for every networking process so I am confused currently. the code below
typealias PlacesCompletion = ([GooglePlace]) -> Void
typealias PhotoCompletion = (UIImage?) -> Void
class GoogleDataProvider {
private var photoCache: [String: UIImage] = [:]
private var placesTask: URLSessionDataTask?
private var session: URLSession {
return URLSession.shared
}
let appDelegate = UIApplication.shared.delegate as! AppDelegate
func fetchPlacesNearCoordinate(_ coordinate: CLLocationCoordinate2D, radius: Double, types:[String], completion: #escaping PlacesCompletion) -> Void {
var urlString = "https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=\(coordinate.latitude),\(coordinate.longitude)&radius=\(radius)&rankby=prominence&sensor=true&key=\(appDelegate.APP_ID)"
let typesString = types.count > 0 ? types.joined(separator: "|") : "food"
urlString += "&types=\(typesString)"
urlString = urlString.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed) ?? urlString
guard let url = URL(string: urlString) else {
completion([])
return
}
if let task = placesTask, task.taskIdentifier > 0 && task.state == .running {
task.cancel()
}
DispatchQueue.main.async {
UIApplication.shared.isNetworkActivityIndicatorVisible = true
}
placesTask = session.dataTask(with: url) { data, response, error in
var placesArray: [GooglePlace] = []
defer {
DispatchQueue.main.async {
UIApplication.shared.isNetworkActivityIndicatorVisible = false
completion(placesArray)
}
}
guard let data = data,
let json = try? JSON(data: data, options: .mutableContainers),
let results = json["results"].arrayObject as? [[String: Any]] else {
return
}
results.forEach {
let place = GooglePlace(dictionary: $0, acceptedTypes: types)
placesArray.append(place)
if let reference = place.photoReference {
self.fetchPhotoFromReference(reference) { image in
place.photo = image
}
}
}
}
placesTask?.resume()
}
func fetchPhotoFromReference(_ reference: String, completion: #escaping PhotoCompletion) -> Void {
if let photo = photoCache[reference] {
completion(photo)
} else {
let urlString = "https://maps.googleapis.com/maps/api/place/photo?maxwidth=200&photoreference=\(reference)&key=\(appDelegate.APP_ID)"
guard let url = URL(string: urlString) else {
completion(nil)
return
}
DispatchQueue.main.async {
UIApplication.shared.isNetworkActivityIndicatorVisible = true
}
session.downloadTask(with: url) { url, response, error in
var downloadedPhoto: UIImage? = nil
defer {
DispatchQueue.main.async {
UIApplication.shared.isNetworkActivityIndicatorVisible = false
completion(downloadedPhoto)
}
}
guard let url = url else {
return
}
guard let imageData = try? Data(contentsOf: url) else {
return
}
downloadedPhoto = UIImage(data: imageData)
self.photoCache[reference] = downloadedPhoto
}
.resume()
}
}
}
any help to refactor the codes to use Alamofire and swiftyJSON would be appreciated.
Both Alamofire and SwiftyJSON have pretty decent instructions, and there are plenty of examples online to look for. However, this would be a decent starting point - you need to replace your session.dataTask and session.downloadTask with Alamofire methods. For example, instead of:
session.downloadTask(with: url) { url, response, error in
var downloadedPhoto: UIImage? = nil
defer {
DispatchQueue.main.async {
UIApplication.shared.isNetworkActivityIndicatorVisible = false
completion(downloadedPhoto)
}
}
guard let url = url else {
return
}
guard let imageData = try? Data(contentsOf: url) else {
return
}
downloadedPhoto = UIImage(data: imageData)
self.photoCache[reference] = downloadedPhoto
}
.resume()
use this skeleton and implement your models and logic:
Alamofire
.request(url)
.responseJSON { dataResponse in
switch dataResponse.result {
case .success:
guard let json = JSON(dataResponse.data) else {
return
}
// Continue parsing
case .failure(let error):
// Handle error
print("\(error)")
}
}