Hello i have a CollectionViewCell file, where i am trying to call public func configure cell.
Here is func
public func configureCell(with cellViewModel: CellViewModel) {
self.articleTitleLabel.text = cellViewModel.title
if let data = cellViewModel.imageData {
self.articleImage.image = UIImage(data: data)
} else if let url = cellViewModel.urlToImage {
URLSession.shared.dataTask(with: url) { [weak self] data, _, error in
guard let data = data && error == nil else { return }
cellViewModel.imageData = data
DispatchQueue.main.async {
self.articleImage.image = UIImage(data: data)
}
}
}
}
here is model
struct CellViewModel {
let title: String
let urlToImage: String?
let imageData: Data? = nil
init(title: String, urlToImage: String) {
self.title = title
self.urlToImage = urlToImage
}
}
But i got error:
No exact matches in call to instance method 'dataTask'
Why? How can i fix my code?
urlToImage is of type String but the datatask needs an argument of type URL.
You can use:
else if let stringurl = cellViewModel.urlToImage, let url = URL(string: stringurl){
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 am working on an app that Decode a JSON file and creates three variables out of the function: Status,emptySlots,freeBikes. I want to assign these values to labels. However, no matter what I do, I was unable to get any output with any method.
The function code:
func getBikeData(stationName:String){
if let url = URL(string: "https://api.citybik.es//v2/networks/baksi-bisim"){
let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let dataResponse = data, error == nil else {
print(error?.localizedDescription ?? "Response Error")
return
}
do {
//here dataResponse received from a network request
let jsonResponse = try JSONSerialization.jsonObject(with:
dataResponse, options: [])
print(jsonResponse) //Response result
do {
//here dataResponse received from a network request
let decoder = JSONDecoder()
//Decode JSON Response Data
let model = try decoder.decode(ResponseJSON.self, from: dataResponse)
print(model)//Output - 1221
if let station = model.network.stations.first(where: { $0.name == stationName }) {
//get the properties of station here as per requirement
let emptySlots: Int = station.empty_slots
let freeBikes: Int = station.free_bikes
let Status: String = station.extra.status
print(emptySlots, freeBikes, Status)
}
}
catch let parsingError {
print("Error", parsingError)
}
} catch let parsingError {
print("Error", parsingError)
}
}
task.resume()
}
}
Any help is gladly appreciated. I have already tried to return the variables, and using completion block.
ResponseJSON Struct:
struct ResponseJSON: Codable {
let network: Stations
}
One way to solve this is to use a closure. To simplify things create a struct that holds the values
struct BikeResponse {
let status: String
let freeBikes: Int
let emptySlots: Int
}
And then modify your function declaration to
func getBikeData(stationName:String, completion: (BikeResponse)->(Void)){
and then after the decoding you call the completion handler
if let station = model.network.stations.first(where: { $0.name == stationName }) {
let response = BikeResponse(status: station.extra.status,
freeBikes: station.free_bikes,
emptySlots: station.empty_slots)
completion(response)
And then in your completion code you can assign the values to your labels
getBikeData(stationName: "ABC") { response in
DispatchQueue.main.async {
someLabel.text = response.status
//...
}
}
Simplest solution:
if let station = model.network.stations.first(where: { $0.name == stationName }) {
DispatchQueue.main.async {
self.emptySlotsLabel.text = String(station.empty_slots)
self.freeBikesLabel.text = String(station.free_bikes)
self.statusLabel.text = station.extra.status
}
}
emptySlotsLabel, freeBikesLabel and statusLabel are the labels, change the names to the real names
you need to add completion handler to you function. Because you are trying to make async query.
After calling getbikedata func you can assign value to your labels.
Sample code looks like this:
func getBikeData(stationName:String, completion: #escaping (Station) -> Void) {
// ... your code here
if let station = model.network?.stations?.first(where: { $0.name == stationName }) {
//get the properties of station here as per requirement
// let emptySlots: Int = station.emptySlots!
// let freeBikes: Int = station.freeBikes!
// let Status: String = (station.extra?.status)!.rawValue
completion(station)
}
// ... other your code here
}
And usage:
getBikeData(stationName: stationName) { (station) in
print(station)
// For example
label.text = station.emptySlots
}
I run this code in viewDidLoad, but Profile.currentProfile does not have the photoUrl yet, so it is nil and this code never runs
private func getProfilePicture() {
if let photoURLString = Profile.currentProfile?.photoUrl {
if let photoURL = URL(string: photoURLString) {
if let photoData = try? Data(contentsOf: photoURL) {
self.profilePhotoView.image = UIImage(data: photoData)
self.letsGoButton.isEnabled = true
}
}
} else {
self.profilePhotoView.image = UIImage(named: "default-profile-icon")
}
}
How can I wait until the photoUrl is not nil, then run this code? Thanks
Rik
(edit) this is how profile is set. This is called before the viewController is instantiated.
func copyProfileFieldsFromFB(completionHandler: #escaping ((Error?) -> Void)) {
guard AccessToken.current != nil else { return }
let request = GraphRequest(graphPath: "me",
parameters: ["fields": "email,first_name,last_name,gender, picture.width(480).height(480)"])
request.start(completionHandler: { (_, result, error) in
if let data = result as? [String: Any] {
if let firstName = data["first_name"] {
Profile.currentProfile?.firstName = firstName as? String
}
if let lastName = data["last_name"] {
Profile.currentProfile?.lastName = lastName as? String
}
if let email = data["email"] {
Profile.currentProfile?.email = email as? String
}
if let picture = data["picture"] as? [String: Any] {
if let imageData = picture["data"] as? [String: Any] {
if let url = imageData["url"] as? String {
Profile.currentProfile?.photoUrl = url
}
}
}
}
completionHandler(error)
})
}
Normally, you'll want to use completion handlers to keep track of asynchronous activities. So in your viewDidLoad() you could call something like
Profile.currentProfile?.getPhotoURL { urlString in
if let photoURL = URL(string: photoURLString) {
if let photoData = try? Data(contentsOf: photoURL) {
self.profilePhotoView.image = UIImage(data: photoData)
self.letsGoButton.isEnabled = true
}
}
}
And on your Profile class it would look something like this:
func getPhotoURL(completion: #escaping (urlString) -> Void) {
// get urlString
completion(urlString)
}
You can add private var profileUrl and use didSet observing with it:
... //e.g. your controller
private var profileUrl: URL? {
didSet {
if let url = profileUrl {
getProfilePicture(from: url)// update your func
}
}
}
I'm trying to get JSON but it shows an occurred issue
Line starting with if let deliveryObject
How to get rid of the problem?
code:
struct Tracking {
let receiver: String
let placeOfMail: String
let indexOfMail: Double
init(json:[String:Any]) throws {
guard let receiver = json["name"] as? String else {
throw SerializationError.missing("Receiver data has been missed")
}
guard let placeOfMail = json ["address"] as? String else {
throw SerializationError.missing("Place of delivery has been missed")
}
guard let indexOfMail = json ["postindex"] as? Double else {
throw SerializationError.missing("Index of postmail has been missed")
}
self.receiver = receiver
self.placeOfMail = placeOfMail
self.indexOfMail = indexOfMail
}
static let basePath = "https://track.kazpost.kz/api/v2/"
static func deliveryData (withTrackid trackid:String, completion: #escaping ([Tracking]) -> ()){
let url = basePath + trackid
let request = URLRequest(url: URL(string: url)!)
let task = URLSession.shared.dataTask(with: request) { (data: Data?, response : URLResponse?, error: Error?) in
var deliveryArray: [Tracking] = []
if let data = data {
do {
if let json = try JSONSerialization.jsonObject(with: data, options:[]) as? [String:Any] {
if let deliveryInformation = json ["delivery"] as? [String:Any] {
if let deliveryPlace = deliveryInformation ["address"] as? [String:Any] {
for dataPoint in deliveryPlace {
if let dataPointValue = dataPoint.value as? [String: AnyObject],
let deliveryObject = try Tracking(json: dataPointValue) {
deliveryArray.append(deliveryObject)
}
}
}
}
}
}catch {
print(error.localizedDescription)
}
completion(deliveryArray)
}
}
task.resume()
}
}
This question already has answers here:
Run code only after asynchronous function finishes executing
(2 answers)
Closed 5 years ago.
Im trying to wait for the function to process in order to show my image. I have try many things but none of this worked. I know this is an async function and basically i have to wait in order to get the right values but I dont know how to fix this function right here. I hope you can help me out. Thank you!
func createListProductsGood(Finished() -> void) {
refProducts.child("Products").queryOrderedByKey().observe(.childAdded, with: { snapshot in
let prod = snapshot.value as! NSDictionary
let active = snapshot.key
let rejected = prod["NotInterested"] as! String
let photoURL = prod["photoURL"] as! String
var findit = false
// print(rejected)
if (rejected != self.userUID){
//print(active)
if rejected.contains(","){
var pointsArr = rejected.components(separatedBy: ",")
for x in pointsArr{
if x.trimmingCharacters(in: NSCharacterSet.whitespaces) == self.userUID {
// print("dont show")
findit = true
return
}
}
if (findit == false){
if let url = NSURL(string: photoURL) {
if let data = NSData(contentsOf: url as URL) {
self.ProductId = active
self.productPhoto.image = UIImage(data: data as Data)
}}
}
}else{
print(active)
if let url = NSURL(string: photoURL) {
if let data = NSData(contentsOf: url as URL) {
self.ProductId = active
self.productPhoto.image = UIImage(data: data as Data)
}}
}
}
})
finished()
}
Edited:
This is how my viewDidLoad looks like:
override func viewDidLoad() {
super.viewDidLoad()
setAcceptedOrRejected()
createListProductsGood{_ in
}
}
func createListProductsGood(finished: #escaping (_ imageData: Data) -> Void) {
refProducts.child("Products").queryOrderedByKey().observe(.childAdded, with: { snapshot in
let prod = snapshot.value as! NSDictionary
let active = snapshot.key
let rejected = prod["NotInterested"] as! String
let photoURL = prod["photoURL"] as! String
var findit = false
// print(rejected)
if (rejected != self.userUID){
//print(active)
if rejected.contains(","){
var pointsArr = rejected.components(separatedBy: ",")
for x in pointsArr{
if x.trimmingCharacters(in: NSCharacterSet.whitespaces) == self.userUID {
// print("dont show")
findit = true
return
}
}
if (findit == false){
if let url = NSURL(string: photoURL) {
if let data = NSData(contentsOf: url as URL) {
self.ProductId = active
DispatchQueue.main.async {
self.productPhoto.image = UIImage(data: data as Data)
}
}}
}
}else{
print(active)
if let url = NSURL(string: photoURL) {
if let data = NSData(contentsOf: url as URL) {
self.ProductId = active
DispatchQueue.main.async {
self.productPhoto.image = UIImage(data: data as Data)
}
}}
}
}
})
}
This is my second method:
func setAcceptedOrRejected() {
refProducts.child("Products").queryOrderedByKey().observe(.childAdded, with: { snapshot in
let prod = snapshot.value as! NSDictionary
if self.ProductId == snapshot.key{
self.texto = prod["NotInterested"] as! String
self.refProducts.child("Products").child(self.ProductId).updateChildValues(["NotInterested": self.texto + ", " + self.userUID])
} })
}
You should change:
func createListProductsGood(Finished() -> void) {
to:
func createListProductsGood(finished: #escaping (_ something: SomeType) -> Void) {
or to be more specific:
func createListProductsGood(finished: #escaping (_ imageData: Data) -> Void) {
then wherever in your function you get the image, you call
finished(imageData)
so you can pass the imageData through a closure to where its needed.
then you call this function like this:
createListProductsGood{ imageData in
...
let image = UIImage(data: imageData)
// update UI from main Thread:
DispatchQueue.main.async {
self.productPhoto.image = image
}
}
Also:
it's not convention to use Finished(), you should use finished()
using void is wrong. You must use Void or ()
If you're having problems with closures and completionHandlers, I recommend you first try getting your hands dirty with a simple UIAlertController. See here. Try creating an action with a closure, e.g. see here
EDIT :
Thanks to Leo's comments:
func createListProductsGood(finished: #escaping(_ imageData: Data?, MyError?) -> Void) {
let value: Data?
let error = MyError.someError("The error message")
refProducts.child("Products").queryOrderedByKey().observe(.childAdded, with: { snapshot in
let prod = snapshot.value as! NSDictionary
let active = snapshot.key
let rejected = prod["NotInterested"] as! String
let photoURL = prod["photoURL"] as! String
var findit = false
// print(rejected)
if (rejected != self.userUID){
//print(active)
if rejected.contains(","){
var pointsArr = rejected.components(separatedBy: ",")
for x in pointsArr{
if x.trimmingCharacters(in: NSCharacterSet.whitespaces) == self.userUID {
// print("dont show")
findit = true
return
}
}
if (findit == false){
if let url = NSURL(string: photoURL) {
if let data = NSData(contentsOf: url as URL) {
self.ProductId = active // REMOVE
self.productPhoto.image = UIImage(data: data as Data) // REMOVE
finished(data, nil) //ADD
}else{
finished(nil,error) //ADD
}
}
}
}else{
print(active)
if let url = NSURL(string: photoURL) {
if let data = NSData(contentsOf: url as URL) {
self.ProductId = active // REMOVE
self.productPhoto.image = UIImage(data: data as Data) // REMOVE
finished(data,nil) //ADD
}else{
finished(nil,error) //ADD
}
}
}
}
})
}
And then you call it like:
createListProductsGood { imageData, error in guard let value = imageData, error == nil else { // present an alert and pass the error message return }
...
let image = UIImage(data: imageData)
// update UI from main Thread:
DispatchQueue.main.async {
self.ProductId = active
self.productPhoto.image = image } }
Basically this way the createListProductsGood takes in 2 closures, one for if the image is present, another for if an error was returned.