hello i'm new to swift and I have responseJson from alamofire consist of jsonArray contain jsonObjects like this
[{"id":"1","name":"person1"},{"id":"2","name":"person2"}]
how i can parse it into array of this custom model
class Person {
var name : String
var id : String
}
i've done a much searching but can't find case identical to mine and i can't use Codable because i'm using xcode 8 and not able to upgrade my xcode version to 9 now
I'm getting the response like this
Alamofire.request(url).responseJSON{ response in
if(response.result.isSuccess)
{
if let jsonarray = response.result.value as? [[String: Any]]
{
//what to do here ?
}
}
}
if let jsonarray = response.result.value as? [[String: Any]]{
//what to do here ?
var persons:[Person] = []
for userDictionary in jsonarray{
guard let id = userDictionary["id"] as? String, let name = userDictionary["name"] as? String else { continue }
persons.append(Person(id, name))
}
//Persons complete.
}
Use guard else for the required variables.
If there are additional variables that could be optional, like var age:Int? in Person, you could do like this:
for userDictionary in jsonarray{
guard let id = userDictionary["id"] as? String, let name = userDictionary["name"] as? String else { continue }
let age = userDictionary["age"] as? Int
persons.append(Person(id, name, age))
}
#Tony,
In swift4 you can codable protocol to parsing the JSON that helps in writing generic code. Suppose if in future requirement came to add dob than its very simple.
And in swift3 you can use object mapper class for same.
If you need more help than please let me know.
Related
I am new to iOS development and been trying to jump into swift straight away. I am trying to work with APIs and trying to learn myself. I've build this test Collection view along with the model to get the data however when I run the app I get a crash. Been trying to find a solution with no luck.
I've seen few that have the same crash however mostly due to a xib file which I am not using. I am building the app solely in code.
AlbumId
import UIKit
class AlbumId: NSObject {
var albumId: NSNumber?
static func fetchAlbums() {
let urlString = "https://jsonplaceholder.typicode.com/photos"
let url = URL(string: urlString)
URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil {
print(error ?? "")
return
}
do {
let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers)
var albums = [Album]()
for dict in json as! [Any] {
let album = Album(dictionary: dict as! [String: Any])
album.setValuesForKeys(dict as! [String : Any])
albums.append(album)
}
} catch let err {
print(err)
}
}.resume()
}
}
Album
class Album: NSObject {
var id: NSNumber?
var title: String?
var url: String?
var thumbnailUrl: String?
init(dictionary: [String: Any]) {
super.init()
id = dictionary["id"] as? NSNumber
title = dictionary["title"] as? String
url = dictionary["url"] as? String
thumbnailUrl = dictionary["thumbnailUrl"] as? String
}
}
Your class Album does not have a property called albumId which means that it is not KVC compliant for that key.
It seems your JSON response has a key "albumId", but since your class is not KVC-compliant (it doesn't have an "albumId" property) using setValuesForKeys fails because setValuesForKeys requires that the instance must be KVC compliant for all of the keys in the dictionary.
Without a little knowledge regarding the JSON response, we can only make recommendations based on assumptions.
Your options are:
Change the property "id" to "albumId" on class Album
Change your API so the JSON key is simply "id"
Override setValueForKey and redirect "albumId" to your "id" property.
The error occurs because the model does not contain the property albumId.
Calling the KVC method setValuesForKeys is redundant anyway since you are initializing the object from the dictionary. There are only a few rare cases in Swift where KVC is useful. This is none of them. And inheritance from NSObject is actually not needed either.
The received JSON has id and albumId keys, so add the latter to the model and use Int rather than NSNumber. This code uses non-optional constants (let) with default values empty string / 0
class Album {
let albumId : Int
let id: Int
let title: String
let url: String
let thumbnailUrl: String
init(dictionary: [String: Any]) {
albumId = dictionary["albumId"] as? Int ?? 0
id = dictionary["id"] as? Int ?? 0
title = dictionary["title"] as? String ?? ""
url = dictionary["url"] as? String ?? ""
thumbnailUrl = dictionary["thumbnailUrl"] as? String ?? ""
}
}
Now populate the albums array, as always .mutableContainers is completely meaningless in Swift
if let json = try JSONSerialization.jsonObject(with: data!) as? [[String: Any]] else { return }
var albums = [Album]()
for dict in json {
let album = Album(dictionary: dict)
albums.append(album)
}
or in a swiftier way
var albums = json.map { Album(dictionary: $0) }
I have the following data I received from Firebase. I have made my snapshotValue a NSDictionary.
self.ref.child("users").child(facebookID_Firebase as! String).observeSingleEvent(of: .value, with: { (snapshot) in
let snapshotValue = snapshot.value as? NSDictionary
print(snapshotValue, "snapshotValue")
//this line of code doesn't work
//self.pictureURL = snapshot["picture"]["data"]["url"]
}) { (error) in
print(error.localizedDescription)
}
I tried How do I manipulate nested dictionaries in Swift, e.g. JSON data? , How to access deeply nested dictionaries in Swift , and other solutions yet no luck.
How do I access the url value inside the data key AND the picture key?
I can make another reference in Firebase and get the value, but I'm trying to save another request. 😓
When you refrence to a key of a Dictionary in swift you get out an unwrapped value. This means it can be nil. You can force unwrap the value or you can use pretty if let =
this should probably work.
if let pictureUrl = snapshot["picture"]["data"]["url"] {
self.pictureURL = pictureUrl
}
Try using :-
if let pictureDict = snapshot.value["picture"] as? [String:AnyObject]{
if let dataDict = pictureDict.value["data"] as? [String:AnyObject]{
self.pictureURL = dataDict.value["url"] as! String
}
}
Inline dictionary unwrapping:
let url = ((snapshot.value as? NSDictionary)?["picture"] as? NSDictionary)?["url"] as? String
You can use the following syntax, that is prettier:
if let pictureDict = snapshot.value["picture"] as? [String:AnyObject],
let dataDict = pictureDict.value["data"] as? [String:AnyObject] {
self.pictureURL = dataDict.value["url"] as! String
}
}
let result = try?NSJSONSerialization.JSONObjectWithData(data,options:.MutableContainers)
How to take values from given JSON in swift2.3
({
FirstName:"sample"
LastName:"Data"
},
{
FirstName:"sample1"
LastName:"Data1"
})
How can I take value from first name and add to array swift 2.3 and Xcode8
Ok, try this with json is the json dictionary
let firstname = json["FirstName"] as! String
The following code converts your given json into string then uses NSJSONSerialization to parse your json and finally print the values of FirstName and Lastname
let jsonString = "[{\"FirstName\":\"sample\",\"LastName\":\"Data\"},{\"FirstName\":\"sample1\",\"LastName\":\"Data1\"}]"
if let serializedJsonArray = try? NSJSONSerialization.JSONObjectWithData(jsonString.dataUsingEncoding(NSUTF8StringEncoding)!, options: .MutableContainers),
let parsedJsonArray = serializedJsonArray as? [[String:AnyObject]]{
for jsonArray in parsedJsonArray {
if let firstName = jsonArray["FirstName"] as? String{
print(firstName)
}
if let lastName = jsonArray["LastName"] as? String{
print(lastName)
}
}
}
Hope this helps.
Im using Swift 3 and Alamofire 4.0. I am able to print out the entire response but I am having trouble looping through and printing out each value. I am getting a " Type 'NSFastEnumerationIterator.Element' (aka 'Any') has no subscript members when I try to print out 'title' below. Any help is greatly appreciated.
Alamofire.request(url).responseJSON { response in
if let dict = response.result.value as? Dictionary<String, AnyObject> {
if let datas = dict["data"] as? NSArray{
for data in datas{
print("DEVELOPER: \(data)")
if let title = data["myTitle"] as? String{
print(title)
}
}
}
}
}
Just use native Swift Array. Use always Swift native types unless you have absolutely no choice. NSArray lacks type information so the compiler cannot infer that the array contains dictionaries.
if let datas = dict["data"] as? [[String:Any]] {
Sometimes you wanna keep your data as structured, all you have to do is check for the dictionary itself while in loop like the following:
for apple in apples {
if let _ = apple as? [String:AnyObject] {
// do whatever you like here
}
}
While fetching data from api I can get response either array of products or dictionary with error for e.g.
If everything went right api sends array of products as:
[
"Product1":
{
name = "someting",
price = 100,
discount = 10%,
images = [image1,image2]
},
"Product2":
{
name = "someting",
price = 100,
discount = 10%,
images = [image1,image2]
}
]
But if some error occur it sends dictionary with error message and code as:
{
error_message = "message"
error_code = 202
}
I am using this code to convert JSON data to array:
do {
let jsonDict = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers) as! NSArray{
//Some code....
} catch let error as NSError {
print("JSON Error: \(error.localizedDescription)")
}
but if I get error as dictionary it crash.
Problems:
1. How to know whether received data is an array or dictionary ?
2. Some time even key or value can be missing so checking for value it becomes very lengthy code like:
if let productsArray = jsonObject as? NSArray{
if let product1 = productsArray[0] as? NSDictionary{
if let imagesArray = product1["image"] as? NSArray{
if let imageUrl = imagesArray[0] as? String{
//Code ....
}
}
}
}
I read about guard keyword to reduce if condition but I don't have clear idea how to use here.
Problem 1:
For try catch , add an if let for casting the object as NSDictionary or NSArray like :
do {
let jsonObject = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers)
if let jsonDict = jsonObject as? NSDictionary {
// Do smthg.
}
if let jsonArray = jsonObject as? NSArray {
// Do smthg.
}
}catch {
//...
}
For Problem 2:
I think guard won't help you . It needs smthg like return / break in its else statement. If you don't want to throw your methods if one of your values isn't available you have to use this lengthy if let code style.
Maybe in your case best practice would be setting up a Data Model for Product with optional properties.
Class product {
var name:String?
var image:[NSData]? // maybe UIImage or smthg.
var price:Int?
var discount:Int?
init(jsonDic:NSDictionary){
// if it's not there it would be nil
self.name = jsonDic["name"] as? String
self.image = jsonDic["image"] as? NSArray
self.discount = jsonDic["discount"] as? Int
self.price = jsonDic["price"] as? Int
}
}
Now you can load those models with your data without the if let etc..
But if you wanna read those values you have to use the if let for checkin if its not nil.
For init in your case it should be something like this:
Add this into the if let statement of the do catch block ( ... as? NSArray // DO smthg. )
for item in jsonArray {
guard let jsonDic = item as? NSDictionary else { return }
// if you dont know every key you can just iterate through this dictionary
for (_,value) in jsonDic {
guard let jsonDicValues = value as? NSDictionary else { return }
productArray.append(Product(jsonDic: jsonDicValues)
}
}
As i said , know you got the whole if let stuff when reading from the model an not when writing ( reading the json )
You have a few things going on here, one, I would analyze your server's http response status code and only attempt to process data if you received a status code indicating you will have good data
// In practical scenarios, this may be a range
if statusCode != 200 {
// Handle a scenario where you don't have good data.
return
}
Secondly, I'd guard against the response, it looks like you have named it "data" like so:
guard let receivedData = data else {
return
}
From this point on, you can use the receivedData constant.
Here'd I'd attempt to use NSJSONSeralization, like you do, but by casting it into a Swift dictionary, like so:
if let responseDictionary = try? NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers) as? [String:AnyObject] {
// Here you can try to access keys on the response
// You can try things like
let products = responseDictionary?["products"] as? [[String:AnyObject]]
for product in products {
let productName = product["name"] as? String
if productName == nil {
continue
}
let newProduct = Product(name: productName)
// Do something with newly processed data
}
}
I tried to be general and also show you a guard example.
first of all I recommend using SwiftyJSON pod or the class straight into your Xcode, it works like a charm and you won't need to cast things down to figure whether you have a string or a dictionary or whatever. It is gold.
Once you've got your JSON, you can use this recursive function I created that does exactly what you need. It turns any Json into a dictionary. I mostly use it to save data into Firebase, without having to parse everything.
After you have imported SwiftyJSON into your project and added import SwiftyJSON to your Swift file you can:
//JSON is created using the awesome SwiftyJSON pod
func json2dic(_ j: JSON) -> [String:AnyObject] {
var post = [String:AnyObject]()
for (key, object) in j {
post[key] = object.stringValue as AnyObject
if object.stringValue == "" {
post[key] = json2dic(object) as AnyObject
}
}
return post
}
let json = JSON(value) // Value is the json structure you received from API.
var myDictionary = [String:AnyObject]()
myDictionary = json2dic(json)
You can catch the class of your response. If your response is kind of class dictionary, assign it as dictionary else if your response is kind of class array, assign it to array. Good luck.