So i received some json data from a server now am trying to save it as an array so i can populate a tableview with it but am having a trouble doing it here is my code :
class UserInfo : UIViewController{
var main = ""
session.dataTask(with: url) { (data, response, error) in
if let response = response {
print (response)
}
if let data = data {
let json = (try? JSONSerialization.jsonObject(with: data, options: []))
print(json)
guard let array = json as? [Any] else {return}
for info in array {
guard let infoDict = info as? [String : Any] else{return}
//there is a declared var called main
//main is the one i want save as an array, currently its a variable. i tried to save it as an array by using as! Array but i get error
self.main = infoDict["Title"] as! String
print (self.main)
}
}
}.resume()
}
First you have to declare ary outside of the request scope. Then you have to store your data in the same ary.
var ary: NSMutableArray = NSMutableArray()
session.dataTask(with: url) { (data, response, error) in
if let response = response {
print (response)
}
if let data = data {
let json = (try? JSONSerialization.jsonObject(with: data, options: []))
print(json)
guard let array = json as? [Any] else {return}
for info in array {
guard let infoDict = info as? [String : Any] else{return}
//there is a declared var called main
//main is the one i want save as an array, currently its a variable. i tried to save it as an array by using as! Array but i get error
self.main = infoDict["Title"] as! String
self.ary.add(self.main)
print (self.main)
}
print("Final array is :::",self.ary)
}
}.resume()
Try above code. Hope it will work for you.
Related
I am trying to parse some nested JSON retrieved through an API but am having trouble isolating specific key-value pairs. In fact, I have some confusion over the difference between the JSON data and the dictionary obtained through serialization.
To retrieve the data I am using:
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data, error == nil else {
return
}
To convert the data to a JSON dictionary, I am doing
do {
let stringDic = try JSONSerialization.jsonObject(with: data, options: []) as? [String : Any]
} catch let error {
print(error)
}
When printed, this produces nested output of the form:
Optional(["document_tone": {
"tone_categories" = (
{
"category_id" = "emotion_tone";
"category_name" = "Emotion Tone";
and so forth
My question is how can I get a unique value such as that for the key category_name?
If I try to use
let myCat = stringDic["category_name"]
Fix-it requires let document_tone = stringDic?["document_tone"] which if printed to console just prints whole dictionary over again.
Thanks in advance for any suggestions.
It's pretty easy: () is array, {} is dictionary and the compiler must know the static types of all subscripted objects:
if let documentTone = stringDic?["document_tone"] as? [String:Any],
let toneCategories = documentTone["tone_categories"] as? [[String:Any]] {
for category in toneCategories {
print(category["category_name"])
}
}
I think it's better to use Decodable
struct Root:Decodable {
let documentTone : InnerItem
}
struct InnerItem:Decodable {
let toneCategories: [BottomItem]
}
struct BottomItem:Decodable {
let categoryId: String
let categoryName: String
}
do {
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let result = try decoder.decode(Root.self, from: data)
//print all names
result.documentTone.toneCategories.forEach {print($0.categoryName) }
} catch {
print(error)
}
I'm trying to get data from a URL. It was successful. I can download and convert to a dictionary[String : Any] but response is in nested loops. I don't to how to retrieve. Can someone suggest how to get text and value in the response?
func getDataFromUrl() {
let url = URL(string: "https://maps.googleapis.com/maps/api/distancematrix/json?units=imperial&departure_time=1408046331&origins=37.407585,-122.145287&destinations=37.482890,-122.150235")
let request = NSMutableURLRequest(url: url!)
let session = URLSession.shared
request.httpMethod = "GET"
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: {(data, response, error) in
do {
let jsonData = try JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions.mutableContainers) as? [String: Any]
let destinationAddress = jsonData!["destination_addresses"]
print("Destination address \(String(describing: destinationAddress!))")
let origin_addresses = jsonData!["origin_addresses"]
print("Origin_addresses \(String(describing: origin_addresses!))")
let rows = jsonData!["rows"]
print("Rows \(String(describing: rows!))")
// Here I want to print text and value.
} catch {
// handle error
}
})
dataTask.resume()
}
The above answers work, but in my opinion the more swiftier approach is to use Codable.
class MyResponseType:Codable {
let destination_addresses:String
let rows:[MyCustomRowData]
}
class MyCustomRowData:Codable {
let elements:[MyCustomElementsData]
}
class MyCustomElementsData:Codable {
// properties here
}
Doing this, parsing the json is done like this:
let response = try? JSONDecoder().decode(MyResponseType.self, from: data)
Where the data variable is just the retrieved Data object from the request.
Initially you have to set up some boilerplate code to replicate your expected data format, but working with it is really worth it (and it makes it highly testable).
When the decode succeeds you have a perfectly typed object, it can also have optionals. It just wont decode if fields are missing or of the wrong type (which is a good thing).
Here is the way you can parse text and Value from response:
do{
if let jsonData = try JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions.mutableContainers) as? [String: Any] {
if let destinationAddress = jsonData["destination_addresses"] as? [String] {
print(destinationAddress) //["1 Hacker Way, Menlo Park, CA 94025, USA"]
}
if let origin_addresses = jsonData["origin_addresses"] as? [String] {
print(origin_addresses) //["3251 Hillview Ave, Palo Alto, CA 94304, USA"]
}
if let rows = jsonData["rows"] as? [[String: AnyObject]] {
if rows.indices.contains(0) {
if let elements = rows[0]["elements"] as? [[String: AnyObject]] {
for element in elements {
if let duration = element["duration"] as? [String: AnyObject] {
let text = duration["text"] as? String ?? ""
print(text) //17 mins
let value = duration["value"] as? Int ?? 0
print(value) //1010
}
if let distance = element["distance"] as? [String: AnyObject] {
let text = distance["text"] as? String ?? ""
print(text) //7.2 mi
let value = distance["value"] as? Int ?? 0
print(value) //11555
}
}
}
}
}
}
}catch{ //error handle
}
Use this code:
let rows = jsonData["rows"] as! Array
let element = rows[0] as! Dictionary
let elementArray = element.value(forKey: "elements")
let distance = elementArray[0].value(forKey: "distance")
let text = distance.value(forKey: "text")
print(text)
let value = distance.value(forKey: "value")
print(value)
Have been researching on the parsing for quite a bit. With plethora of information avilable for JSON nothing seems to explain how to do in a sensible way to extract information with swift 3.
This is what got so far
func getBookDetails() {
let scriptUrl = "https://www.googleapis.com/books/v1/volumes?q=isbn:9781451648546" .
let myurl = URL(string:scriptUrl)
let request = NSMutableURLRequest(url: myurl!)
request.httpMethod = "GET"
let task = URLSession.shared.dataTask(with: myurl! ) { (data, response, error) in
if error != nil{
print("THIS ERROR",error!)
return
} else{
if let mydata = data{
do{
let myJson = try (JSONSerialization.jsonObject(with: mydata, options: JSONSerialization.ReadingOptions.mutableContainers)) as AnyObject
// print("this is the MY JSON",myJson) ---> prints out the json
if let dictonary = myJson["items"] as AnyObject? {
print("the DICTONARY",dictonary) // ----> OUTPUT
if let dictonaryAA = dictonary["accessInfo"] as AnyObject? {
print("the accessInfo",dictonaryAA)
}
}
} catch{
print("this is the in CATCH")
}
} //data
}
}
task.resume()
}
}
OUTPUT :
the DICTONARY (
{
accessInfo = {
accessViewStatus = SAMPLE;
country = US;
=============
RELEVANT DATA as in https://www.googleapis.com/books/v1/volumes?
q=isbn:9781451648546"
==========================
title = "Steve Jobs";
};
}
)
Just need to parse through the json data to get the name, author and title of the book with reference to isbn.
Know there should be a better way to do things that is easily understandable to someone new into the language
You can parse the api in two ways
Using URLSession:
let rawDataStr: NSString = "data={\"mobile\":\"9420....6\",\"password\":\"56147180..1\",\"page_no\":\"1\"}"
self.parsePostAPIWithParam(apiName: "get_posts", paramStr: rawDataStr){ ResDictionary in
// let statusVal = ResDictionary["status"] as? String
self.postsDict = (ResDictionary["posts"] as! NSArray!) as! [Any]
print("\n posts count:",self.postsDict.count)
}
func parsePostAPIWithParam(apiName:NSString, paramStr:NSString,callback: #escaping ((NSDictionary) -> ())) {
var convertedJsonDictResponse:NSDictionary!
let dataStr: NSString = paramStr
let postData = NSMutableData(data: dataStr.data(using: String.Encoding.utf8.rawValue)!)
let request = NSMutableURLRequest(url: NSURL(string: "http://13.12..205.248/get_posts/")! as URL,
cachePolicy: .useProtocolCachePolicy,
timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = nil
request.httpBody = postData as Data
let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
if (error != nil) {
print(error as Any)
} else {
let httpResponse = response as? HTTPURLResponse
print(httpResponse as Any)
do{
if let convertedJsonIntoDict = try JSONSerialization.jsonObject(with: data!, options: []) as? NSDictionary {
convertedJsonDictResponse = convertedJsonIntoDict.object(forKey: apiName) as? NSDictionary
// callback for response
callback(convertedJsonDictResponse)
}
} catch let error as NSError {
print(error)
}
}
Using Alamofire
func AlamofirePOSTRequest() {
let urlString = "http://13.12..205.../get_posts/"
let para = ["data": "{\"mobile\":\"9420....6\",\"password\":\"56147180..1\",\"page_no\":\"1\"}"]
Alamofire.request(urlString, method: .post, parameters: para , headers: nil).responseJSON {
response in
switch response.result {
case .success:
print("response: ",response)
let swiftyJsonVar = JSON(response.result.value!)
if let resData = swiftyJsonVar["posts"].arrayObject {
self.postsDict = resData as! [[String:AnyObject]]
}
print("\n \n alomafire swiftyJsonVar: ",swiftyJsonVar)
break
case .failure(let error):
print(error)
}
}
}
})
dataTask.resume()
}
First of all, all JSON types are value types in Swift 3 so the most unspecified type is Any, not AnyObject.
Second of all, there are only two collection types in the JSON type set, dictionary ([String:Any]) and array ([Any], but in most cases [[String:Any]]). It's never just Any nor AnyObject.
Third of all, the given JSON does not contain a key name.
For convenience let's use a type alias for a JSON dictionary:
typealias JSONDictionary = [String:Any]
The root object is a dictionary, in the dictionary there is an array of dictionaries for key items. And pass no options, .mutableContainers is nonsense in Swift.
guard let myJson = try JSONSerialization.jsonObject(with: mydata) as? JSONDictionary,
let items = myJson["items"] as? [JSONDictionary] else { return }
Iterate through the array and extract the values for title and authors which is an array by the way. Both values are in another dictionary for key volumeInfo.
for item in items {
if let volumeInfo = item["volumeInfo"] as? JSONDictionary {
let title = volumeInfo["title"] as? String
let authors = volumeInfo["authors"] as? [String]
print(title ?? "no title", authors ?? "no authors")
The ISBN information is in an array for key industryIdentifiers
if let industryIdentifiers = volumeInfo["industryIdentifiers"] as? [JSONDictionary] {
for identifier in industryIdentifiers {
let type = identifier["type"] as! String
let isbn = identifier["identifier"] as! String
print(type, isbn)
}
}
}
}
You are doing wrong in this line
if let dictonaryAA = dictonary["accessInfo"] as AnyObject?
because dictonary here is an array not dictionary. It is array of dictionaries. So as to get first object from that array first use dictonary[0], then use accessInfo key from this.
I am attaching the code for your do block
do{
let myJson = try (JSONSerialization.jsonObject(with: mydata, options: JSONSerialization.ReadingOptions.mutableContainers)) as AnyObject
// print("this is the MY JSON",myJson) ---> prints out the json
if let array = myJson["items"] as AnyObject? {
print("the array",array) // ----> OUTPUT
let dict = array.object(at: 0) as AnyObject//Master Json
let accessInf = dict.object(forKey: "accessInfo") //Your access info json
print("the accessInfo",accessInf)
}
}
Hope this helps you.
I tried to get the location from the below JSON, but it returns response nil, can you check it once. Below URL gives the response, but I want to display location from below JSON.
let url = URL(string: "http://beta.json-generator.com/api/json/get/4ytNy-Nv7")
let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil
{
print ("ERROR")
}
else
{
if let content = data
{
do
{
//Array
let myJson = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject
print(myJson)
let val = myJson["Location"] as? NSDictionary
print("val=\(val)")
}
catch
{
}
}
}
}
task.resume()
Don't use Foundation datatypes, such as NSDictionary, when they have native Swift counterparts. You also need to cast the JSON to an array of dictionaries. However, the problem that actually caused the issue was that Location is a String and not a dictionary.
guard let myJsonArray = try JSONSerialization.jsonObject(with: content) as? [[String:Any]], let myJson = myJsonArray.first else {return}
print(myJson)
let val = myJson["Location"] as? String
print("val=\(val)")
The root object of the JSON is clearly an array of a dictionary not something (AnyObject). The value for key Location is in the first object of the array
if let myJson = try JSONSerialization.jsonObject(with: content) as? [[String:Any]], !myJson.isEmpty { // check also that the array is not empty
print(myJson)
let val = myJson[0] // get first object of the array
let location = val["Location"] as? String ?? "n/a"
print("location = \(location)")
}
You can use the following function to download your data. Further more since your array has only one object, to access multiple locations you can iterate through the array objects
func downloadData(){
let url = URL(string: "http://beta.json-generator.com/api/json/get/4ytNy-Nv7")
let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil
{
print ("ERROR")
}
else
{
if let content = data
{
do
{
let myJson = try JSONSerialization.jsonObject(with: content) as? [[String:Any]]
let object = myJson?[0]
if let location = object?["Location"] as? String{
print(location)
}
}
catch
{
}
}
}
}
task.resume()
}
You can change this part :
let myJson = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject
Into :
let myJson = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as! [AnyHashable: Any]
Then if your JSON only have one object try this to get the Location :
let obj = myJson[0]
let location = obj["Location"] as? String
print("Location \(location)")
I'm trying to pass data from a JSON response to a table view cell. I'm having problems with capturing the response values that I'm extracting in URLSession.shared.dataTask.
func callYouTubeAPIToGetAllVideos() {
let url = URL(string: "https://www.googleapis.com/youtube/v3/search?part=snippet&channelId=XYZ&maxResults=50&order=date&key=ABC")
let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil {
print(error!)
} else {
if let usableData = data {
let json = try? JSONSerialization.jsonObject(with: usableData, options: [])
if let dictionary = json as? [String: Any?] {
if let array = dictionary["items"] as? [Any] {
for object in array {
if let objectAsDictionary = object as? [String: Any?] {
if let objectWithKindAndVideoId = objectAsDictionary["id"] as? [String: String] {
if let videoId = objectWithKindAndVideoId["videoId"] {
//pass data to table cell
}
}
if let snippet = objectAsDictionary["snippet"] as? [String: Any] {
if let description = snippet["description"] {
//pass data to table cell
}
}
}
}
}
}
}
}
}
task.resume()
}
I tried appending the values to an instance variable but it didn't work.
Sorry about the messy code, this is my 1st time working with JSON in Swift.
First of all never declare a received JSON dictionary as [String:Any?]. A received dictionary value can't be nil.
Declare a custom struct Video.
struct Video {
let videoId : String
let description : String
}
Declare a data source array.
var videos = [Video]()
Parse the JSON into the array and reload the table view on the main thread.
func callYouTubeAPIToGetAllVideos() {
let url = URL(string: "https://www.googleapis.com/youtube/v3/search?part=snippet&channelId=XYZ&maxResults=50&order=date&key=ABC")
let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil {
print(error!)
} else {
do {
if let dictionary = try JSONSerialization.jsonObject(with: data!) as? [String: Any],
let array = dictionary["items"] as? [[String: Any]] {
for object in array {
if let objectWithKindAndVideoId = object["id"] as? [String: String],
let snippet = object["snippet"] as? [String: Any] {
let videoId = objectWithKindAndVideoId["videoId"] ?? ""
let description = snippet["description"] as? String ?? ""
let video = Video(videoId: videoId, description: description)
self.videos.append(video)
}
}
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
} catch {
print(error)
}
}
}
task.resume()
}
In cellForRow assign the values to the text properties
let video = videos[indexPath.row]
cell.textLabel!.text = video.videoId
cell.detailTextLabel?.text = video.description