There are two areas of my ViewController that are showing this warning.
geoCoder.reverseGeocodeLocation(location, completionHandler: { (data, error) -> Void in
guard let placeMarks = data as? [CLPlacemark] else { // warning
return
}
let loc: CLPlacemark = placeMarks[0]
let addressDict : [NSString: NSObject] = loc.addressDictionary as! [NSString: NSObject]
let addrList = addressDict["FormattedAddressLines"] as! [String]
~ and ~
func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
print("Returning Custom label")
var label = view as! UILabel!// warning
if label == nil {
label = UILabel()
}
label?.font = UIFont(name: "Avenir", size: 18)!
....
How can I fix these?
According to the SE-0054 proposal, which has been implemented as of Swift 4.2, the use of implicitly unwrapped optional values is restricted to:
property and variable declarations
initializer declarations
function and method declarations
subscript declarations
parameter declarations
(with the exception of vararg parameters)
And downcasting with as! is not one of them
Related
I am able to parse JSON and adding cells in Collectionview.. but if i move from this Viewcontroller and coming to viewcontroller then collectionview is not showing.. but added data in JSON
code for adding collectionview and JSON parsing:
class ImageItemModel{
var title: String?
var profileImage: UIImage?
var pic_id: Double?
init(title: String?, imgTitle: UIImage?, pic_id: Double?) {
self.title = title
self.profileImage = imgTitle
self.pic_id = pic_id
}
}
class EditProfileImageViewController: UIViewController {
#IBOutlet weak var titleTextfield: UITextField!
private var imageProfile : UIImage?
private var imagePicker : EasyImagePicker?
#IBOutlet weak var collectionView: UICollectionView!
var arrImageItems = [ImageItemModel]()
#IBAction func imgtitleSaveBtn(_ sender: Any) {
postServiceCall()
}
fileprivate func postServiceCall(){
if titleTextfield.text?.trim() == ""{
return self.view.makeToast("please add service title")
}
let parameters = ["image_title" : titleTextfield.text?.trim() ?? ""]
APIReqeustManager.sharedInstance.uploadMultipartFormData(param: parameters, url: CommonUrl.edit_profile_images, image: imageProfile, fileName: "image", vc: self, isHeaderNeeded: true) {(responseData) in
print("edit profile result \(responseData)")
if let result = responseData.dict?["result"] as? NSDictionary{
let success = result["status"] as? [String : Any]
let message = success?["message"] as? String
if message == "Success"{
let image = result["image"] as? [String : Any]
let picId = image?["id"]
self.arrImageItems.append(ImageItemModel(title: self.titleTextfield.text, imgTitle: self.imageProfile, pic_id: picId as! Double))
self.collectionView.reloadData()
}
else{
self.view.makeToast(CommonMessages.somethingWentWrong)
}
}
}
}
extension EditProfileImageViewController : UICollectionViewDelegate,UICollectionViewDataSource{
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return arrImageItems.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ImageCollectionViewCell", for: indexPath) as! ImageCollectionViewCell
cell.imgView.image = arrImageItems[indexPath.item].profileImage
cell.lblTitle.text = arrImageItems[indexPath.row].title
cell.deleteButton.tag = indexPath.row
cell.deleteButton.addTarget(self, action: #selector(deleteService(sender:)), for: UIControl.Event.touchUpInside)
return cell
}
}
with the above code i am able to add collectionview cells and able to store data in JSON but.. if i move from this viewcontroller and coming back to this viewcontroller then collectionview is not showing, why? whats wrong? please do help me with code.. i got stuck here from long time.
There are couple of issues that you should fix for this to work properly. I will give you reason for each.-
You are loading your data with the postServiceCall() method which has an asynchronous network call. There is no way to know when the controller is done fetching the data to the arrImageItems array. So, you should have used a completion handler.
Now you are updating the collectionView within the asynchronous dataTask which a background thread. BIG mistake. Whenever you have any UI related task, you do it under the main thread. So, you could refactor the APIReqeustManager.sharedInstance.uploadMultipartFormData() part of your code following way-
APIReqeustManager.sharedInstance.uploadMultipartFormData(param: parameters, url: CommonUrl.edit_profile_images, image: imageProfile, fileName: "image", vc: self, isHeaderNeeded: true) {(responseData) in
print("edit profile result \(responseData)")
if let result = responseData.dict?["result"] as? NSDictionary{
let success = result["status"] as? [String : Any]
let message = success?["message"] as? String
if message == "Success"{
let image = result["image"] as? [String : Any]
let picId = image?["id"]
self.arrImageItems.append(ImageItemModel(title: self.titleTextfield.text, imgTitle: self.imageProfile, pic_id: picId as! Double))
DispatchQueue.main.async {
self.collectionView.reloadData()
}
}
else{
DispatchQueue.main.async {
self.view.makeToast(CommonMessages.somethingWentWrong)
}
}
}
}
Now unless you want your viewcontroller to show the data in your collectionView only when the action, imgtitleSaveBtn(_:) is triggered, you need to get data everytime, when your view controller appeared on screen. To fix that issue, you should get the data in the viewWillAppear(_:) method like-
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
postServiceCall()
}
Now, the above two edits should fix your issue depending on how you want to load your collectionview but your code is breaking quite some coding standards. Coding standards sounds like a clique but trust me you want to follow those if you ever want to update the capability of your app without breaking it. The following is just some hints-
Whenever you are in an asynchronous call, you should consider calling a completion handler for returning your data.
Should look into your methods, you are dangerously breaking the single responsibility principal.
In more than one place, you force unwrapped. Bad idea. You need your system to have a fail safe rather than just crashing on you.
Update 2:
Updates with a design pattern:
Compartmentalise your code in MVC pattern. Put the ImageItemModel class in its own file. See the image below to understand the design-
Customize the collectionViewCell within the ImageCollectionViewCell. Let's assume your custom cell has only the outlets.
class ImageCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var imgView: UIImageView!
#IBOutlet weak var lblTitle: UILabel!
#IBOutlet weak var deleteButton: UIButton!{
didSet{
deleteButton.addTarget(self, action: #selector(deleteService(_:)), for: .touchUpInside)
}
}
// however this could easily be done with IBAction
#objc func deleteService(_ sender: UIButton){
}
}
Update the postServiceCall and return the data to your controller with a completion handler, means when the postServiceCall is done executing, an array of images or an empty array should be returned based on success or failure. Then the controller can decide what to do with the data, in your case update UI. with couple of refactoring, here is the updated controller code.
import UIKit
import EasyImagePicker
class EditProfileImageViewController: UIViewController {
#IBOutlet weak var collectionView: UICollectionView!{ //for troubleshooting
didSet{ //purpose, do it from code
collectionView.delegate = self
collectionView.dataSource = self
}
}
#IBOutlet weak var titleTextfield: UITextField!
private var imageProfile : UIImage?
private var imagePicker : EasyImagePicker? // you never used this var.
var arrImageItems = [ImageItemModel]()
// any time a view controller appears on screen this method gets called.
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
reloadMyCollectionView()
}
#IBAction func imgtitleSaveBtn(_ sender: Any) {
reloadMyCollectionView()
}
fileprivate func reloadMyCollectionView(){
postServiceCall{ images in
self.arrImageItems = images
DispatchQueue.main.async {
self.collectionView.reloadData()
}
}
}
// look into escaping closures to understand, why you need it here
fileprivate func postServiceCall(completed: #escaping(_ images: [ImageItemModel])->Void){
// don't force unwrap, get optional values safely with guard let
guard let titleText = titleTextfield.text, titleText == "" else{
return
}
let parameters = ["image_title" : titleText]
APIReqeustManager.sharedInstance.uploadMultipartFormData(param: parameters, url: CommonUrl.edit_profile_images, image: imageProfile, fileName: "image", vc: self, isHeaderNeeded: true) {(responseData) in
print("edit profile result \(responseData)")
//capture the data in local scope and return that array with a completion handler
var imageItems = []
if let result = responseData.dict?["result"] as? NSDictionary{
let success = result["status"] as? [String : Any]
let message = success?["message"] as? String
if message == "Success"{
let image = result["image"] as? [String : Any]
let picId = image?["id"]
imageItems.append(ImageItemModel(title: self.titleTextfield.text, imgTitle: self.imageProfile, pic_id: picId as! Double))
}
}
self.completed(imageItems) // if there is nothing in result,
//imageItems will be empty, otherwise it will have imageItemModel data
}
}
}
extension EditProfileImageViewController : UICollectionViewDelegate,UICollectionViewDataSource{
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return arrImageItems.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ImageCollectionViewCell", for: indexPath) as? ImageCollectionViewCell{
cell.imgView.image = arrImageItems[indexPath.item].profileImage
cell.lblTitle.text = arrImageItems[indexPath.row].title
cell.deleteButton.tag = indexPath.row
//cell.deleteButton.addTarget(self, action: #selector(deleteService(sender:)), for: UIControl.Event.touchUpInside)
return cell
}
else{
return UICollectionViewCell()
}
}
}
Notice postServiceCall and cellForItemAt methods.
If you still have the same issue then you need to show your whole code to get any further help.
The code in my viewcontroller-class is executed before the JSON-download-process is ready even though there is a completion handler in the func for downloading JSON an a DispatchGroup(). I store the JSON-data in an array called "fetchedModules" and this is filled with 11 items in this case. Why does this happen?
result in console:
---> in Class PostCell - func numberOfSections: 0
JSON call finished
// ViewController
override func viewDidLoad() {
super.viewDidLoad()
let group = DispatchGroup()
group.enter()
self.fetchJSON()
// here calling downloadJSONasync
group.leave()
group.notify(queue: .main) {
print("JSON call finished")
}
...
// networkService with completion
func downloadJSONasync(searchItem: String, completion: #escaping ([NSDictionary]) -> Void) {
//request.cachePolicy = URLRequest.CachePolicy.reloadIgnoringLocalCacheData
request.httpMethod = "GET"
let configuration = URLSessionConfiguration.default
//let session = URLSession(configuration: configuration, delegate: nil)
let session = URLSession(configuration: configuration)
let task = session.dataTask(with: request, completionHandler: {(data, response, error) in
guard let data = data, error == nil else { return }
if (error != nil) {
print("error!")
}
else{
do {
let fetchedData = try JSONSerialization.jsonObject(with: data, options: JSONSerialization.ReadingOptions.allowFragments) as! [NSDictionary]
completion(fetchedData)
}
catch {
print("error")
}
}
})
task.resume()
}
// call in viewController
override func numberOfSections(in tableView: UITableView) -> Int {
print("---> in Class PostCell - func numberOfSections: \(String(describing: fetchedModules.count))")
return fetchedModules.count
// code of fetchJSON
func fetchJSON()
{
let baseurl = AppConstants.Domains.baseurl // https://m.myapp2go.de
let compositURL = baseurl + "getmodules_noItems.php?id=\(AppConstants.appString.startString)"
let encodedUrl : String! = compositURL.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed) // remove the spaces in the url string for safty reason
let JSONurl = URL(string: encodedUrl)! // convert the string into url
var JSONrequest = URLRequest(url: JSONurl) // make request
JSONrequest.httpMethod = "GET"
//JSONrequest.cachePolicy = .reloadIgnoringCacheData
let networkService = NetworkService(request: JSONrequest)
networkService.downloadJSONasync(searchItem: AppConstants.appString.startString, completion: { (fetchedData) in
fetchedModules.removeAll()
DispatchQueue.main.async {
for eachFetchedModul in fetchedData {
let eachModul = eachFetchedModul
if
let custid = eachModul["custid"] as? String,
let modulcat = eachModul["modulcat"] as? String,
let modulname = eachModul["modulname"] as? String,
let comment = eachModul["comment"] as? String
{
fetchedModules.append(CModules(custid: custid, modulcat: modulcat, modulname: modulname, comment: comment))
print(custid)
print(modulcat)
print(modulname)
print(comment)
print("---------------------")
}
}// for end
// ... somehow set data source array for your table view
self.tableView.reloadData()
}// dispatch
}
)} // func end
Because fetchJSON returns immediately, before the JSON is downloaded. The effect is that the DispatchGroup is entereed and left right away, without waiting for the JSON:
group.enter()
self.fetchJSON() // returns immediately
group.leave() // the JSON has yet to be downloaded
To wait until the JSON has arrived, add a completion handler to fetchJSON:
override func viewDidLoad() {
group.enter()
self.fetchJSON {
group.notify(queue: .main) {
print("JSON call finished")
}
group.leave()
}
}
// Change the data type of the completion handler accordingly
func fetchJSON(completionHandler: #escaping (Data?) -> Void) {
// ...
networkService.downloadJSONasync(searchItem: AppConstants.appString.startString) { fetchedData in
defer { completionHandler(fetchedData) }
// ...
}
)
Using defer ensures that the completion handler will always be called, no matter how the outer closure returns. I'm not clear why you use a DispatchGroup here as there is no waiting, but I kept it in place to answer your question.
Your table view doesn't have any data from the beginning because any data hasn't been fetched yet. So it's ok, that table view has no cells. You just need to reloadData of your table view since now you appended elements to table view's data source array and now you should show this data.
Please, don't use DispatchGroup for this, just use your completion parameter of your method and inside of the completion closure after data are received set data source array for table view and then ... reload data of table view
downloadJSONasync(searchItem: "someString") { dictionary in
DispatchQueue.main.async { // don't forget that your code doesn't run on the main thread
// ... somehow set data source array for your table view
self.tableView.reloadData()
}
}
Note that you should avoid using NSDictonary and you should rather use Dictionary. Also from Swift 4+ you can use Codable instead of JSONSerialization.
Edit: Please ignore the old answers. I can't create a new question my accunt was blocked. So I edited this one with a new question in the title.
How can i have my data result as soon as i viewDidLoad my tableView ?
Here is a snippet of my code. Can anyone help me to understand the asynchronous part that make my code fetch data and bring me back the result late.
`
let apiUrl = "https://shopicruit.myshopify.com/admin/products.json?
page=1&access_token=c32313df0d0ef512ca64d5b336a0d7c6"
var myRowProduct : String = ""
var productArrayName : [String] = []
var productsPassedOver : [String] = []
override func viewDidLoad() {
super.viewDidLoad()
getFullProductsJson(url: apiUrl, tag1: myRowProduct){array, err in
if err != nil {
print("ERROR 2")
}else{
self.productsPassedOver = array
self.tableView.reloadData()
print("productsPassedOver \(self.productsPassedOver)")
}
}
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return productsPassedOver.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "ProductCell", for: indexPath)
cell.selectionStyle = .none
cell.textLabel?.text = "\(indexPath.row + 1). " + productsPassedOver[indexPath.row] + "\n" //label are in every single cell. The current text that is displayed by the label
cell.textLabel?.numberOfLines = 0; //removes any limitations on the number of lines displayed
return cell
}
//Networking JSON
func getFullProductsJson(url: String, tag1: String, completion: #escaping ([String], Error?) -> ()) {
Alamofire.request(url, method: .get).responseJSON {
response in
//response.result.value comes back as an optional so use ! to use it. Also value have datatype of Any? thats why we JSON casting
if response.result.isSuccess{
let fullJSON : JSON = JSON(response.result.value!)
let finalArrayOfProductS = self.updateTagProductData(json: fullJSON, tag2: tag1)
completion(finalArrayOfProductS, nil)
}
else{
print("Error JSON")
}
}
}
//JSON parsing, deal with formatting here
func updateTagProductData(json : JSON, tag2: String) -> [String]{
let tagClicked = tag2
var nbOfProducts : Int = 0
nbOfProducts = json["products"].count
var inventoryAvailableTotal : Int = 0
var nbOfVariants : Int = 0
for i in 0..<nbOfProducts {
let tagsGroup : String = json["products"][i]["tags"].stringValue
let productName : String = json["products"][i]["product_type"].stringValue
nbOfVariants = json["products"][i]["variants"].count
if tagsGroup.contains(tagClicked){
for j in 0..<nbOfVariants{
inventoryAvailableTotal += json["products"][i]["variants"][j]["inventory_quantity"].int!
}
print("\(tagClicked) tag exist in the product \(i): \(productName)")
print("inventorytotal \(inventoryAvailableTotal)")
productArrayName.append("\(productName): \(inventoryAvailableTotal) available")
}
}
return productArrayName
}
}
`
This is a function that does something in the background and return immediately, and when it finishes, it calls your completion handler.
So it is natural for this function to go directly to the return finaleNbOfRowsInProductsListPage.
Your solution is that the function shouldn't return the value, but it should
accept a completion handler, and call it when ended. This is the continuation passing style.
func getFullProductsJson(url: String, tag1: String, completion: #escaping (Int?, Error?) -> ()) {
Alamofire.request(url, method: .get).responseJSON {
response in
...
// When you are done
completion(finaleNbOfRowsInProductsListPage, nil)
}
}
Also please note to try avoiding setting a lot of variables, try to make everything a parameter or a return value from a function, this is easier to debug. For example, try to make the list as a parameter that is passed to the completion handler, not as a member variable of your view controller, make this member variable only for the list that is ready to be displayed.
func getFullProductsJson(url: String, tag1: String, completion: #escaping (Products?, Error?) -> ()) {
Alamofire.request(url, method: .get).responseJSON {
response in
...
// When you are done
completion(products, nil)
}
}
var products: [Product] = []
func refreshData() {
getFullProductsJson(url: "YOUR_URL_HERE", tag1: "TAG") {
// Try to use [weak self], also, read about Automatic Reference Counting
productsNullable, error in
if let products = productsNullable {
// Alamofire calls your callback on a background thread
// So you must return to the main thread first when you want
// to pass the result to any UI component.
DispatchQueue.main.async {
self?.products = products
self?.tableView.reloadData()
}
}
}
}
I'm trying to update an object with JSON data. That data is returned in a completion block after it has been parsed. When I try and return it I get the error:
Cannot call value of non-function type '[JSONObject]'
Here is my function:
static func updateResultsDictionary(urlExtension: String, completion: [JSONObject]){
var jsonDataArray = [JSONObject]()
let nm = NetworkManager.sharedManager
_ = nm.getJSONData(urlExtension: urlExtension, completion: {data in
if let jsonDictionary = nm.parseJSONFromData(data) {
let resultDictionaries = jsonDictionary["result"] as! [[String : Any]]
for resultsDictionary in resultDictionaries {// enumerate through dictionary
let jsonInfo = JSONObject(resultsDictionary: resultsDictionary)
jsonDataArray.append(jsonInfo)
}
}
})
completion(jsonDataArray) //The error happens here
}
EDIT: After changing
completion: [JSONObject]
to
completion: #escaping ([JSONObject]) -> Void
it no longer throws that previous error but now when I use the completion block it throws a new error:
Cannot assign value of type '()' to type '[JSONObject]'
override func viewDidLoad() {
super.viewDidLoad()
self.jsonObjectsArray = JSONObject.updateResultsDictionary(urlExtension: "/cities/basel-switzerland", completion: {JSONObject in
self.practiceTableView.reloadData()
})
}
You've declared the completion parameter to be an array of JSONObject. It seems you mean to declare it as a closure that passes one parameter whose type would be an array of JSONObject.
static func updateResultsDictionary(urlExtension: String, completion: #escaping (_: [JSONObject]) -> Void) {
You also need to change how you call this method:
override func viewDidLoad() {
super.viewDidLoad()
JSONObject.updateResultsDictionary(urlExtension: "/cities/basel-switzerland", completion: { (results) in
self.jsonObjectsArray = results
self.practiceTableView.reloadData()
})
}
And your call to:
completion(jsonDataArray)
needs to be moved to where jsonDataArray is actually being set. It needs to be called at the end of the completion block to the call to getJSONData.
I'm trying to parse out JSON into typed classes for safety/convenience, but it's proving very clunky. I wasn't able to find a library or even a post for Swift (Jastor is as close as I got). Here's a fabricated little snippet to illustrate:
// From NSJSONSerialization or similar and casted to an appropriate toplevel type (e.g. Dictionary).
var parsedJson: Dictionary<String, AnyObject> = [ "int" : 1, "nested" : [ "bool" : true ] ]
class TypedObject {
let stringValueWithDefault: String = ""
let intValueRequired: Int
let nestedBoolBroughtToTopLevel: Bool = false
let combinedIntRequired: Int
init(fromParsedJson json: NSDictionary) {
if let parsedStringValue = json["string"] as? String {
self.stringValueWithDefault = parsedStringValue
}
if let parsedIntValue = json["int"] as? Int {
self.intValueRequired = parsedIntValue
} else {
// Raise an exception...?
}
// Optional-chaining is actually pretty nice for this; it keeps the blocks from nesting absurdly.
if let parsedBool = json["nested"]?["bool"] as? Bool {
self.nestedBoolBroughtToTopLevel = parsedBool
}
if let parsedFirstInt = json["firstInt"] as? Int {
if let parsedSecondInt = json["secondInt"] as? Int {
self.combinedIntRequired = parsedFirstInt * parsedSecondInt
}
}
// Most succinct way to error if we weren't able to construct self.combinedIntRequired?
}
}
TypedObject(fromParsedJson: parsedJson)
There's a number of issues here that I'm hoping to work around:
It's extremely verbose, since I need to wrap every single property in a copy-pasted if-let for safety.
I'm not sure how to communicate errors when required properties are missing (as noted above). Swift seems to prefer (?) using exceptions for show-stopping problems (rather than pedestrian malformed data as here).
I don't know a nice way to deal with properties that exist but are the wrong type (given that the as? casting will fail and simply skip the block, it's not very informative to the user).
If I want to translate a few properties into a single one, I need to nest the let blocks proportional to the number of properties I'm combining. (This is probably more generally a problem with combining multiple optionals into one value safely).
In general, I'm writing imperative parsing logic when I feel like I ought to be able to do something a little more declarative (either with some stated JSON schema or at least inferring the schema from the class definition).
I do this using the Jastor framework:
1) Implement a Protocol that has a single function that returns an NSDictionary response:
protocol APIProtocol {
func didReceiveResponse(results: NSDictionary)
}
2) Create an API class that defines an NSURLConnection object that can be used as a Request URL for iOS's networking API. This class is created to simply return a payload from the itunes.apple.com API.
class API: NSObject {
var data: NSMutableData = NSMutableData()
var delegate: APIProtocol?
func searchItunesFor(searchTerm: String) {
// Clean up the search terms by replacing spaces with +
var itunesSearchTerm = searchTerm.stringByReplacingOccurrencesOfString(" ", withString: "+",
options: NSStringCompareOptions.CaseInsensitiveSearch, range: nil)
var escapedSearchTerm = itunesSearchTerm.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)
var urlPath = "https://itunes.apple.com/search?term=\(escapedSearchTerm)&media=music"
var url: NSURL = NSURL(string: urlPath)
var request: NSURLRequest = NSURLRequest(URL: url)
var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: false)
println("Search iTunes API at URL \(url)")
connection.start()
}
// NSURLConnection Connection failed.
func connection(connection: NSURLConnection!, didFailWithError error: NSError!) {
println("Failed with error:\(error.localizedDescription)")
}
// New request so we need to clear the data object.
func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!) {
self.data = NSMutableData()
}
// Append incoming data.
func connection(connection: NSURLConnection!, didReceiveData data: NSData!) {
self.data.appendData(data)
}
// NSURLConnection delegate function.
func connectionDidFinishLoading(connection: NSURLConnection!) {
// Finished receiving data and convert it to a JSON object.
var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data,
options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
delegate?.didReceiveResponse(jsonResult)
}
}
3) Create a class with associated properties that inherits from Jastor
NSDictionary response:
{
"resultCount" : 50,
"results" : [
{
"collectionExplicitness" : "notExplicit",
"discCount" : 1,
"artworkUrl60" : "http:\/\/a4.mzstatic.com\/us\/r30\/Features\/2a\/b7\/da\/dj.kkirmfzh.60x60-50.jpg",
"collectionCensoredName" : "Changes in Latitudes, Changes in Attitudes (Ultmate Master Disk Gold CD Reissue)"
}
]
}
Music.swift
class Music : Jastor {
var resultCount: NSNumber = 0
}
4) Then in your ViewController be sure to set the delegate to self and then make a call to the API's searchITunesFor() method.
var api: API = API()
override func viewDidLoad() {
api.delegate = self;
api.searchItunesFor("Led Zeppelin")
}
5) Implement the Delegate method for didReceiveResponse(). Jastor extends your class to set a NSDictionary of the results returned from the iTunes API.
// #pragma - API Delegates
func didReceiveResponse(results: NSDictionary) {
let music = Music(dictionary: results)
println(music)
}
Short version: Since init isn't allowed to fail, validation has to happen outside of it. Optionals seem to be the intended tool for flow control in these cases. My solution is to use a factory method that returns an optional of the class, and use option chaining inside it to extract and validate the fields.
Note also that Int and Bool aren't children of AnyObject; data coming from an NSDictionary will have them stored as NSNumbers, which can't be cast directly to Swift types. Thus the calls to .integerValue and .boolValue.
Long version:
// Start with NSDictionary since that's what NSJSONSerialization will give us
var invalidJson: NSDictionary = [ "int" : 1, "nested" : [ "bool" : true ] ]
var validJson: NSDictionary = [
"int" : 1,
"nested" : [ "bool" : true ],
"firstInt" : 3,
"secondInt" : 5
]
class TypedObject {
let stringValueWithDefault: String = ""
let intValueRequired: Int
let nestedBoolBroughtToTopLevel: Bool = false
let combinedIntRequired: Int
init(intValue: Int, combinedInt: Int, stringValue: String?, nestedBool: Bool?) {
self.intValueRequired = intValue
self.combinedIntRequired = combinedInt
// Use Optionals for the non-required parameters so
// we know whether to leave the default values in place
if let s = stringValue {
self.stringValueWithDefault = s
}
if let n = nestedBool {
self.nestedBoolBroughtToTopLevel = n
}
}
class func createFromDictionary(json: Dictionary<String, AnyObject>) -> TypedObject? {
// Validate required fields
var intValue: Int
if let x = (json["int"]? as? NSNumber)?.integerValue {
intValue = x
} else {
return nil
}
var combinedInt: Int
let firstInt = (json["firstInt"]? as? NSNumber)?.integerValue
let secondInt = (json["secondInt"]? as? NSNumber)?.integerValue
switch (firstInt, secondInt) {
case (.Some(let first), .Some(let second)):
combinedInt = first * second
default:
return nil
}
// Extract optional fields
// For some reason the compiler didn't like casting from AnyObject to String directly
let stringValue = json["string"]? as? NSString as? String
let nestedBool = (json["nested"]?["bool"]? as? NSNumber)?.boolValue
return TypedObject(intValue: intValue, combinedInt: combinedInt, stringValue: stringValue, nestedBool: nestedBool)
}
class func createFromDictionary(json: NSDictionary) -> TypedObject? {
// Manually doing this cast since it works, and the only thing Apple's docs
// currently say about bridging Cocoa and Dictionaries is "Information forthcoming"
return TypedObject.createFromDictionary(json as Dictionary<String, AnyObject>)
}
}
TypedObject.createFromDictionary(invalidJson) // nil
TypedObject.createFromDictionary(validJson) // it works!
I've also done the following to convert to/from:
class Image {
var _id = String()
var title = String()
var subTitle = String()
var imageId = String()
func toDictionary(dict dictionary: NSDictionary) {
self._id = dictionary["_id"] as String
self.title = dictionary["title"] as String
self.subTitle = dictionary["subTitle"] as String
self.imageId = dictionary["imageId"] as String
}
func safeSet(d: NSMutableDictionary, k: String, v: String) {
if (v != nil) {
d[k] = v
}
}
func toDictionary() -> NSDictionary {
let jsonable = NSMutableDictionary()
self.safeSet(jsonable, k: "title", v: self.title);
self.safeSet(jsonable, k: "subTitle", v: self.subTitle);
self.safeSet(jsonable, k: "imageId", v: self.imageId);
return jsonable
}
}
Then I simply do the following:
// data (from service)
let responseArray = NSJSONSerialization.JSONObjectWithData(data, options: .MutableContainers, error: nil) as NSArray
self.objects = NSMutableArray()
for item: AnyObject in responseArray {
var image = Image()
image.toDictionary(dict: item as NSDictionary)
self.objects.addObject(image)
}
If you want to POST the data:
var image = Image()
image.title = "title"
image.subTitle = "subTitle"
image.imageId = "imageId"
let data = NSJSONSerialization.dataWithJSONObject(image.toDictionary(), options: .PrettyPrinted, error: nil) as NSData
// data (to service)
request.HTTPBody = data;