Error subscript - arrays

Question

I got that error a while ago and I'm not sure, what's wrong. The Post is just normal custom class with two attributes of type String and int.
web api :http://jsonplaceholder.typicode.com/posts
PostService :
class PostService {
var settings:Settings!
init(){
self.settings = Settings()
}
func getPosts(callback:(NSArray) ->()){
request(settings.viewPost, callback: callback)
}
func request(url:String , callback:(NSArray) ->() ){
let nsURL = NSURL(string: url)
let task = NSURLSession.sharedSession().dataTaskWithURL(nsURL!){(data , repsonse , error) in
//var error:NSError?
do {
let response = try NSJSONSerialization.JSONObjectWithData(data!, options:NSJSONReadingOptions.MutableContainers) as! NSArray
callback(response)
} catch {
print(error)
}
}
task.resume()
}
}
settings :
import Foundation
class Settings {
var viewPost = "http://jsonplaceholder.typicode.com/posts"
}
post:
class Post {
var _userId:Int
var _title: String
init(userid:Int , title:String){
self._userId = userid
self._title = title
}
func toJSON() ->String{
return ""
}
}
and tableViewController:
class TableViewController: UITableViewController {
var postsCollection = [Post]()
var service:PostService!
override func viewDidLoad() {
super.viewDidLoad()
service = PostService()
service.getPosts{
(response) in
self.loadPosts(response[" "] as! NSArray )
}
}
func loadPosts(posts:NSArray){
for post in posts{
var userId = post["userId"] as! Int
var title = post["title"] as! String
let postObj = Post(userid: userId, title: title)
postsCollection.append(postObj)
dispatch_async(dispatch_get_main_queue()){
self.tableView.reloadData()
}
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 0
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return postsCollection.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)
let post = postsCollection[indexPath.row] as NSData
cell.textLabel?.text = post._userId
cell.detailTextLabel = post._title
return cell
}
why error Cannot subscript a value of type '[Post]' in line

Answer 1

I'm not sure that this is the issue but it is an issue.
Since postsCollection has a distinct type there is no need to cast the type.
NSData is the wrong type anyway.
let post = postsCollection[indexPath.row] // the compiler infers to Post
Side note: Put the dispatch block to reload the table view after the repeat loop to create the Post instances. Reloading the table view in each iteration of the loop is very expensive and not necessary.
for post in posts {
...
}
dispatch_async(dispatch_get_main_queue()){
self.tableView.reloadData()
}
And (public) properties starting with a underscore are pretty unusual (in Swift).
PS: There are two further issues
cell.textLabel?.text = String(post._userId)
cell.detailTextLabel?.text = post._title
Edit: Simple working solution, there are only two classes
class Post
class Post : CustomStringConvertible {
var userId:Int
var title: String
init(userid:Int , title:String){
self.userId = userid
self.title = title
}
var description : String { return String(userId) }
}
class TableViewController
class TableViewController: UITableViewController {
var postsCollection = [Post]()
override func viewDidLoad() {
super.viewDidLoad()
let url = NSURL(string: "http://jsonplaceholder.typicode.com/posts")
NSURLSession.sharedSession().dataTaskWithURL(url!){ [unowned self] (data , repsonse , error) in
if error != nil {
print(error!)
} else {
do {
let posts = try NSJSONSerialization.JSONObjectWithData(data!, options:NSJSONReadingOptions.MutableContainers) as! [[String:AnyObject]]
for post in posts {
let postObj = Post(userid: post["userId"] as! Int, title: post["title"] as! String)
self.postsCollection.append(postObj)
}
dispatch_async(dispatch_get_main_queue()){
self.tableView.reloadData()
}
} catch let error as NSError {
print(error)
}
}
}.resume()
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int { return 1 }
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int { return postsCollection.count }
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)
let post = postsCollection[indexPath.row]
cell.textLabel!.text = String(post.userId)
cell.detailTextLabel!.text = post.title
return cell
}
}