How can I insert this entry into my dictionary? - swift

Question

I have a swift class called ArticleArchive as follows
import Foundation
class ArticleArchive: NSObject, NSCoding {
var entries: Dictionary<String, Dictionary<String, String>>?
var userDefaultsKey = "savedArticles"
override init() {
self.entries = Dictionary<String, Dictionary<String, String>>()
}
init(articles: Dictionary<String, Dictionary<String, String>>) {
self.entries = articles
}
required init(coder aDecoder: NSCoder) {
self.entries = aDecoder.decodeObjectForKey(userDefaultsKey) as? Dictionary
}
func encodeWithCoder(aCoder: NSCoder) {
if let articles = self.entries {
aCoder.encodeObject(articles, forKey: userDefaultsKey)
}
}
func populateArticles(articles: Dictionary<String, Dictionary<String, String>>) {
self.entries = articles
}
func save() {
let data = NSKeyedArchiver.archivedDataWithRootObject(self)
NSUserDefaults.standardUserDefaults().setObject(data, forKey: userDefaultsKey)
}
func clear() {
NSUserDefaults.standardUserDefaults().removeObjectForKey(userDefaultsKey)
}
class func loadSaved() -> ArticleArchive? {
if let data = NSUserDefaults.standardUserDefaults().objectForKey("savedArticles") as? NSData {
return NSKeyedUnarchiver.unarchiveObjectWithData(data) as? ArticleArchive
}
return nil
}
}
In a viewController, I have the following var of type ArticleArchive at the top of the class
var savedArticles : ArticleArchive? = nil
In viewDidLoad I do the following to initialise the variable
if let savedArticles:ArticleArchive = ArticleArchive.loadSaved() {
self.savedArticles = savedArticles
} else {
self.savedArticles = ArticleArchive()
}
I am trying to insert a Dictionary<String, String> into the savedArticles variable like so but it doesn't work.
let currentDictionary = filtered[indexPath.row] as Dictionary<String, String>
self.savedArticles?.entries[currentDictionary["link"]] = currentDictionary
I get an error that states "Could not find an overload for 'subscript' that accepts the supplied arguments"
I've gone around in circles trying different things but no luck, maybe someone can help me out. How can I insert currentDictionary (a Dictionary<String, String>) into savedArticles?

Answer 1

The insertion works, if the dictionary entries is non-optional
There is a good reason to use non-optional types.
Let's assume that when the object ArticleArchive exists, there exists also the entries dictionary which is empty by default.
The encodeWithCoder and init(coder) methods are also safe, because it's ensured that the non-optional entries dictionary is saved anyway even if it's empty, so it's never nil.
Here's the code
Edit : I added a type alias ArticleDictionary for better readability
class ArticleArchive: NSObject, NSCoding {
typealias ArticleDictionary = Dictionary<String, Dictionary<String, String>>
var entries: ArticleDictionary
var userDefaultsKey = "savedArticles"
override init() {
self.entries = ArticleDictionary()
}
init(articles: ArticleDictionary) {
self.entries = articles
}
required init(coder aDecoder: NSCoder) {
self.entries = aDecoder.decodeObjectForKey(userDefaultsKey) as! ArticleDictionary
}
func encodeWithCoder(aCoder: NSCoder) {
aCoder.encodeObject(self.entries, forKey: userDefaultsKey)
}
func populateArticles(articles: ArticleDictionary) {
self.entries = articles
}
func save() {
let data = NSKeyedArchiver.archivedDataWithRootObject(self)
NSUserDefaults.standardUserDefaults().setObject(data, forKey: userDefaultsKey)
}
func clear() {
NSUserDefaults.standardUserDefaults().removeObjectForKey(userDefaultsKey)
}
class func loadSaved() -> ArticleArchive? {
if let data = NSUserDefaults.standardUserDefaults().objectForKey("savedArticles") as? NSData {
return NSKeyedUnarchiver.unarchiveObjectWithData(data) as? ArticleArchive
}
return nil
}
}
as the link key might not exist, the value must be unwrapped.
savedArticles.entries[currentDictionary["link"]!] = currentDictionary

Answer 2

I modified your class to have this method:
func addEntry(key:String, dict:Dictionary<String,String>){
self.entries![key] = dict;
}
Then you can do this:
self.savedArticles?.addEntry(currentDictionary["link"]!, dict: currentDictionary)
Seems to work.
EDIT : If for some reason entries has to remain optional, then this can prevent a runtime crash (bit hacky but works)
func addEntry(key:String, dict:Dictionary<String,String>){
if let e = self.entries{
self.entries![key] = dict;
}else{
print("avoided runtime crash!")
}
}