CODEWITHSUNDEEP
iosswiftnsuserdefaults
user4620095
user4620095

Reputation:

how to save and read dictionary of touples to NSUserDefaults?

I have an dictionary = String: ([(String)], [(Int)], NSDate, Bool, [(String)]) and I attempted to deconstruct it into seperate arrays when then app calls applicationWillTerminate 

    var codes = [(String)]()
    var messages = [[String]]()
    var senders = [[Int]]()
    var dates = [(NSDate)]()
    var bools = [(Bool)]()
    var pairs = [[String]]()

    for code in self.dictionary.keys {

        codes.append(code)
        messages.append(self.dictionary[code]!.0)
        senders.append(self.dictionary[code]!.1)
        dates.append(self.dictionary[code]!.2)
        bools.append(self.dictionary[code]!.3)
        pairs.append(self.dictionary[code]!.4)

    }

    self.userDefaultsMessages.setObject(codes, forKey: "userMessagesArrays")
    self.userDefaultsSenders.setObject(messages, forKey: "userSentArrays")
    self.userDefaultsDates.setObject(senders, forKey: "userDatesArray")
    self.userDefaultsDeletedBool.setObject(dates, forKey: "userDeletedArrays")
    self.userDefaultsPairs.setObject(bools, forKey: "userPairsArrays")
    self.userDefaultsCodeKeys.setObject(pairs, forKey: "userCodesArrays")

    self.userDefaultsCodeKeys.synchronize()
    self.userDefaultsMessages.synchronize()
    self.userDefaultsSenders.synchronize()
    self.userDefaultsDates.synchronize()
    self.userDefaultsDeletedBool.synchronize()
    self.userDefaultsPairs.synchronize()

and then I attempt to pull it all back together when the app calls applicationDidBecomeActive

//read if let savedCodesArray : AnyObject? = self.userDefaultsCodeKeys.objectForKey("userCodesArrays") { self.userCodes = savedCodesArray! as! [String]

        if let savedMessagesArray : AnyObject? = self.userDefaultsCodeKeys.objectForKey("userMessagesArrays") {
            self.Usermessages = savedMessagesArray! as! [[String]]

            if let savedSendersArray : AnyObject? = self.userDefaultsCodeKeys.objectForKey("userSentArrays") {
                self.Usersenders = savedSendersArray! as! [[Int]]

                if let savedDatesArray : AnyObject? = self.userDefaultsCodeKeys.objectForKey("userDatesArray") {
                    self.Userdates = savedDatesArray! as! [NSDate]

                    if let savedBools : AnyObject? = self.userDefaultsCodeKeys.objectForKey("userDeletedArrays") {
                        self.Userbools = savedBools! as! [Bool]

                        if let savedPairs : AnyObject? = self.userDefaultsCodeKeys.objectForKey("userPairsArrays") {
                            self.Userpairs = savedPairs! as! [[String]]
                            var indexPath: Int = 0
                            for code in self.userCodes {
                                self.dictionary[code]! = [self.Usermessages[indexPath], self.Usermessages[indexPath], self.Userdates[indexPath], self.Userbools[indexPath], self.Userpairs[indexPath]]

                            }
                        }
                    }
                }
            }
        }
    }

I am fairly new to iOS development and could use help, how would i save the single dictionary = String: ([(String)], [(Int)], NSDate, Bool, [(String)]) to NSUserDefaults and then later read it.. the documentation was not very helpful since it only worked with simple dictionaries

the code looks incredibly cumbersome so I know I can't be doing it right. It should be a simple solution since I only have one variable to save to NSUserDefaults.

Upvotes: 0

Views: 590

Answers (2)

Duncan C
Duncan C

Reputation: 131418

Short answer: You can't.

NSUserDefaults will only record "property list objects" (dictionaries, arrays, strings, numbers (integer and float), dates, binary data, and Boolean values).

You can't save any other types of data into NSUserDefaults, or into a property list. The only solution is to convert other data types into those types.

Tuples are not one of those types, so they can't be saved into user defaults.

Upvotes: 5

Jon Shier
Jon Shier

Reputation: 12770

First, your interaction with NSUserDefaults is completely wrong. You only need to interact with the shared NSUserDefaults.sharedUserDefaults() instance, not create separate instances, which seems to be what you're doing (i.e. userDefaultsMessages, userDefaultsSenders, etc.).

Second, you don't need to call synchronize() at all. There are very few conditions under which you need to call it manually, and this isn't one of them.

Third, the easiest way to store a particular tuple in NSUserDefaults is to convert it into an Array (or NSArray) and store the result. Of course, this assumes that the tuple contains only types that can be serialized, which your example seems to contain. Unfortunately there's no general solution to this, but creating an array from a tuple is straight forward, as you can just map the tuple indices to array indices.

Finally, such large tuples are usually the result of poor design somewhere along the line. Perhaps refactoring would help resolve your storage issue?

Upvotes: 0

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