Getting error while trying to store Int, arrayof [string] pair in userDefaults

Question

self.fetchMin(forStartDate: start, toEndDate: end) { (min, chal) in

    guard let mins = min, let challenges = chal else {
        return
    }

    let dict: [Int : [String]]  = [mins:challenges]

    UserDefaults.standard.set(dict, forKey: "WeekStates")

}

Hi, In the above program I'm trying to store key and array pair of string in userDefaults but if I do so it crashes unexpectedly.

If I try with one value, its working.

eg:

`let dict: [String]  =  challenges
 UserDefaults.standard.set(dict, forKey: "WeekStates")

libc++abi.dylib: terminating with uncaught exception of type NSException @Anbu.Karthik — Sathish Kumar Gurunathan
– Sathish Kumar Gurunathan, Commented Jun 16, 2017 at 5:03
There will be a "Reason" mentioned in console after "terminating with uncaught exception of type NSException". SHare that please. — Umair Afzal
– Umair Afzal, Commented Jun 16, 2017 at 5:36

Bhavesh Dhaduk · Accepted Answer · 2017-06-16 05:45:48Z

https://developer.apple.com/documentation/foundation/userdefaults

The UserDefaults class provides convenience methods for accessing common types such as floats, doubles, integers, Booleans, and URLs. A default object must be a property list—that is, an instance of (or for collections, a combination of instances of): NSData , NSString , NSNumber , NSDate , NSArray , or NSDictionary . If you want to store any other type of object, you should typically archive it to create an instance of NSData. For more details, see Preferences and Settings Programming Guide.

You can do something like this.

let dict: [Int : [String]]  = [1:["iOS Dev"]]

    UserDefaults.standard.set(NSKeyedArchiver.archivedData(withRootObject: dict as NSDictionary) as NSData, forKey: "4WeekStates")

    if let unarchivedObject = UserDefaults.standard.object(forKey: "4WeekStates") as? Data {

        let dic = NSKeyedUnarchiver.unarchiveObject(with: unarchivedObject as Data) as? NSDictionary
        print(dic!)
    }

Piyush · Accepted Answer · 2017-06-16 05:19:30Z

0

As you mentioned at last point i tried [String] it works.

I'm not sure whether you can store data like type of [Int : [String]], As of my knowledge UserDefaults Property lists can only accept certain types of variables, so it has that limitation. You can store these types of variables:

Array
Data
Date
Dictionary
NSNumber
String

edited Jun 16, 2017 at 5:19

Piyush

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answered Jun 16, 2017 at 5:10

Dharma

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2 Comments

Sathish Kumar Gurunathan Over a year ago

I am saving it has a dictionary only.

Dharma Over a year ago

you cannot store dictionary with a NSNumber or Int as key

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