Attempt to set a non-property-list object as an NSUserDefaults

Question

I thought I knew what was causing this error  but I can t seem to figure out what I did wrong   Here is the full error message I am getting    Attempt to set a non-property-list object        lt BC Person  0x8f3c140 gt     as an NSUserDefaults value for key personDataArray   I have a Person class that I think is conforming to the NSCoding protocol  where I have both of these methods in my person class   -  void encodeWithCoder  NSCoder   coder        coder encodeObject self personsName forKey   BCPersonsName         coder encodeObject self personsBills forKey   BCPersonsBillsArray       -  id initWithCoder  NSCoder   coder       self    super init       if  self            self personsName    coder decodeObjectForKey   BCPersonsName            self personsBills    coder decodeObjectForKey   BCPersonsBillsArray              return self      At some point in the app  the NSString in the BC PersonClass is set  and I have a DataSave class that I think is handling the encoding the properties in my BC PersonClass  Here is the code I am using from the DataSave class   -  void savePersonArrayData  BC Person   personObject         NSLog   name of the person      personObject personsName         mutableDataArray addObject personObject           set the temp array to the mutableData array     tempMuteArray    NSMutableArray arrayWithArray mutableDataArray           save the person object as nsData     NSData  personEncodedObject    NSKeyedArchiver archivedDataWithRootObject personObject           first add the person object to the mutable array      tempMuteArray addObject personEncodedObject           NSLog   Objects in the array  lu    unsigned long mutableDataArray count           now we set that data array to the mutable array for saving     dataArray     NSArray alloc  initWithArray mutableDataArray         dataArray    NSArray arrayWithArray mutableDataArray           save the object to NS User Defaults     NSUserDefaults  userData    NSUserDefaults standardUserDefaults        userData setObject dataArray forKey   personDataArray         userData synchronize       I hope this is enough code to give you an idea o what I am trying to do   Again I know my problem lie with how I am encoding my properties in my BC Person class  I just can t seem to figure out what though I m doing wrong   Thanks for the help

User · Answer

I ran into this and eventually figured out it was because I was trying to use NSNumber as dictionary keys, and property lists only allow strings as keys. The documentation for setObject:forKey: doesn't mention this limitation, but the About Property Lists page that it links to does:

By convention, each Cocoa and Core Foundation object listed in Table 2-1 is called a property-list object. Conceptually, you can think of “property list” as being an abstract superclass of all these classes. If you receive a property list object from some method or function, you know that it must be an instance of one of these types, but a priori you may not know which type. If a property-list object is a container (that is, an array or dictionary), all objects contained within it must also be property-list objects. If an array or dictionary contains objects that are not property-list objects, then you cannot save and restore the hierarchy of data using the various property-list methods and functions. And although NSDictionary and CFDictionary objects allow their keys to be objects of any type, if the keys are not string objects, the collections are not property-list objects.

(Emphasis mine)

User · Answer

Swift 3 Solution  Simple utility class  class ArchiveUtil        private static let PeopleKey    PeopleKey       private static func archivePeople people    Human   - gt  NSData            return NSKeyedArchiver archivedData withRootObject  people as NSArray  as NSData            static func loadPeople   - gt   Human              if let unarchivedObject   UserDefaults standard object forKey  PeopleKey  as  Data                return NSKeyedUnarchiver unarchiveObject with  unarchivedObject as Data  as   Human                     return nil            static func savePeople people    Human               let archivedObject   archivePeople people  people           UserDefaults standard set archivedObject  forKey  PeopleKey          UserDefaults standard synchronize              Model Class  class Human  NSObject  NSCoding        var name String      var age Int       required init n String  a Int             name   n         age   a             required init coder aDecoder  NSCoder             name   aDecoder decodeObject forKey   name   as  String         age   aDecoder decodeInteger forKey   age               public func encode with aCoder  NSCoder             aCoder encode name  forKey   name           aCoder encode age  forKey   age              How to call  var people    Human     people append Human n   Sazzad   a  21   people append Human n   Hissain   a  22   people append Human n   Khan   a  23    ArchiveUtil savePeople people  people   let others   ArchiveUtil loadPeople    for human in others         print  name     human name    age     human age

User · Answer

To save   NSUserDefaults  currentDefaults    NSUserDefaults standardUserDefaults   NSData  data    NSKeyedArchiver archivedDataWithRootObject yourObject    currentDefaults setObject data forKey   yourKeyName      To Get   NSData  data    currentDefaults objectForKey   yourKeyName    yourObjectType   token    NSKeyedUnarchiver unarchiveObjectWithData data     For Remove   currentDefaults removeObjectForKey   yourKeyName

User · Answer

I had this problem trying save a dictionary to NSUserDefaults  It turns out it wouldn t save because it contained NSNull values  So I just copied the dictionary into a mutable dictionary removed the nulls then saved to NSUserDefaults  NSMutableDictionary  dictionary    NSMutableDictionary dictionaryWithDictionary dictionary trying to save    dictionary removeObjectForKey   NullKey      NSUserDefaults standardUserDefaults  setObject dictionary forKey   key      In this case I knew which keys might be NSNull values

User · Answer

The code you posted tries to save an array of custom objects to NSUserDefaults  You can t do that  Implementing the NSCoding methods doesn t help  You can only store things like NSArray  NSDictionary  NSString  NSData  NSNumber  and NSDate in NSUserDefaults   You need to convert the object to NSData  like you have in some of the code  and store that NSData in NSUserDefaults  You can even store an NSArray of NSData if you need to   When you read back the array you need to unarchive the NSData to get back your BC Person objects   Perhaps you want this   -  void savePersonArrayData  BC Person   personObject        mutableDataArray addObject personObject        NSMutableArray  archiveArray    NSMutableArray arrayWithCapacity mutableDataArray count       for  BC Person  personObject in mutableDataArray             NSData  personEncodedObject    NSKeyedArchiver archivedDataWithRootObject personObject            archiveArray addObject personEncodedObject              NSUserDefaults  userData    NSUserDefaults standardUserDefaults        userData setObject archiveArray forKey   personDataArray

User · Answer

It seems rather wasteful to me to run through the array and encode the objects into NSData yourself  Your error BC Person is a non-property-list object is telling you that the framework doesn t know how to serialize your person object    So all that is needed is to ensure that your person object conforms to NSCoding then you can simply convert your array of custom objects into NSData and store that to defaults  Heres a playground   Edit  Writing to NSUserDefaults is broken on Xcode 7 so the playground will archive to data and back and print an output  The UserDefaults step is included in case its fixed at a later point      Playground - noun  a place where people can play  import Foundation  class Person  NSObject  NSCoding       let surname  String     let firstname  String      required init firstname String  surname String            self firstname   firstname         self surname   surname         super init                MARK  - NSCoding -     required init coder aDecoder  NSCoder            surname   aDecoder decodeObjectForKey  surname   as  String         firstname   aDecoder decodeObjectForKey  firstname   as  String            func encodeWithCoder aCoder  NSCoder            aCoder encodeObject firstname  forKey   firstname           aCoder encodeObject surname  forKey   surname                    Now lets define a function to convert our array to NSData  func archivePeople people  Person   - gt  NSData       let archivedObject   NSKeyedArchiver archivedDataWithRootObject people as NSArray      return archivedObject            Create some people  let people    Person firstname   johnny   surname  appleseed   Person firstname   peter   surname   mill             Archive our people to NSData  let peopleData   archivePeople people   if let unarchivedPeople   NSKeyedUnarchiver unarchiveObjectWithData peopleData  as   Person        for person in unarchivedPeople           print    person firstname   you have been unarchived           else       print  Failed to unarchive people              Lets try use NSUserDefaults let UserDefaultsPeopleKey    peoplekey  func savePeople people  Person         let archivedObject   archivePeople people      let defaults   NSUserDefaults standardUserDefaults       defaults setObject archivedObject  forKey  UserDefaultsPeopleKey      defaults synchronize      func retrievePeople   - gt   Person         if let unarchivedObject   NSUserDefaults standardUserDefaults   objectForKey UserDefaultsPeopleKey  as  NSData           return NSKeyedUnarchiver unarchiveObjectWithData unarchivedObject  as   Person            return nil    if let retrievedPeople   retrievePeople         for person in retrievedPeople           print    person firstname   you have been unarchived           else       print  Writing to UserDefaults is still broken in playgrounds       And Voila  you have stored an array of custom objects into NSUserDefaults

User · Answer

Swift 5  The Codable protocol can be used instead of NSKeyedArchiever    struct User  Codable       let id  String     let mail  String     let fullName  String     The Pref struct is custom wrapper around the UserDefaults standard object   struct Pref       static let keyUser    Pref User      static var user  User            get               if let data   UserDefaults standard object forKey  keyUser  as  Data                   do                       return try JSONDecoder   decode User self  from  data                    catch                       print  Error while decoding user data                                               return nil                   set               if let newValue   newValue                   do                       let data   try JSONEncoder   encode newValue                      UserDefaults standard set data  forKey  keyUser                    catch                       print  Error while encoding user data                                   else                   UserDefaults standard removeObject forKey  keyUser                                    So you can use it this way   Pref user  name    John   if let user   Pref user

User · Answer

Swift with  propertyWrapper  Save Codable object to UserDefault    propertyWrapper     struct UserDefault lt T  Codable gt            let key  String         let defaultValue  T          init   key  String  defaultValue  T                self key   key             self defaultValue   defaultValue                    var wrappedValue  T               get                    if let data   UserDefaults standard object forKey  key  as  Data                      let user   try  JSONDecoder   decode T self  from  data                        return user                                     return  defaultValue                           set                   if let encoded   try  JSONEncoder   encode newValue                        UserDefaults standard set encoded  forKey  key                                                      enum GlobalSettings         UserDefault  user   defaultValue  User name    pass      static var user  User     Example User model confirm Codable  struct User Codable       let name String     let pass String     How to use it    Set value   GlobalSettings user   User name   Ahmed   pass   Ahmed      GetValue print GlobalSettings user

User · Answer

https   developer apple com reference foundation userdefaults 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

User · Answer

Swift- 4 Xcode 9 1  try this code  you can not store mapper in NSUserDefault  you can only store NSData  NSString  NSNumber  NSDate  NSArray  or NSDictionary    let myData   NSKeyedArchiver archivedData withRootObject  myJson  UserDefaults standard set myData  forKey   userJson    let recovedUserJsonData   UserDefaults standard object forKey   userJson   let recovedUserJson   NSKeyedUnarchiver unarchiveObject with  recovedUserJsonData

User · Answer

Swift  5 Very Easy way    MARK - First you need to encoded your arr or what ever object you want to save in UserDefaults   in my case i want to save Picture  NMutableArray  in the User Defaults in   in this array some objects are UIImage  amp  Strings    first i have to encoded the NMutableArray  let encodedData   NSKeyedArchiver archivedData withRootObject  yourArrayName    MARK - Array save in UserDefaults defaults set encodedData  forKey   YourKeyName      MARK - When you want to retreive data from UserDefaults let decoded    defaults object forKey   YourKeyName   as  Data yourArrayName   NSKeyedUnarchiver unarchiveObject with  decoded  as  NSMutableArray    MARK  Enjoy this arrry  yourArrayName

User · Answer

First off  rmaddy s answer  above  is right  implementing NSCoding doesn t help  However  you need to implement NSCoding to use NSKeyedArchiver and all that  so it s just one more step    converting via NSData    Example methods  -  NSUserDefaults    defaults       return  NSUserDefaults standardUserDefaults      -  void  persistObj  id value forKey  NSString   key        self defaults setObject value  forKey key        self defaults synchronize      -  void  persistObjAsData  id encodableObject forKey  NSString   key       NSData  data    NSKeyedArchiver archivedDataWithRootObject encodableObject        self persistObj data forKey key          -  id  objectFromDataWithKey  NSString  key       NSData  data    self defaults objectForKey key       return  NSKeyedUnarchiver unarchiveObjectWithData data       So you can wrap your NSCoding objects in an NSArray or NSDictionary or whatever

[ios] Attempt to set a non-property-list object as an NSUserDefaults

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