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

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 (
   "<BC_Person: 0x8f3c140>"
) 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!

This question is related to ios objective-c encoding nsuserdefaults

The answer is

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"];

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