Storing custom objects in NSUserDefaults - objective-c

Question

I am trying to save an object in NSUserDefaults but i have not been successful in it. Scenario is that, I have an object syncObject of class SyncObjct. I have implemented following methods in SyncObject class
- (NSMutableDictionary*)toDictionary;
+ (SyncObject*)getFromDictionary :(NSMutableDictionary*)dictionary;
- (id) initWithCoder: (NSCoder *)coder;
- (void) encodeWithCoder: (NSCoder *)coder;
And also the SyncObject class is NSCoding class. Now SyncObject class contains an NSMutableArray with name jobsArray. This array contains objects of class JobsObject. I implemented same above methods for this class as well to make it coding compliant. In toDictionary method of SyncObject class, i am storing this array in dictionary by writing following line.
[dictionary setValue:jobsArray forKey:#"jobsArray"];
and I am retrieving it in getFromDictionary method of SyncOject class by writing following line.
+ (SyncObject*)getFromDictionary :(NSMutableDictionary*)dictionary
{
NSLog(#"SyncObject:getFromDictionary");
SyncObject *syncObject = [[SyncObject alloc] init];
#try
{
syncObject.noOfJobs = [[dictionary valueForKey:#"noOfJobs"] intValue];
syncObject.totalJobsPerformed = (TotalJobsPerformed*)[dictionary valueForKey:#"totalobsPerformed"];
syncObject.jobsArray = [dictionary valueForKey:#"jobsArray"];
}
#catch (NSException * e)
{
NSLog(#"EXCEPTION %#: %#", [e name], [e reason]);
}
#finally
{
}
return syncObject;
}
And also I am storing syncObject in NSUserDefault by writing following lines.
NSData *myEncodedObject = [NSKeyedArchiver archivedDataWithRootObject:syncObject];
[userStorage setObject:myEncodedObject forKey:SYNC_OBJECT];
I am retrieving the object from NSUserDefaults by writing following lines
NSData *myEncodedObject = [userStorage objectForKey: SYNC_OBJECT];
syncObject = (SyncObject*)[NSKeyedUnarchiver unarchiveObjectWithData: myEncodedObject];
Problem is that i am not able to retrieve jobsArray correctly. Some invalid object is returned and app crashes when trying to access it. Please can anyone tell me the reason of this problem?
Best Regards

Answer 1

I believe the problem is that NSUserDefaults does not support storing of custom object types.
From Apple's documentation when using -setObject: The value parameter can be only property list objects: NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary. For NSArray and NSDictionary objects, their contents must be property list objects.
You can review the remaining documentation directly from Apple's NSUserDefault Class Reference manual.

Answer 2

Custom class .h
#import <Foundation/Foundation.h>
#interface Person : NSObject
#property(nonatomic, retain) NSArray *names;
#property(strong,nonatomic)NSString *name;
#end
custom class .m
#import "Person.h"
#implementation Person
#synthesize names;
- (void)encodeWithCoder:(NSCoder *)encoder {
[encoder encodeObject:self.name forKey:#"name"];
}
- (id)initWithCoder:(NSCoder *)decoder {
if((self = [super init])) {
//decode properties, other class vars
self.name = [decoder decodeObjectForKey:#"name"];
}
return self;
}
#end
To create Person class object and store and retrieve your stored data from NSUserDefaults
Stored your object :
#import "ViewController.h"
#import "Person.h"
#interface ViewController ()
#property (weak, nonatomic) IBOutlet UITextField *textBox;
#end
NSMutableArray *arr;
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)saveButton:(id)sender {
Person *person =[Person new];
person.name = _textBox.text;
arr = [[NSMutableArray alloc]init];
[arr addObject:person];
NSData *encodedObject = [NSKeyedArchiver archivedDataWithRootObject:arr];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:encodedObject forKey:#"name"];
[defaults synchronize];
}
- (IBAction)showButton:(id)sender {
_label.text = #"";
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSData *storedEncodedObject = [defaults objectForKey:#"name"];
NSArray *arrStoreObject = [NSKeyedUnarchiver unarchiveObjectWithData:storedEncodedObject];
for (int i=0; i<arrStoreObject.count; i++)
{
Person *storedObject = [arrStoreObject objectAtIndex:i];
_label.text = [NSString stringWithFormat:#"%# %#", _label.text , storedObject.name];
}
}
#end