How to Store Custom Objects in Nsuserdefaults

How to store custom objects in NSUserDefaults

On your Player class, implement the following two methods (substituting calls to encodeObject with something relevant to your own object):

- (void)encodeWithCoder:(NSCoder *)encoder {
//Encode properties, other class variables, etc
[encoder encodeObject:self.question forKey:@"question"];
[encoder encodeObject:self.categoryName forKey:@"category"];
[encoder encodeObject:self.subCategoryName forKey:@"subcategory"];
}

- (id)initWithCoder:(NSCoder *)decoder {
if((self = [super init])) {
//decode properties, other class vars
self.question = [decoder decodeObjectForKey:@"question"];
self.categoryName = [decoder decodeObjectForKey:@"category"];
self.subCategoryName = [decoder decodeObjectForKey:@"subcategory"];
}
return self;
}

Reading and writing from NSUserDefaults:

- (void)saveCustomObject:(MyObject *)object key:(NSString *)key {
NSData *encodedObject = [NSKeyedArchiver archivedDataWithRootObject:object];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:encodedObject forKey:key];
[defaults synchronize];

}

- (MyObject *)loadCustomObjectWithKey:(NSString *)key {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSData *encodedObject = [defaults objectForKey:key];
MyObject *object = [NSKeyedUnarchiver unarchiveObjectWithData:encodedObject];
return object;
}

Code shamelessly borrowed from: saving class in nsuserdefaults

how can store custom objects in NSUserDefaults

First you create custom class Like below.

CustomObject.h

#import <Foundation/Foundation.h>

@interface CustomObject : NSObject<NSCoding>

@property(strong,nonatomic)NSString *name;

@end

CustomObject.m

#import "CustomObject.h"

@implementation CustomObject



- (void)encodeWithCoder:(NSCoder *)encoder {
//Encode properties, other class variables, etc
[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;
}

Then create CustomObject class object and store in NSUserDefaults

Stored your object like this

CustomObject *object =[CustomObject new];
object.name = @"test";

NSMutableArray *arr = [[NSMutableArray alloc]init];
[arr addObject:object];

NSData *encodedObject = [NSKeyedArchiver archivedDataWithRootObject:arr];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:encodedObject forKey:@"storeObject"];
[defaults synchronize];

get custom object from NSUserDefaults like this

 NSData *storedEncodedObject = [defaults objectForKey:@"storeObject"];
NSArray *arrStoreObject = [NSKeyedUnarchiver unarchiveObjectWithData:storedEncodedObject];
for (int i=0; i<arrStoreObject.count; i++)
{
CustomObject *storedObject = [arrStoreObject objectAtIndex:i];
NSLog(@"%@",storedObject.name);

}

Store Custom Objects in NSUserDefaults

You unarchive incorrect object. You store NSArray to NSUserDefaults

NSArray * archiveArray = [userData objectForKey:@"personDataArray"];
for (NSData *personEncodedObject in archiveArray) {
id personObject = [NSKeyedUnarchiver unarchiveObjectWithData:personEncodedObject];
}

How to use NSUserDefaults to store an array of custom classes in Swift?

Your Person class should look like this:

Swift 3:

class Person : NSObject, NSCoding{

// Person dictionary variable
var name: String?
var age: String?
var html_url: String?

init(json: NSDictionary) { // Dictionary object
self.name = json["name"] as? String
self.age = json["age"] as? String
self.html_url = json["html_url"] as? String // Location of the JSON file
}

required init?(coder aDecoder: NSCoder) {

self.name = aDecoder.decodeObjectForKey("name") as? String;
self.age = aDecoder.decodeObjectForKey("age") as? String;
self.html_url = aDecoder.decodeObjectForKey("html") as? String;
}

func encodeWithCoder(aCoder: NSCoder) {
aCoder.encodeObject(self.name, forKey: "name");
aCoder.encodeObject(self.age, forKey: "age");
aCoder.encodeObject(self.html_url, forKey: "html");
}
}

And here you have an example of saving and retrieving the array from NSUserDefaults:

let p = Person()
p.name = "person1"
p.age = "12"
p.html_url = "www.google.ro"

let p2 = Person()
p2.name = "person2"
p2.age = "11"
p2.html_url = "www.google.ro"

let array = [p, p2]

let userDefaults = NSUserDefaults.standardUserDefaults()
userDefaults.setValue(NSKeyedArchiver.archivedDataWithRootObject(array), forKey: "persons")
userDefaults.synchronize()

let array : [Person]
array = NSKeyedUnarchiver.unarchiveObjectWithData(userDefaults.objectForKey("persons") as! NSData) as! [Person]
print("\(array[0].name)\(array[1].name)")

Swift 4:

class Person : NSObject, NSCoding{

// Person dictionary variable
var name: String?
var age: String?
var html_url: String?

init(json: NSDictionary) { // Dictionary object
self.name = json["name"] as? String
self.age = json["age"] as? String
self.html_url = json["html_url"] as? String // Location of the JSON file
}

required init?(coder aDecoder: NSCoder) {
self.name = aDecoder.decodeObject(forKey: "name") as? String;
self.age = aDecoder.decodeObject(forKey: "age") as? String;
self.html_url = aDecoder.decodeObject(forKey: "html") as? String;
}

func encode(with aCoder: NSCoder) {
aCoder.encode(self.name, forKey: "name");
aCoder.encode(self.age, forKey: "age");
aCoder.encode(self.html_url, forKey: "html");
}
}

How to store array list of custom objects to NSUserDefaults?

You need to implement protocol NSCoding for your custom class. Please see this Swift example.

Save custom objects into NSUserDefaults

Actually, you will need to archive the custom object into NSData then save it to user defaults and retrieve it from user defaults and unarchive it again.
You can archive it like this

let teams = [Team(id: 1, name: "team1", shortname: "t1"), Team(id: 2, name: "team2", shortname: "t2")]

var userDefaults = UserDefaults.standard
let encodedData: Data = NSKeyedArchiver.archivedData(withRootObject: teams)
userDefaults.set(encodedData, forKey: "teams")

and unarchive it like this

let decoded  = userDefaults.data(forKey: "teams")
let decodedTeams = NSKeyedUnarchiver.unarchiveObject(with: decoded) as! [Team]

But if you just did that you will get

.Team encodeWithCoder:]: unrecognized selector sent to instance

You will have to make Team conform to NSCoding just like this

class Team: NSObject, NSCoding {
var id: Int
var name: String
var shortname: String


init(id: Int, name: String, shortname: String) {
self.id = id
self.name = name
self.shortname = shortname

}

required convenience init(coder aDecoder: NSCoder) {
let id = aDecoder.decodeInteger(forKey: "id")
let name = aDecoder.decodeObject(forKey: "name") as! String
let shortname = aDecoder.decodeObject(forKey: "shortname") as! String
self.init(id: id, name: name, shortname: shortname)
}

func encode(with aCoder: NSCoder) {
aCoder.encode(id, forKey: "id")
aCoder.encode(name, forKey: "name")
aCoder.encode(shortname, forKey: "shortname")
}
}


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