Save User model in UserDefaults and append stored Users to array - ios

Question

I have a User model declared like this:
struct User: Codable {
let nickname : String
let fullName: String
let profilePicUrl: URL
}
Then I save the followed user like this
let followedUser = User(nickname: username, fullName: fullName, profilePicUrl: url)
UserDefaults.standard.set(try! PropertyListEncoder().encode(followedUser), forKey: "user")
Next, in the ViewController which should display the followed users count I retrieve the UserDefaults data like this
var followedUsers = [User]()
if let storedObject: Data = UserDefaults.standard.object(forKey: "user") as? Data {
do {
let storedUser: User = try PropertyListDecoder().decode(User.self, from: storedObject)
followedUsers.append(storedUser)
} catch {
print(error)
}
}
Now, my followedUsers array is being updated with the last stored user each time. How can I append my followedUsers array in a proper way?

Answer 1

If you use Codable , then it make sense to use JSONEncoder & JSONDecoder and store the users as an array
do {
// How to save multiple records
var followers = [User]() // Your array of users
let data = try JSONEncoder().encode(followers) //Convert to Data
UserDefaults.standard.set(data, forKey: "data") // Save to User Default
// How to fetch multiple records
// Check If data available in user default
if let da = UserDefaults.standard.data(forKey: "data") {
// Convert Data back to your cod-able struct
let stored = try JSONDecoder().decode([User].self, from: da)
}
}
catch {
print(error)
}
struct User: Codable {
let nickname , fullName: String
let profilePicUrl: URL
}
Don't encourage using userDefault , you can go with CoreData / Realm

Answer 2

As #Sateesh and #Sanjukta said, storing the users in an array and saving that to UserDefaults is one solution.
The reason why your followedUsers array is updated with only one user, is that when you create a new user, you update the same key in UserDefaults each time.
It should be noted that UserDefaults is mainly used to store small amounts of data. Depending on how many User objects you plan to store, UserDefaults might not be the best solution.
The two solutions for data storage that come to mind are Core Data and Realm. Core Data is an Apple framework with which you can storage data on device. You can read more about it here: Core Data
The second option is to use Realm. Realm is is an open source database management system and can be used for on-device data storage too.
If you are interested in the differences between Realm and Core Data, for starters I can recommend this article.
Personally I use Realm in my own projects because I find it easier to implement and faster than Core Data. Please note that this is just my personal preference and others might disagree. Make sure you listen to other opinions and experiment with both before picking sides.
So let's suppose you want to store the User in Realm, you would need to do the following:
Install Realm for your project.
In your podfile add the following: pod 'RealmSwift'.
Run pod install in terminal and use the newly created .xcworkspace from now on.
In Xcode, in AppDelegate import RealmSwift and insert the following code to the didFinishLaunchingWithOptions method:
do {
_ = try Realm()
} catch {
print("Error initialising new Realm \(error)")
}
This initializes a new default Realm, where your User data will be saved.
Create a new User.swift file. In that, import RealmSwift and insert the following:
class User: Object {
#objc dynamic var nickName: String = ""
#objc dynamic var fullName: String = ""
#objc dynamic var profilePicURL: URL?
}
This creates a Realm object, which will contain the data for your users.
Save the followed user like this:
In the view controller where you want to save the user data import RealmSwift, and under the class declaration create a new instance of realm by let realm = try! Realm()
When you have the user data, save to Realm with the following code:
:
let followedUser = User()
do{
try realm.write {
followedUser.nickName = username
followedUser.fullName = fullName
followedUser.profilePicURL = url
realm.add(followedUser)
}
} catch {
print("Error saving to persistent container! \(error)")
}
In the view controller where you need the user data, create an instance of Realm just like before with let realm = try! Realm()
, retrieve users from Realm with the following code: let followedUsers = realm.objects(User.self)
This retrieves all Users from the default realm.
If you need to count the followedUsers you can do so by: followedUsers.count
Hopes this approach helps you to achieve what you wanted in the first place.

Answer 3

Please make the array of object then store the array in userDefaults.
After that you can easily retrive it.
It may help you. Thank you.