Swift 4 We need to serialize our swift object to save it into userDefaults. In swift 4 we can use Codable protocol, which makes our life easy on serialization and JSON parsing Workflow(Save swift object in UserDefaults): Confirm Codable protocol to model class(class Place : Codable). Create object of class. Serialize that class using JsonEncoder … Read more
As long as there’s enough space on the iPhone/iPad, you can store NSUserDefault values. All those values is stored into a .plist file, and this file is very small, most of the time under 1 kb (unless you store a lot of data).
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 … Read more
You can remove the application’s persistent domain like this: NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier]; [[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain]; In Swift 3 and later: if let bundleID = Bundle.main.bundleIdentifier { UserDefaults.standard.removePersistentDomain(forName: bundleID) } This is similar to the answer by @samvermette but is a little bit cleaner IMO.
The question reads “array of array” but I think most people probably come here just wanting to know how to save an array to UserDefaults. For those people I will add a few common examples. String array Save array let array = [“horse”, “cow”, “camel”, “sheep”, “goat”] let defaults = UserDefaults.standard defaults.set(array, forKey: “SavedStringArray”) Retrieve … Read more
You need to convert it to NSData using NSKeyedArchiver before storing it to NSUserDefaults, try like this: update: Xcode 11.4 • Swift 5.2 or later import UIKit class ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() let list = List(name: “Student”) list.answers = [Answer(english: “english answer”, chinese: “中文回答”)] let data = (try? NSKeyedArchiver.archivedData(withRootObject: [list], requiringSecureCoding: … Read more
There seems to be so much confusion about user defaults. Think of it this way. It’s essentially the same as you having a global dictionary available throughout your app. If you add/edit/remove a key/value to the global dictionary, that change is immediately visible anywhere in your code. Since this dictionary is in memory, all would … Read more
In Swift 4 this is pretty much trivial. Make your struct codable simply by marking it as adopting the Codable protocol: struct Song:Codable { var title: String var artist: String } Now let’s start with some data: var songs: [Song] = [ Song(title: “Title 1”, artist: “Artist 1”), Song(title: “Title 2”, artist: “Artist 2”), Song(title: … Read more
You can print all current NSUserDefaults to the log: Just keys: NSLog(@”%@”, [[[NSUserDefaults standardUserDefaults] dictionaryRepresentation] allKeys]); Keys and values: NSLog(@”%@”, [[NSUserDefaults standardUserDefaults] dictionaryRepresentation]);
I found out one alternative, before save, I encode the root object (NSArray object) using NSKeyedArchiver, which ends with NSData. Then use UserDefaults save the NSData. When I need the data, I read out the NSData, and use NSKeyedUnarchiver to convert NSData back to the object. It is a little cumbersome, because i need to … Read more