UserDefaults and arrays

Question

So not sure what I'm doing wrong here with userDefaults and my array. I'm only seeing the last Int and nothing else added before.

   func addItem(completedTask: Int){
         var array: [Int] = []
         array.append(completedTask)

//   Setting userDefaults
         let userDefaults = UserDefaults.standard
         userDefaults.set(array, forKey: "userDefault-completedItems")
//   Read userDefaults
        let userDefaultArray = userDefaults.array(forKey: "userDefault-completedItems") as? [Int] ?? [Int]()
         print("added items read from userdefaults \(userDefaultArray)")
        for item in userDefaultArray {
              print(item)
         }
  }

SwiftUI

241

Posted by

robevans

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Answer 1

In the first line of addItem(completedTask:), the local variable array is declared and initialized to an empty array ([]).

Whether or not UserDefaults has some value, it is initialized as an empty array.

So, when you call userDefaults.set(array, forKey: "userDefault-completedItems"), array contains only one item: completedTask.

I guess you may want to do something like this:

    private let kUserDefaultsCompletedItems = "userDefault-completedItems"
    
    func addItem(completedTask: Int){
        let userDefaults = UserDefaults.standard
        
        var array: [Int] = userDefaults.array(forKey: kUserDefaultsCompletedItems) as? [Int] ?? []
        array.append(completedTask)
        
        //   Setting userDefaults
        userDefaults.set(array, forKey: kUserDefaultsCompletedItems)
        //   Read userDefaults
        let userDefaultArray = userDefaults.array(forKey: kUserDefaultsCompletedItems) as? [Int] ?? []
        print("added items read from userdefaults \(userDefaultArray)")
    }

Posted by

OOPer

Ah that makes so much sense now. Thank you for the help!

—
robevans

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Answer 2

In the first line of addItem(completedTask:), the local variable array is declared and initialized to an empty array ([]).

Whether or not UserDefaults has some value, it is initialized as an empty array.

So, when you call userDefaults.set(array, forKey: "userDefault-completedItems"), array contains only one item: completedTask.

I guess you may want to do something like this:

    private let kUserDefaultsCompletedItems = "userDefault-completedItems"
    
    func addItem(completedTask: Int){
        let userDefaults = UserDefaults.standard
        
        var array: [Int] = userDefaults.array(forKey: kUserDefaultsCompletedItems) as? [Int] ?? []
        array.append(completedTask)
        
        //   Setting userDefaults
        userDefaults.set(array, forKey: kUserDefaultsCompletedItems)
        //   Read userDefaults
        let userDefaultArray = userDefaults.array(forKey: kUserDefaultsCompletedItems) as? [Int] ?? []
        print("added items read from userdefaults \(userDefaultArray)")
    }

Posted by

OOPer

Ah that makes so much sense now. Thank you for the help!

—
robevans

Add a Comment

UserDefaults and arrays

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