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iOS Notes 29: How to save Dictionary in UserDefaults?

Updated: April 16, 2020

Using a dictionary is awesome and very easy but it is hard to save in UserDefaults. Definitely Apple should rework on it.

Code:

func saveDictionary(dict: Dictionary<Int, String>, key: String){
     let preferences = UserDefaults.standard
     let encodedData: Data = NSKeyedArchiver.archivedData(withRootObject: dict)
     preferences.set(encodedData, forKey: key)
     // Checking the preference is saved or not
     didSave(preferences: preferences)
}
    
func getDictionary(key: String) -> Dictionary<Int, String> {
     let preferences = UserDefaults.standard
     if preferences.object(forKey: key) != nil{
     let decoded = preferences.object(forKey: key)  as! Data
     let decodedDict = NSKeyedUnarchiver.unarchiveObject(with: decoded) as! Dictionary<Int, String>
            
     return decodedDict
   } else {
      let emptyDict = Dictionary<Int, String>()
      return emptyDict
   }
}

Gist:

We simply convert our dictionary to Data object via NSKeyedArchiever and decode our data via NSKeyedUnachiever. If you’re a newbie on iOS, this might look confusing but just try to use it and trace it. You will figure it out your own and you will never forget that :)

Extra Info 1: You can use your own Custom Models to save in your UserDefaults via this method.

Extra Info 2: You can save Arrays via this method.

If you have any question, ask me :)