- Save dictionary array in user defaults swift archive#
- Save dictionary array in user defaults swift code#
If your Dictionary is really very long, there may be a better way to persist it. (By the way, generally, UserDefaults is not designed to contain very long objects.
Save dictionary array in user defaults swift code#
You are not showing enough code to show how. What is going on here and how can I fix it? Using Codable can be one possible way to do it. Strongly typed: You declare the type and default value upfront. Its used in production by all my apps (1 million+ users). It uses UserDefaults underneath but exposes a type-safe facade with lots of nice conveniences. Your custom type `Place` does not seem to be any of them, so you cannot store the `Dictionary` into UserDefaults.Īs noted in the doc, you need to create an instance of Data. Store key-value pairs persistently across launches of your app. In Swift, Data, String, number types and Bool, Date, Array, or Dictionary are bridged to those types, just that (or for collections, a combination of instances of) means all the elements, keys and values needs to to be any of them when Array or Dictionary.
Save dictionary array in user defaults swift archive#
If you want to store any other type of object, you should typically archive it to create an instance of NSData.
Even if you would want to load up the Double value for the volume (i.e 4.5), which is a very small piece of data, your iPhone would have to load up the entire plist before accessing such volume data.UserDefaults can only store plist objects.Ī default object must be a property list-that is, an instance of (or for collections, a combination of instances of) NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary. So, all of it gets loaded up before you can access any of the values contained inside the keys.Įx. → User Defaults is not a database and it should not be used as a DB.īecause the key-value pairs of User Defaults are saved into a "plist", and that entire plist of your UserDefault has to be loaded up synchronously. → Once you try to store arrays or any big types of data, it can easily become unmanageable. You should only really be using UserDefaults to persist small bits of data. As mentioned, you can use UserDefaults to store arrays and dictionaries, like this: let array Apple, Banana t(array, forKey: Fruits). Your app would crash if the String is wrong Just call arrayObject on the JSON object: (json. It's a good idea to keep a Constants.swift file to store the key strings You cannot save SwiftyJSON's custom type JSON to UserDefaults but you can save the raw array because a deserialized JSON collection type is property list compliant. Apart from that a dictionary retrieved from UserDefaults is String:Any by default, you have to conditional downcast the object. set (dictionary, "forKey: "dict" ) let myDict = defaults. You save a dictionary but retrieve an array. Find the student with the highest gpa and display first name and the last. array (forKey : "array" ) as ! // You would have to typecast it as Swift does not know what the data // type is by default let dictionary = ĭefaults. Each dictionary in the array represents a student with first name, last name, and gpa. object (forKey : "AppLastOpenedByUser" ) let myArray = defaults. float (forKey : " Volume ) let appLastOpened = defaults. set (array, forKey : "array" ) let volume = defaults. set ( Date ( ), forKey : "AppLastOpenedByUser" ) let array = ĭefaults. let array 'horse', 'cow', 'camel', 'sheep', 'goat' let defaults UserDefaults. set ( "Angela", forKey : "Name" )ĭefaults. This can support saving data types like Bool, Dictionary, Int, String, Data, and Array.
set ( true, forKey : "MusicOn" )ĭefaults. UserDefault can save integers, booleans, strings, arrays, dictionaries, dates and more, but you should be careful not to save too much data because it will slow the launch of your app. set ( 0.24, forKey : "Volume" )ĭefaults.
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