How to store Array in NSUserDefault in Swift?

问题

So I've been trying for a few hours for a way to store an array to NSUserDefault and print them to the cells but the data is not saving as an array, it basically only saves one value at a time.

var emailData = [String]()
    var passwordData = [String]()

@IBAction func addPressed(sender: AnyObject) {

 let defaults = NSUserDefaults.standardUserDefaults()

    emailData.append(addEmail.text!)
    passwordData.append(addPassword.text!)

var storedEmail = defaults.objectForKey("emailData") as? [String] ?? [String]()
var storedPasswords = defaults.objectForKey("passwordData") as? [String] ?? [String]()


// then update whats in the `NSUserDefault`
    defaults.setObject(emailData, forKey: "emailData")
    defaults.setObject(passwordData, forKey: "passwordData")


// call this after you update
defaults.synchronize()        /*

 NSUserDefaults.standardUserDefaults().setValue(addEmail.text, forKey: "email")
 NSUserDefaults.standardUserDefaults().synchronize()
     */


}

So basically the data is not saving.

回答1:

You can store Array too, by this way

let userDefault = NSUserDefaults.standardUserDefaults()
let arr = ["abc","xyz","pqr"]
userDefault.setObject(arr, forKey: "arr")
userDefault.synchronize()

let data = userDefault.objectForKey("arr") as! [String]

回答2:

It is possible to store arrays in NSUserDefaults. But separating email and password in separate array is not suitable. You should store it as one object since they are related.

In your case an array of Dictionary objects is better, which is possible to store in NSUserDefaults as well, which you can retrieve as an array of Dictionary.

Here is the sample:

    let userDefault = NSUserDefaults.standardUserDefaults()

    var storedCredentials = userDefault.objectForKey("credentials") as? [[String:AnyObject]] ?? [[String:AnyObject]]()

    let email =
    [
        "email" : addEmail.text!,
        "password": addPassword.text!
    ]

    storedCredentials.append(email)

    userDefault.setObject(storedCredentials, forKey: "credentials")
    userDefault.synchronize()

回答3:

Save the Swift Array in Swift.

let kUserDefault = NSUserDefaults.standardUserDefaults()
kUserDefault.setObject(["KIRIT" , "MODI" , "FIRST" , "LAST"], forKey: "nameArray")
kUserDefault.synchronize()

Get Array

1. arrayForKey : You getting Swift Array

kUserDefault.arrayForKey("nameArray")!

2. objectForKey : You getting NSArray

kUserDefault.objectForKey("nameArray")!

3. valueForKey : You getting NSArray

kUserDefault.valueForKey("nameArray")

回答4:

You can't save an array of [String] in NSUserDefault, if you look at the documentation :

For NSArray and NSDictionary objects, their contents must be property list objects.

So what you can do is convert your [String] into NSData then save it into NSUserDefault.

// Store it as NSData
var emailData = [String]()
emailData.append("email1")
emailData.append("email2")
let emailIntoNSData = NSKeyedArchiver.archivedDataWithRootObject(emailData)
NSUserDefaults.standardUserDefaults().setObject(emailIntoNSData, forKey: "emailData")

// Retrieve it : 
let emailFromNSData = NSUserDefaults.standardUserDefaults().objectForKey("emailData") as? NSData
if let emailFromNSData = emailFromNSData {
let emailArray = NSKeyedUnarchiver.unarchiveObjectWithData(emailFromNSData) as? [String]
     if let emailArray = emailArray {
           NSLog("Email Data : \(emailArray)") // ["email1","email2"]
           // do something…
      }
 }

来源：https://stackoverflow.com/questions/36976066/how-to-store-array-in-nsuserdefault-in-swift

标签

ios

iphone

swift

nsuserdefaults