Save custom objects into NSUserDefaults

I'm having a news ViewController and a TeamViewController. The TeamViewController contain a tableView of teamObjects which when selected is added into array. I want to add this array into NSUserDefaults so i can access them from the NewsController which contain a url request where the teamObjects is needed. However i keep getting:

'Attempt to insert non-property list object ( "" ) for key teams'

I'm open for other suggestions if there is better ways than storing it in NSUserDefaults

didSelectRowAtIndexPath method

override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
tableView.deselectRowAtIndexPath(indexPath, animated: true)




let team = self.teamArray[indexPath.row] as Team
var removed = false


for (index, value) in enumerate(self.teamSelected) {
if (value == team) {
self.teamSelected.removeAtIndex(index)
removed = true
}
}


if (!removed) {
self.teamSelected.append(team)
}


var userDefaults = NSUserDefaults.standardUserDefaults()
userDefaults.setValue(self.teamSelected, forKey: "teams")
userDefaults.synchronize()


tableView.reloadData()
}

My object

class Team: NSObject{
var id: Int!
var name: NSString!
var shortname: NSString!




init(id: Int, name:NSString, shortname: NSString) {
self.id = id
self.name = name
self.shortname = shortname


}


}
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小开

You can try NSKeyedUnarchiver, like below

Here i stored UIColor Object in UserDefault You can change it with your object 

 NSData *colorData = [NSKeyedArchiver archivedDataWithRootObject:color];
[[NSUserDefaults standardUserDefaults] setObject:colorData forKey:@"myColor"];

and to retrive that

NSData *colorData = [[NSUserDefaults standardUserDefaults] objectForKey:@"myColor"];
UIColor *color = [NSKeyedUnarchiver unarchiveObjectWithData:colorData];

Note : This is Objective C but I hope you can covert this in Swift

Hope this solve your problem

Update : Swift 5

Archive in Swift 

do{
let colorAsData = try NSKeyedArchiver.archivedData(withRootObject: UIColor.red, requiringSecureCoding: true)
UserDefaults.standard.set(colorAsData, forKey: "myColor")
UserDefaults.standard.synchronize()
}catch (let error){
#if DEBUG
print("Failed to convert UIColor to Data : \(error.localizedDescription)")
#endif
}

Unarchive in Swift

do{
if let colorAsData = UserDefaults.standard.object(forKey: "myColor") as? Data{
if let color = try NSKeyedUnarchiver.unarchivedObject(ofClasses: [UIColor.self], from: colorAsData){
// Use Color
}
}
}catch (let error){
#if DEBUG
print("Failed to convert UIColor to Data : \(error.localizedDescription)")
#endif
}
小开
最佳答案

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 = NSKeyedArchiver.archivedData(withRootObject: teams)
userDefaults.set(encodedData, forKey: "teams")

and unarchive it like this

let decoded  = userDefaults.data(forKey: "teams")
let decodedTeams = NSKeyedUnarchiver.unarchiveObject(with: decoded) as! [Team]

But if you just did that you will get

.Team encodeWithCoder:]: unrecognized selector sent to instance

You will have to make Team conform to NSCoding just like this

class Team: NSObject, NSCoding {
var id: Int
var name: String
var shortname: String




init(id: Int, name: String, shortname: String) {
self.id = id
self.name = name
self.shortname = shortname


}


required convenience init(coder aDecoder: NSCoder) {
let id = aDecoder.decodeInteger(forKey: "id")
let name = aDecoder.decodeObject(forKey: "name") as! String
let shortname = aDecoder.decodeObject(forKey: "shortname") as! String
self.init(id: id, name: name, shortname: shortname)
}


func encode(with aCoder: NSCoder) {
aCoder.encode(id, forKey: "id")
aCoder.encode(name, forKey: "name")
aCoder.encode(shortname, forKey: "shortname")
}
}

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