在Xcode 6.1（Swift）中将NSUserDefaults与suiteName一起使用时出现问题

Question

I'm having trouble using NSUserDefaults with suiteName in Xcode 6.1. This code worked previously, but now there is a Swift Compiler Error.

var userDefaults = NSUserDefaults(suiteName: "group.com.example.myAppGroup")
userDefaults.setObject("test", forKey: "test")

Swift Compiler Error: NSUserDefaults? does not have a member named 'setObject' NSUserDefaults? does not have a member named 'setObject'

When using standardUserDefaults() , it works as expected:

var userDefaults = NSUserDefaults.standardUserDefaults()
userDefaults.setObject("test", forKey: "test")

I'm not sure what I'm doing wrong when using suiteName .

Answer 1

That's because NSUserDefaults(suiteName:) returns an optional, as it says in the error message. So to fix, either you set your object this way:

userDefaults?.setObject("test", forKey: "test") // note the ? mark

or extract the value immediately from the initializer:

var userDefaults = NSUserDefaults(suiteName: "group.com.example.myAppGroup")! // note the ! mark

Answer 2

NSUserDefaults(suiteName:) returns an optional NSUserDefaults . You should use optional binding to make sure it's valid and unwrap it before using it:

if let userDefaults = NSUserDefaults(suiteName: "group.com.example.myAppGroup") {
    userDefaults.setObject("test", forKey: "test")
}