Swift creating NSError Object

Ehab Saifan picture Ehab Saifan · Oct 15, 2015 · Viewed 37.4k times · Source

I am trying to create an error object to display to the user.

let userInfo: [NSObject : AnyObject] = 
    [
    "NSLocalizedDescriptionKey" :  NSLocalizedString("Unauthorized", comment: ""),
    "NSLocalizedFailureReasonErrorKey" : NSLocalizedString("Unauthorized", comment: "")
    ]
let err = NSError(domain: "ShiploopHttpResponseErrorDomain", code: httpResponse.statusCode, userInfo: userInfo)
print("Error in Post: \(err.localizedDescription)")

Unfortunately the output is:

Error in Post: The operation couldn’t be completed.(ShiploopHttpResponseErrorDomain error 401.) 

I want to be able to show to the user that he should activate his account. Any ideas??

Answer

ProgrammierTier picture ProgrammierTier · Oct 15, 2015

Looks like you want (see dictionary keys):

Swift 2

let userInfo: [NSObject : AnyObject] =
[
    NSLocalizedDescriptionKey :  NSLocalizedString("Unauthorized", value: "Please activate your account", comment: ""),
    NSLocalizedFailureReasonErrorKey : NSLocalizedString("Unauthorized", value: "Account not activated", comment: "")
]

Swift 3

let userInfo: [AnyHashable : Any] =
            [
                NSLocalizedDescriptionKey :  NSLocalizedString("Unauthorized", value: "Please activate your account", comment: "") ,
                NSLocalizedFailureReasonErrorKey : NSLocalizedString("Unauthorized", value: "Account not activated", comment: "")
        ]

Then create the error object in both swift 2 or 3 like this:

let err = NSError(domain: "ShiploopHttpResponseErrorDomain", code: 401, userInfo: userInfo)
println("Error in Post: \(err.localizedDescription)")

NSLocalizedDescriptionKey and NSLocalizedFailureReasonErrorKey are global String variables, and the keys inside of the userInfo dictionary. The values are slightly different from what you specified:

println(NSLocalizedDescriptionKey) //prints "NSLocalizedDescription"
println(NSLocalizedFailureReasonErrorKey) //prints "NSLocalizedFailureReason"

I find it good practice to look at the documentation by right-clicking the class (NSError in this case) and selecting "Jump To Definition" within xcode. All kinds of questions can be answered this way. :)