Error while retrieving data from parse.com - ios

Question

Hello I want to get some data from my parse.com class called "Tags" in this class there are two 3 cols "objectID", "username" and "tagtext". I want to read a record finding by ID and afterwords I want to save "useername" and "tagtext" into two strings. I have done it like it is in the parse.com documentation:
#IBAction func readAction(sender: UIButton) {
var query = PFQuery(className:"Tags")
query.getObjectInBackgroundWithId("IsRTwW1dHY") {
(gameScore: PFObject?, error: NSError?) -> Void in
if error == nil && gameScore != nil {
println(gameScore)
} else {
println(error)
}
}
let username = gameScore["username"] as! String
let tagtext = gameScore["tagtext"] as! String
println(username)
println(tagtext)
}
I get an error called fatal error: unexpectedly found nil while unwrapping an Optional value , please tell me what is wrong in my code.
My class:

Answer 1

The problem is that:
let username = gameScore["username"] as! String
let tagtext = gameScore["tagtext"] as! String
gameScore["username"] and gameScore["tagtext"] can return nil values, and when you say as! String you say that it will be a String, and it is nil.
Try something like:
let username = gameScore["username"] as? String
let tagtext = gameScore["tagtext"] as? String
your error is happening because of that, but your final code should look like this:
#IBAction func readAction(sender: UIButton) {
var query = PFQuery(className:"Tags")
query.getObjectInBackgroundWithId("f3AXazT9JO") {
(gameScore: PFObject?, error: NSError?) -> Void in
let username = gameScore["username"] as? String
let tagtext = gameScore["tagtext"] as? String
println(username)
println(tagtext)
if error == nil && gameScore != nil {
println(gameScore)
} else {
println(error)
}
}
}
Because the getObjectInBackgroundWithId is async.

Answer 2

You are trying to read from your response object gameScore but it is still nil because getObjectInBackgroundWithId is an asynchronous method meaning that it will return a result once it is finished. Put the two lines inside the handler and start from there.