iOS SWIFT-NSJSONSerialization后的JSON对象为nil

Question

hello I am trying to read JSON as an array from the server not the dictionary. If I do this

let json: NSArray?
do {
    json = try NSJSONSerialization.JSONObjectWithData(data!, options: .AllowFragments) as! NSArray
    print("json is \(json)")
}

json object comes nil through this code and also I can't access the variable like this json["code"] I have tried this too

NSJSONSerialization.JSONObjectWithData(data!, options: .MutableLeaves) as! NSArray

But If I don't specify any type and let the variable as AnyObject

do {
    let json = try NSJSONSerialization.JSONObjectWithData(data!, options: .AllowFragments)
    print("json is \(json["code"]!)")                    
} 

It works But 1st problem here is it prints Optional in the debugger but its least of my worries compared to that I can't do something like this

if json["code"] == 200 { 

}

If I do this it says

Binary operator '==' cannot by applied to operands of type Anyobject? and Int

what I want is to get the data in NSArray . I don't want the json variable to be set as AnyObject . Inshort I want this code to work

let json: NSArray?
do {
    json = try NSJSONSerialization.JSONObjectWithData(data!, options: .AllowFragments) as! NSArray
    print("json is \(json)")
} 

if its possible. I don't know what I am doing wrong here

json:

 {"code":200,"msg":"login success"}

Answer 1

If printing json["code"] works, then json is doubtless a dictionary.

JSONObjectWithData returns AnyObject that is "I-have-no-idea-what-it-is-but-it-is-some-kind-of-object-and-not-a-value" (thanks to gnasher729 for the more accurate paraphrase of AnyObject )

Since you know the object is [String:AnyObject] cast the type

let json = try NSJSONSerialization.JSONObjectWithData(data!, options: .AllowFragments) as! [String:AnyObject]

Then get the code – which is an Int – with

if json["code"] as! Int == 200 { 

}

or with optional binding if the key is optional

if let code = json["code"] as? Int { 
   if code == 200 {

   }
}