I want to parse a JSON to object, but I have no idea how to cast AnyObject to String or Int since I'm getting:
0x106bf1d07: leaq 0x33130(%rip), %rax ; "Swift dynamic cast failure"
When using for example:
self.id = reminderJSON["id"] as Int
I have ResponseParser class and inside of it (responseReminders is an Array of AnyObjects, from AFNetworking responseObject):
for reminder in responseReminders {
let newReminder = Reminder(reminderJSON: reminder)
...
}
Then in Reminder class I'm initialising it like this (reminder as AnyObject, but is Dictionary(String, AnyObject)):
var id: Int
var receiver: String
init(reminderJSON: AnyObject) {
self.id = reminderJSON["id"] as Int
self.receiver = reminderJSON["send_reminder_to"] as String
}
println(reminderJSON["id"])
result is: Optional(3065522)
How can I downcast AnyObject to String or Int in case like this?
//EDIT
After some tries I come with this solution:
if let id: AnyObject = reminderJSON["id"] {
self.id = Int(id as NSNumber)
}
for Int and
if let tempReceiver: AnyObject = reminderJSON["send_reminder_to"] {
self.id = "\(tempReceiver)"
}
for string
In Swift, String
and Int
are not objects. This is why you are getting the error message. You need to cast to NSString
and NSNumber
which are objects. Once you have these, they are assignable to variables of the type String
and Int
.
I recommend the following syntax:
if let id = reminderJSON["id"] as? NSNumber {
// If we get here, we know "id" exists in the dictionary, and we know that we
// got the type right.
self.id = id
}
if let receiver = reminderJSON["send_reminder_to"] as? NSString {
// If we get here, we know "send_reminder_to" exists in the dictionary, and we
// know we got the type right.
self.receiver = receiver
}
reminderJSON["id"]
gives you an AnyObject?
, so you cannot cast it to Int
You have to unwrap it first.
Do
self.id = reminderJSON["id"]! as Int
if you're sure that id
will be present in the JSON.
if id: AnyObject = reminderJSON["id"] {
self.id = id as Int
}
otherwise
Now you just need to import foundation
. Swift will convert value type(String,int)
into object types(NSString,NSNumber)
.Since AnyObject works with all objects now compiler will not complaint.
This is actually pretty simple, the value can be extracted, casted, and unwrapped in one line: if let s = d["2"] as? String
, as in:
var d:[String:AnyObject] = [String:AnyObject]()
d["s"] = NSString(string: "string")
if let s = d["s"] as? String {
println("Converted NSString to native Swift type")
}
来源:https://stackoverflow.com/questions/25449080/swift-anyobject-is-not-convertible-to-string-int