ios – Swift无法通过下标分配：下标仅获取

我对 Swift语法相当新,并且我的代码“无法通过下标分配：下标仅获取”,我收到此错误

这是从行：friendDictionary [(friendUID as？String)！] = [“name”：friendsData！[“name”]]

任何关于正确方法的建议都会非常有帮助.

func getFriendsUIDs() {

        if FBSDKAccessToken.currentAccessToken() == nil {

            print("failed to start graph request")
            return

        }else{
        }


        if FBSDKAccessToken.currentAccessToken() != nil {
        }

let parameters = ["fields": "name,id,picture"]
FBSDKGraphRequest(graphPath: "/me/friends",parameters: parameters).startWithCompletionHandler {
(NSURLConnection,result,requestError) in
let friendIds = result["id"] as? NSDictionary
let friendsData = friendIds!["data"] as? [NSDictionary]

        var ref: FIRDatabaseReference!
        ref = FIRDatabase.database().reference()
        ref.child("users").child((FIRAuth.auth()?.currentUser?.uid)!).child("friendUIDs").observeEventType(.Value,withBlock: { (snapshot) in
            self.FriendUIDs = NSArray()
            self.FriendUIDs = (snapshot.value as? NSArray)!
            print(self.FriendUIDs)
            var friendDictionary = NSDictionary()
            for friendUID in self.FriendUIDs {
                friendDictionary[(friendUID as? String)!]  = ["name": friendsData!["name"]]
            }

            self.fetchFriendFeed(friendDictionary)
        }) { (error) in
            print(error.localizedDescription)
        }
}

}



func fetchFriendFeed(friendDictionary: NSDictionary) {


var ref: FIRDatabaseReference!
ref = FIRDatabase.database().reference()

for friendUID in FriendUIDs {

    ref.child("users").child(friendUID as! String).child("Agenda").observeEventType(.ChildAdded,withBlock: { (snapshot) in

        print(snapshot)
        if let dictionary = snapshot.value as? [String: AnyObject] {
            let friendPost = FriendPost()
            friendPost.picture = friendDictionary[friendUID as! String]? ["picture"] as? String
            friendPost.activity = dictionary["activity"] as? String
            friendPost.date = dictionary["date"] as? String
            friendPost.time = dictionary["time"] as? String
            friendPost.friendname = friendDictionary[friendUID as! String]?  ["name"] as? String
            self.friendPosts.append(friendPost)

            dispatch_async(dispatch_get_main_queue(),{
                self.collectionView?.reloadData()

解决方法

与Swift无关.您已经选择使用Objective-C,实际上是将friendDictionary设为NSDictionary. NSDictionary是不可变的;你不能分配或以任何方式改变它.这只是关于Objective-C的一个事实. Swift var声明对这个事实没有任何影响.

一个更好的选择,因为你在Swift中编写,将使用Swift字典,它是[AnyHashable：Any]()(在Swift 3中).当你与Objective-C交谈时,这将与NSDictionary交换,但它会给你一个可变字典,因为你(正确地)用var声明了它.