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.