ios - 条件绑定(bind)的初始化程序必须具有可选类型，而不是 'String' - ios - swift

Question

这个错误的解决方案是什么？我尝试了所发现的，但无法解决我的问题。

错误在这里:

if var post = currentData.value as? [String : Any], let uid = Auth.auth().currentUser!.uid {

完整代码:

func incrementLikes(postId: String, onSucess: @escaping (Post) -> Void, onError: @escaping (_ errorMessage: String?) -> Void) {
        let postRef = Api.Post.REF_POSTS.child(postId)
        postRef.runTransactionBlock({ (currentData: MutableData) -> TransactionResult in
            if var post = currentData.value as? [String : Any], let uid = Auth.auth().currentUser!.uid {
                var likes: Dictionary<String, Bool>
                likes = post["likes"] as? [String : Bool] ?? [:]
                var likeCount = post["likeCount"] as? Int ?? 0
                if let _ = likes[uid] {
                    likeCount -= 1
                    likes.removeValue(forKey: uid)
                } else {
                    likeCount += 1
                    likes[uid] = true
                }
                post["likeCount"] = likeCount as AnyObject?
                post["likes"] = likes as AnyObject?

                currentData.value = post

                return TransactionResult.success(withValue: currentData)
            }
            return TransactionResult.success(withValue: currentData)
        }) { (error, committed, snapshot) in
            if let error = error {
                onError(error.localizedDescription)
            }
            if let dict = snapshot?.value as? [String: Any] {
                let post = Post.transformPostPhoto(dict: dict, key: snapshot!.key)
                onSucess(post)
            }
        }
    }

enter image description here

我不知道如何直接添加图片。抱歉

Answer 1

因为 Auth.auth().currentUser!.uid 返回一个 String，而不是 String?。如果你想执行条件检查，你应该使用

if let uid = Auth.auth().currentUser?.uid {
     //Logic here
}

如果你想将 Auth.auth().currentUser!.uid 的值分配给 uid，你应该在别处进行，而不是在 if 语句中