Question

我正在尝试通过firebase数据库对feedMessages进行注释，但是不知道如何在代码中实现上载/下载过程。如果我希望数据库看起来像显示的图像，该如何在邮件中上传/下载这些评论？

func getFeedMessages(handler: @escaping (_ feedMessages:[FeedMessages]) -> ()){
        var feedMessagesArray = [FeedMessages]()
        REF_FEEDMESSAGES.observeSingleEvent(of: .value) { (feedMessagesSnapshot) in
            guard let feedMessagesSnapshot = feedMessagesSnapshot.children.allObjects as? [DataSnapshot] else {return}

            for messages in feedMessagesSnapshot {
                let content = messages.childSnapshot(forPath: "content").value as? String ?? "Joe Flacco is an elite QB"
                let icon = messages.childSnapshot(forPath: "icon").value as? String ?? "none"
                let color = messages.childSnapshot(forPath: "color").value as? String ?? "bop"

                let messages = FeedMessages(content: content, color: color, icon: icon, votes: votes)
                feedMessagesArray.append(messages)
            }
            handler(feedMessagesArray)
        }
    }




 func uploadMessage(withContent content: String, withIcon icon: String, withColor color: String,sendComplete: @escaping (_ status: Bool) -> ()){
        REF_FEEDMESSAGES.childByAutoId().updateChildValues(["content" : content, "color" : color, "icon" : icon)
        sendComplete(true)
    }

desired Firebase database structure

Answer 1

您超级亲密！评论节点实际上只是每个消息节点中的子快照，因此您可以将其视为此类。

这是您的代码，带有额外的代码，可打印每个消息节点中的注释。

您需要添加错误检查和代码，以将其添加到FeedMessages。

feedMessagesRef.observeSingleEvent(of: .value) { feedMessagesSnapshot in
    guard let feedMessagesSnapshot = feedMessagesSnapshot.children.allObjects as? [DataSnapshot] else {return}

    for messages in feedMessagesSnapshot {
        let content = messages.childSnapshot(forPath: "content").value as? String ?? "Joe Flacco is an elite QB"
        let icon = messages.childSnapshot(forPath: "icon").value as? String ?? "none"
        let color = messages.childSnapshot(forPath: "color").value as? String ?? "bop"

        print(content, color, icon)

        let comments = messages.childSnapshot(forPath: "comments")
        for comment in comments.children {
            let commentSnap = comment as! DataSnapshot
            let aComment = commentSnap.value as! String
            print(aComment)
        }


        let messages = FeedMessages(content: content, color: color, icon: icon, votes: votes)
        feedMessagesArray.append(messages)
    }
}

编写节点是相同的思考过程-注释节点只是消息中的另一个键：值对，该值是一组键：值对。

在此示例中，我们使用字典来构建结构，然后编写节点

let feedMessagesRef = self.ref.child("feedMessages")

let messageDict:[String: Any] = [
    "content": "some content",
    "color": "some color",
    "icon": "an icon",
    "comments":
        ["comment_0": "a comment",
         "comment_1": "another comment"]
]

let aFeedMessage = feedMessagesRef.childByAutoId()
aFeedMessage.updateChildValues(messageDict)

如何通过Firebase实施评论

1 个答案: