在Swift中将项目添加到Firebase数组，而不先观察阵列 [英] Adding items to Firebase array in Swift without observing for array first

问题描述

目前，我通过观察数组，首先添加一个新的帖子到我的Firebase数组，然后添加新的帖子，然后更新ref：

  REF_USER.child（UID）.observeSingleEventOfType（.Value，withBlock：{snapshot in 
 if！snapshot.exists（）{return} 
如果让dict = snapshot.value as？Dictionary< ; String，AnyObject> ;, 
 let posts = dict [postsas？[String] {
 posts.append（newPost）
 REF_USER.child（UID +/ posts）。 setValue（posts）
} 
} 
  

有没有办法跳过观察的步骤，并立即更新数组中的帖子？假设是这样的：

  REF_USER .child（UID +/posts\").addToArray(newPost）
  

解决方案

在Firebase中避免使用数组是非常好的做法，因为它们非常难以处理;单个元素不能直接访问，而且可以不更新 - 他们必须重写。

不知道为什么你要通过问题中列出的步骤来添加一个新的职位，但这里有另一个解决方案：

  thisPostRef = postsRef.childByAutoId //创建一个新的帖子节点
 thisPostRef.setValue（这是一个新帖子）//将帖子存入其中
  

编辑：

这会产生这样的结构

 文章
 post_id_0：这是新文章
 post_id_1：另一篇文章
 post_id_2：cool post
  

这个结构避免了数组的缺陷。
$ b

另一个编辑。 OP询问如何将其写入用户/ UID /帖子节点

$ $ $ $ $ c $ usersRef = rootRef.childByAppendingPath（users）
thisUserRef = usersRef.childByAppendingPath（users uid）
thisUserPostRef = thisUserRef.childByAutoId //创建一个新的帖子节点
thisUserPostRef.setValue（这是一个新帖子）//将帖子存入它

Currently I add a new post to my Firebase array by observing for the array first, appending my new post, and then updating the ref:

REF_USER.child(UID).observeSingleEventOfType(.Value, withBlock: { snapshot in
   if !snapshot.exists() {return}
   if let dict = snapshot.value as? Dictionary<String, AnyObject>, 
      let posts = dict["posts" as? [String] {
      posts.append(newPost)
      REF_USER.child(UID + "/posts").setValue(posts)
   }
}

Is there a way to skip the step of observing, and straight away update posts in an array? Hypothetically, something like:

REF_USER.child(UID + "/posts").addToArray(newPost)

解决方案

It's generally good practice to avoid array's in Firebase as they are super hard to deal with; the individual elements cannot be accessed directly and they cannot be updated - they have to be re-written.

Not sure why you are going through the steps outlined in your question to add a new post but here's another solution:

thisPostRef = postsRef.childByAutoId //create a new post node
thisPostRef.setValue("here's a new post") //store the post in it

Edit:

This will result in a structure like this

posts
  post_id_0: "here's a new post"
  post_id_1: "another post"
  post_id_2: "cool post"

This structure avoids the pitfalls of arrays.

Another edit. The OP asks how to write it to the users/UID/posts node

usersRef = rootRef.childByAppendingPath("users")
thisUserRef = usersRef.childByAppendingPath(the users uid)
thisUserPostRef = thisUserRef.childByAutoId //create a new post node
thisUserPostRef.setValue("here's a new post") //store the post in it

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