Firebase中的嵌套信息 [英] Nested information in Firebase

问题描述

如何访问处于更深层快照级别的信息？我是否总是需要启动另一个查询？为了向您展示我的意思，我有一个我的结构的屏幕截图：
DataStructure

我正在加载我的查询中的所有帖子，我可以阅读作者信息等，但是如何获取选项中的信息？我尝试了下面的内容：
$ b $ pre $ ref $ {$ c $ ref $在

中有{（snapshot：FIRDataSnapshot）如果snapshot.value ==零{
return
}
let post = Post（）
guard let snapshotValue = snapshot.value as？NSDictionary else {
return
}
post.postID = snapshot.key
post.title = snapshotValue [title] as？String
post.postDescription = snapshotValue [description] as？String
if（post.postDescription ==）{
post.postDescription =这个帖子没有描述

post.timestamp = snapshotValue [timestamp] as？NSNumber

let options = snapshotValue [options]
print（options）

当我打印选项时，可以看到这些信息，但是当我尝试将其转换为NSDictionary或其他东西o访问它，打印零？我也可以定义一个新的属性，如post.options，如果这可能有帮助？选项并不总是只有0和1，它的变量，所以我需要遍历这些。我怎样才能做到这一点？

解决方案

继续对原始问题的评论，您可以像下面这样访问选项值：

 如果让options = snapshotValue [options] as？ [任何] {
选项选项{
如果让optionDict =选项为？ [字符串：任何] {
让votes = optionDict [votes] as？ Int 
让url = optionDict [uri]为？字符串
} 
} 
} 
  

How can I access information that is in a "deeper" level of the snapshot? Do I always need to start another Query? To show you what I mean, I have a screenshot of my structure: Screenshot of DataStructure

I am loading all the posts in my query, I can read the author information etc, but how can I get the information inside options? I tried the following:

ref.child("posts").child("details").observe(.childAdded, with: { (snapshot:FIRDataSnapshot) in

        if snapshot.value == nil {
            return
        }
        let post = Post()
        guard let snapshotValue = snapshot.value as? NSDictionary else {
            return
        }
        post.postID = snapshot.key
        post.title = snapshotValue["title"] as? String
        post.postDescription = snapshotValue["description"] as? String
        if (post.postDescription == ""){
            post.postDescription = "No description has been entered for this post.."
        }
        post.timestamp = snapshotValue["timestamp"] as? NSNumber

        let options = snapshotValue["options"]
        print(options)

when I print options, I can see the information, but when I try to cast it to NSDictionary or something to access it, it prints nil? I can also define a new attribute like post.options if that may help? Options is not always just 0 and 1, its variable, so I need to iterate through those. How can I achieve that?

解决方案

Following up the comments on the original question, you can access the option values like this:

if let options = snapshotValue["options"] as? [Any] { 
    for option in options {
        if let optionDict = option as? [String:Any] {
            let votes = optionDict["votes"] as? Int
            let url = optionDict["uri"] as? String
        }
    }
}

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