如何获取多个用户帖子？

Question

我有多个用户，我希望显示他们发布的每个图像或视频...现在问题是，在firebase数据库中只添加了最后一个ID我尝试了不同的方法和算法，没有看到工作

var friendsArray = [String]()
    var fetchID : String?
    for i in 0...friendsArray.count{
        friendsArray.append(fetchFriend.id!)
      let id = friendsArray[i]
        fetchID = id
    }

    print(fetchID)
    FIRDatabase.database().reference().child("users").child(fetchID!).observeEventType(.ChildAdded, withBlock: { (snapshot) in

        var videos = [Video]()
        for child in snapshot.children {
            let dictionary = snapshot.childSnapshotForPath(child.key)

            let userChannel = UserChannel()
            userChannel.profileImageName = fetchFriend.profileImage
            userChannel.username = fetchFriend.username
            let video = Video()
            video.thumbnailImageName = dictionary.value!["imageURL"] as? String
            video.userChannel = userChannel
            videos.append(video)
            videos = videos.reverse()
            dispatch_async(dispatch_get_main_queue(),{
            completion(videos)
       })
    }

  }, withCancelBlock:nil)
}