CODEWITHSUNDEEP
iosswiftfirebase
juelizabeth
juelizabeth

Reputation: 505

Organize firebase data by timestamp

I have some data in firebase that I am trying to organize by timestamp. I have incorporated this code into cellForRowAt

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        if let seconds = post["pub_time"] as? Double {
            let timeStampDate = NSDate(timeIntervalSince1970: seconds/1000)
            let dateFormatter = DateFormatter()
            dateFormatter.dateFormat = "MM/dd/yyyy"
            let formating = timeStampDate as Date


        let timeAgo = timeAgoSinceDate(formating)

            cell.Time.text = timeAgo

            posts.sort(by: { $0.timeStampDate.compare($1.timeStampDate) == .orderedAscending })


            }

But on the posts.sort(by: { $0.timeStampDate.compare($1.timeStampDate) == .orderedAscending }) I keep getting the error expression type bool is ambiguous without more context and I am not sure what I am doing wrong

This is more or less what my view controller looks like

    var posts = NSMutableArray()

    func loadData(){
        Database.database().reference().child("main").child("posts").queryOrdered(byChild: "pub_time").observeSingleEvent(of: .value, with: { snapshot in

                if let postsDictionary = snapshot .value as? [String: AnyObject] {
                    for post in postsDictionary {
                        posts.add(post.value)

                    }
                    self.TableView.reloadData()
                }

         })
    }

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        // Configure the cell...
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cells", for: indexPath) as! FeedTableViewCell

        //Configure the cell
let post = posts[indexPath.row] as! [String: AnyObject]
cell.Title.text = post["title"] as? String
 if let seconds = post["pub_time"] as? Double {
            let timeStampDate = NSDate(timeIntervalSince1970: seconds/1000)
            let dateFormatter = DateFormatter()
            dateFormatter.dateFormat = "MM/dd/yyyy"
            let formating = timeStampDate as Date


        let timeAgo = timeAgoSinceDate(formating)

            cell.Time.text = timeAgo



            }

        return cell
    }

Upvotes: 0

Views: 1059

Answers (1)

Jay
Jay

Reputation: 35659

Here's how you sort an array of objects in place; acending is the default order.

Assuming you have a PostClass like this

class PostClass {
   var timeStampDate = "" //assume the timestamps are yyyyMMddhhmmss strings
   var post = ""
}

and they are stored in a posts array

var posts = [PostClass]()

the code to sort the posts object within the array is:

posts.sort(by: {$0.timeStampDate < $1.timeStampDate })

that being said, you may want to consider letting Firebase do the heavy lifting and ordering the data for you so it's presented in the snapshot in the correct order.

Suppose you have a Firebase structure

posts
   post_0
     post: "A post about some stuff"
     timestamp: "2"
   post_1
     post: "Posting about how to post"
     timestamp: "3"
   post_2
     post: "The post for you"
     timestamp: "1"

and we want to load our posts, ordering by the timestamp

let postsRef = self.ref.child("posts")
let postQuery = postsRef.queryOrdered(byChild: "timestamp")
postQuery.observeSingleEvent(of: .value, with: { snapshot in
    for child in snapshot.children {
        let snap = child as! DataSnapshot
        let dict = snap.value as! [String: Any]
        let post = dict["post"] as! String
        let ts = dict["timestamp"] as! Int
        print(ts, post)
    }
})

and the output

1 The post for you
2 Posting about how to post
3 A post about some stuff

For this example, I used 1, 2, 3 as my timestamp but yyyyMMddhhmmss (20180618101000) format would work as well and provide human readable, proper ordering.

Upvotes: 1

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