james james - 3 months ago 319
iOS Question

Firebase query sort order in swift?

When I load the following Firebase Database data into my tableView, the data is sorted in ascending order by date. How can I order this by descending (show the newest post at the top)?

Query in Xcode:

let ref = self.rootRef.child("posts").queryOrderedByChild("date").observeEventType(.ChildAdded, withBlock: { (snapshot) -> Void in


JSON export:

"posts" : {
"-KMFYKt7rmfZINetx1hF" : {
"date" : "07/09/16 12:46 PM",
"postedBy" : "sJUCytVIWmX7CgmrypqNai8vGBg2",
"status" : "test"
},
"-KMFYZeJmgvmnqZ4OhT_" : {
"date" : "07/09/16 12:47 PM",
"postedBy" : "sJUCytVIWmX7CgmrypqNai8vGBg2",
"status" : "test"
},


Thanks!!

EDIT: Below code is the entire solution thanks to Bawpotter

Updated query:

let ref = self.rootRef.child("posts").queryOrderedByChild("date").observeEventType(.ChildAdded, withBlock: { (snapshot) -> Void in

let post = Post.init(key: snapshot.key, date: snapshot.value!["date"] as! String, postedBy: snapshot.value!["postedBy"] as! String, status: snapshot.value!["status"] as! String)

self.posts.append(post)

self.tableView.insertRowsAtIndexPaths([NSIndexPath(forRow: self.posts.count-1, inSection: 0)], withRowAnimation: .Automatic)


tableView cellForRowAtIndexPath

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("PostCell", forIndexPath: indexPath) as! PostCell

self.posts.sortInPlace({$0.date > $1.date})


Post.swift:

import UIKit

class Post {
var key: String
var date: String
var postedBy: String
var status: String

init(key: String, date: String, postedBy: String, status: String){
self.key = key
self.date = date
self.postedBy = postedBy
self.status = status
}
}

Answer

When Firebase loads the data into your tableView data source array, call this:

yourDataArray.sortInPlace({$0.date > $1.date})

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