Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
570 views
in Technique[技术] by (71.8m points)

ios - 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})
        self.tableView.reloadData()

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
    }
}
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)
Waitting for answers

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...