当我将以下Firebase数据库数据加载到tableView中时,数据按日期升序排序。如何通过降序排序(在顶部显示最新帖子)?
在Xcode中查询:
let ref = self.rootRef.child("posts").queryOrderedByChild("date").observeEventType(.ChildAdded, withBlock: { (snapshot) -> Void in
JSON导出:
"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" },
谢谢!!
编辑:下面的代码是整个解决方案,感谢Bawpotter
更新的查询:
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 } }
当Firebase将数据加载到tableView数据源数组中时,请调用此命令:
yourDataArray.sortInPlace({$0.date > $1.date})
Swift 3版本:
yourDataArray.sort({$0.date > $1.date})
Swift 4版本:
yourDataArray.sort(by: {$0.date > $1.date})