解析"orderByDescending".询问 [英] Parse "orderByDescending" query
问题描述
我有两个叫Followers和Posts的类，我试图制作主屏幕，通过它我可以看到我关注的用户的帖子，也可以看到我的帖子..所以我尝试此操作以获取帖子查询:
I've two classes called Followers and Posts , I am trying to make the home screen by which i will be able to see the posts by the users i am following, and my posts too.. so i tried this to get the query of posts :
func loadData() {
var postQuery:PFQuery = PFQuery(className: "Posts")
postQuery.orderByDescending("createdAt")
postQuery.findObjectsInBackgroundWithBlock { (objects, error) -> Void in
if let objects = objects {
for object in objects {
self.data.addObject(object)
println(object.createdAt)
self.tableView.reloadData()
}
}
}
}
这里postQuery.orderByDescending("createdAt")正常工作..println(object.createdAt)给出了完美的结果:
here postQuery.orderByDescending("createdAt") is working fine.. println(object.createdAt) gives perfect result :
Optional(2015-08-25 22:31:12 +0000)
Optional(2015-08-25 22:28:28 +0000)
Optional(2015-08-25 22:25:36 +0000)
Optional(2015-08-24 13:40:48 +0000)
Optional(2015-08-24 13:39:25 +0000)
如果我也尝试查询关注的用户，就像这样:
and if i try to query followed users too , like this :
func loadData() {
let postsByCurrentUser = PFQuery(className: "Posts")
postsByCurrentUser.orderByAscending("createdAt")
postsByCurrentUser.whereKey("postedBy", equalTo: PFUser.currentUser()!)
postsByCurrentUser.findObjectsInBackgroundWithBlock ({ (objects, error) -> Void in
if let posts = objects as? [PFObject] {
for post in posts {
}
}
})
var posts:PFQuery = PFQuery(className: "Followers")
posts.whereKey("follower", equalTo: PFUser.currentUser()!)
posts.findObjectsInBackgroundWithBlock { (objects, error) -> Void in
if let objects = objects {
for object in objects {
var followedId = object["user"] as! PFObject
var postsByFollowedUser:PFQuery = PFQuery(className: "Posts")
postsByFollowedUser.whereKey("postedBy", equalTo: followedId)
postsByFollowedUser.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in
if let objects = objects {
for object in objects {
}
}
})
}
}
}
}
使用此代码，我得到帖子的随机顺序. 我在这里错在哪里..如果您需要任何有关该问题的解释，我可以给您，但请在这里帮助我..我找不到错误.基本上是这样:
using this code i'm getting a random order of the posts. where am i wrong here.. if you need any explanation about the question i can give you but help me out here.. i m not able to find the error. so basically :
-
我想根据时间获取orderByDescending中的帖子.
I want to get the posts in orderByDescending according to the time.
在这里，我正在获取用户的帖子，当前用户正在关注该帖子，但当前用户正在关注该帖子.我该怎么办?
Here i am getting the posts by the users which are being followed by the current user but the current user's posts. What should i do for that ?
推荐答案
所以这是完整的答案..
So here is complete answer ..
我知道这不是最理想的代码(您可以将其重构为方法)，但是它可以给您想要的结果...
I know it isn't the most optimal code ( u can refactor it into methods ) but it gives u wanted result ...
--- Sorted posts by current user
Optional(Test)
Optional(Test1)
Optional(Test2)
Optional(Test3)
Optional(Test4)
Optional(Test20)
--- Sorted posts by every follower
Optional(Test10)
Optional(Test11)
Optional(Test12)
完整的代码在这里:
override func viewDidLoad() {
super.viewDidLoad()
if PFUser.currentUser() != nil {
PFUser.logOut()
}
PFUser.logInWithUsernameInBackground("test", password: "test") { (let currentUser, let error) -> Void in
println("---")
// Insert test post
// let testPost = PFObject(className: "Posts")
// testPost["post"] = "Test20"
// let userRelation : PFRelation = testPost.relationForKey("postedBy")
// userRelation.addObject(PFUser.currentUser()!)
// testPost.saveEventually()
// Insert test relation
// let userToFollow = PFUser.query()
// userToFollow?.whereKey("username", equalTo: "test1")
// userToFollow?.findObjectsInBackgroundWithBlock({ (let result, let error) -> Void in
//
// if let follower = result!.first! as? PFUser {
//
// let followers = PFObject(className: "Followers")
// let userRelation : PFRelation = followers.relationForKey("user")
// userRelation.addObject(PFUser.currentUser()!)
// let followerRelation : PFRelation = followers.relationForKey("follower")
// followerRelation.addObject(follower)
//
// followers.saveEventually()
// }
// })
// Get posts by currentUser
let postsByCurrentUser = PFQuery(className: "Posts")
postsByCurrentUser.orderByAscending("createdAt")
postsByCurrentUser.whereKey("postedBy", equalTo: PFUser.currentUser()!)
postsByCurrentUser.findObjectsInBackgroundWithBlock({ (let pfPosts, let error) -> Void in
if let posts = pfPosts as? [PFObject] {
for post in posts {
println(post["post"])
}
}
})
// Get posts by followers
let postsByCurrentUserFollowers = PFQuery(className: "Followers")
postsByCurrentUserFollowers.whereKey("user", equalTo: PFUser.currentUser()!)
postsByCurrentUserFollowers.findObjectsInBackgroundWithBlock({ (let pfFollowers, let error) -> Void in
if let followers = pfFollowers as? [PFObject] {
for follower in followers {
let userFollowerRelation = follower.relationForKey("follower")
userFollowerRelation.query()!.findObjectsInBackgroundWithBlock({ (let followerToUser, let error) -> Void in
if let followerUser = followerToUser!.first! as? PFUser {
let postsByCurrentUser = PFQuery(className: "Posts")
postsByCurrentUser.orderByAscending("createdAt")
postsByCurrentUser.whereKey("postedBy", equalTo: followerUser)
postsByCurrentUser.findObjectsInBackgroundWithBlock({ (let pfPosts, let error) -> Void in
if let posts = pfPosts as? [PFObject] {
for post in posts {
println(post["post"])
}
}
})
}
})
}
}
})
}
}
这篇关于解析"orderByDescending".询问的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
