Firebase数据库的indexPath [英] Firebase Database indexPath
本文介绍了Firebase数据库的indexPath的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我尝试使用这个函数从firebase中检索数据，但是我没有得到所有的数据：
func （_ completionBlock：@escaping（_ success：Bool，_ error：Error？） - >（））{
let userMessagesRef = DataService.instance.REF_ARTISTARTS.child（Auth.auth（）。currentUser !. uid）
如果让snapshot = snapshot.children.allObjects as？[DataSnapshot]
$ b userMessagesRef.observe（.childAdded，其中：{[weak self] {
print（SNAPSHOT：（snapshot.count））= 12
}
guard let strongSelf = self else {return}
guard让dictionary = snapshot.value as？[String：AnyObject] else {
completionBlock（false，nil）
return
}
var arts = [Art ？]（）
如果让art = ArtViewModelController.parse（字典）{
arts.append（art）
print（arts.count）= 1
<
strongSelf.viewModels = ArtViewModelController.initViewModels（arts）
completionBlock（true，nil）
}）{（error：Error） b completionBlock（false，error）
}
}
var viewModelsCount：Int {
return viewModels.count
}
func viewModel（at index：Int） - > ArtViewModel？ {
保护索引< = 0&&索引< viewModelsCount else {return nil}
return viewModels [index]
}
}
私有扩展ArtViewModelController {
static func parse（_ dictionary：[String：Any]） - >艺术？ {
让artID = dictionary [artID]为？字符串？
let imgUrl = dictionary [imageUrl] as？字符串？
let title = dictionary [title] as？字符串？
let description = dictionary [description] as？字符串？
let price = dictionary [price] as？ NSNumber？ 0
let type = dictionary [type] as？字符串？
let height = dictionary [height] as？ NSNumber？ 0
let width = dictionary [width] as？ NSNumber？ 0
让postDate = dictionary [postDate] as？ NSNumber？ 0
return Art（artID：artID，imgUrl：imgUrl，price：price，title：title，description：description，type：type，height：height，width：width，postDate：postDate）
}
static func initViewModels（_ arts：[Art？]） - > [ArtViewModel？] {
print（SECOND VIDEO COUNT：\（arts.count））
return arts.map {art in
if art = art {
返回ArtViewModel（art：art）
} else {
return nil
}
}
}
$ b $ p 我的问题是我的index.count总是等于1，但它应该等于12 。
原始代码如下：
$ b $ pre $ func retrieveUsers（_ completionBlock ：@escaping（_ success：Bool，_ error：NSError？） - >（））{
let urlString =http：// localhost：3000 / users
let session = URLSession.shared
$ b guard让url = URL（string：urlString）else {
completionBlock（false，nil）
return
}
let task = session.dataTask （with：url）{[weak self]（data，response，error）in
guard let strongSelf = self else {return}
guard let data = data e lse {
completionBlock（false，错误为NSError？）
return
}
let error = NSError.createError（0，description：JSON parsing error）
如果让jsonData =尝试？ JSONSerialization.jsonObject（与：数据，选项：.allowFragments）为？ [[String：AnyObject]] {
guard let jsonData = jsonData else {
completionBlock（false，error）
return
}
var users = [User？] （）
jsonData中的json {
if let user = UserViewModelController.parse（json）{
users.append（user）
}
}
strongSelf.viewModels = UserViewModelController.initViewModels（users）
completionBlock（true，nil）
} else {
completionBlock（false，error）
}
}
task.resume（）
}
做同样的事情，但与Firebase。如果您需要更多的细节，请询问！
SNAPSHOT PRINT：
SNAPSHOT：可选（{
description =是;
height = 87;
imageUrl =https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot的.com / O /艺术％2F4bjurh5FFNOUb2D4oHGfRqEm7Il2％2FB6E2A9F0-C409-4732-B6D9-14382E6796F5 ALT =媒体&安培;标记= 32992b9c-4a08-456d-8950-119f681b4cdc;
踵= 1498921599547;
价格= 23;
private = 0;
title =Yes;
type = Modern;
userUID = 4bjurh5FFNOUb2D4oHGfRqEm7Il2;
width = 71;
}）
SNAPSHOT：可选（{
artHeight = 85;
artWidth = 123;
description =Yes;
height = 85;
imageUrl = https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F16280189-5AEA-47CB-9251-C95635FFE56C?alt=media&token=8198df4e-da8c-4883- b278-fc7c14730f69;
postDate = 1498921623601;
price = 23;
private = 0;
title =blacks don'\\U2019t Crack;
type = Abstract;
userUID = 4bjurh5FFNOUb2D4oHGfRqEm7Il2;
width = 123; （
）
SNAPSHOT：可选（{
artHeight = 81;
artWidth = 11;
description =Yes;
height = 81;
IMAGEURL =https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F305FDE5C-1C5C-4ABD-B4A1-4FA224421202?alt=media&token= fcba57df-e252-47c2-be92-7836bd97e6fe;
postDate = 1502242913081;
price = 23;
private = 0;
title =Title;
type = type;
userUID = 4bjurh5FFNOUb2D4oHGfRqEm7Il2;
width = 118;
}）
SNAPSHOT：可选（{
description =Hey;
height = 82，
IMAGEURL =https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F04B00727-2AE4-41E3-BCA3-3980182C7F67?alt=media& ;令牌= cc1d6a92-1625-453c-bf1f-2ec84d6df51a;
postDate = 1503341277594;
price = 23;
private = 0;
title =Title;
type = Modern;
userUID = 4bjurh5FFNOUb2D4oHGfRqEm7Il2;
width = 124;
$）
DIC：[height：87，private：0，width：71，postDate ：1498921599547， 说明：是的， 头衔：是的， IMAGEURL：https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2FB6E2A9F0-C409 -4732-B6D9-14382E6796F5 ALT =媒体&安培;标记= 32992b9c-4a08-456d-8950-119f681b4cdc， userUID？：4bjurh5FFNOUb2D4oHGfRqEm7Il2， 价格：23， 类型：现代]
DIC：[artWidth ：123，height：85，private：0，artHeight：85，description：是，postDate：1498921623601，width：123，imageUrl：https：// firebasestorage。 googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oH4RHFRqEm7Il2%2F16280189-5AEA-47CB-9251-C95635FFE56C?alt=media&token=8198df4e-da8c-4883-b278-fc7c14730f69title ：blacks不破解，price：23，type：摘要，userUID：4bjurh5FFNoub2D4oHGfRqEm7Il2]
DIC：[artWidth：11，height：81，private：0 ，artHeight：81，说明：是，postDate：150224 2913081， 宽度：118， IMAGEURL：https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F305FDE5C-1C5C-4ABD-B4A1-4FA224421202？ ALT =媒体&安培;标记= fcba57df-e252-47c2-be92-7836bd97e6fe， 标题：标题， 价格：23， 类型：类型， userUID：4bjurh5FFNOUb2D4oHGfRqEm7Il2]
DIC：[ 高度 ：82，private：0，width：124，postDate：1503341277594，description：嘿，title：标题，imageUrl：https：//firebasestorage.googleapis.com/v0/b /medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F04B00727-2AE4-41E3-BCA3-3980182C7F67?alt=media&token=cc1d6a92-1625-453c-bf1f-2ec84d6df51a，userUID：4bjurh5FFNOUb2D4oHGfRqEm7Il2，price ：23，type：Modern]
解决方案
： -
func retrieveVideos（_ completionBlock：@escaping（_ success：Bool，_ error：Error？） - > （））{
let userMessagesRef = DataService.instance.REF_ARTISTARTS.child（Auth.auth（）。currentUser！.uid）
userMessagesRef.observe（.value，with：{[weak （快照）（snapshots.count））
（$） b
$ b var arts = [Art]（）
guard let strongSelf = self else {return}
快照中的快照{
let dictionary = snapshot.value as？[String：AnyObject]
如果让art = ArtViewModelController.parse（dictionary）{
arts。 append（art）
}
}
strongSelf.viewModels = ArtViewModelController.initViewModels（arts）
completionBlock（true，nil）
} $ {
completionBlock（false，error）
} $ { b $ b}
I'm trying to retrieve data from firebase using this function but I'm not getting all the data:
func retrieveVideos(_ completionBlock: @escaping (_ success: Bool, _ error: Error?) -> ()) {
let userMessagesRef = DataService.instance.REF_ARTISTARTS.child(Auth.auth().currentUser!.uid)
userMessagesRef.observe(.childAdded, with: { [weak self] (snapshot) in
if let snapshot = snapshot.children.allObjects as? [DataSnapshot] {
print("SNAPSHOT: (snapshot.count)") = 12
}
guard let strongSelf = self else {return}
guard let dictionary = snapshot.value as? [String: AnyObject] else {
completionBlock(false, nil)
return
}
var arts = [Art?]()
if let art = ArtViewModelController.parse(dictionary) {
arts.append(art)
print(arts.count) = 1
}
strongSelf.viewModels = ArtViewModelController.initViewModels(arts)
completionBlock(true, nil)
}) { (error: Error) in
completionBlock(false, error)
}
}
var viewModelsCount: Int {
return viewModels.count
}
func viewModel(at index: Int) -> ArtViewModel? {
guard index <= 0 && index < viewModelsCount else { return nil }
return viewModels[index]
}
}
private extension ArtViewModelController {
static func parse(_ dictionary: [String: Any]) -> Art? {
let artID = dictionary["artID"] as? String ?? ""
let imgUrl = dictionary["imageUrl"] as? String ?? ""
let title = dictionary["title"] as? String ?? ""
let description = dictionary["description"] as? String ?? ""
let price = dictionary["price"] as? NSNumber ?? 0
let type = dictionary["type"] as? String ?? ""
let height = dictionary["height"] as? NSNumber ?? 0
let width = dictionary["width"] as? NSNumber ?? 0
let postDate = dictionary["postDate"] as? NSNumber ?? 0
return Art(artID: artID, imgUrl: imgUrl, price: price, title: title, description: description, type: type, height: height, width: width, postDate: postDate)
}
static func initViewModels(_ arts: [Art?]) -> [ArtViewModel?] {
print("SECOND VIDEO COUNT: \(arts.count)")
return arts.map { art in
if let art = art {
return ArtViewModel(art: art)
} else {
return nil
}
}
}
}
My problem is that my index.count is always equal to 1 but it's supposed to equal to 12.
Here's the original code:
func retrieveUsers(_ completionBlock: @escaping (_ success: Bool, _ error: NSError?) -> ()) {
let urlString = "http://localhost:3000/users"
let session = URLSession.shared
guard let url = URL(string: urlString) else {
completionBlock(false, nil)
return
}
let task = session.dataTask(with: url) { [weak self] (data, response, error) in
guard let strongSelf = self else { return }
guard let data = data else {
completionBlock(false, error as NSError?)
return
}
let error = NSError.createError(0, description: "JSON parsing error")
if let jsonData = try? JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [[String: AnyObject]] {
guard let jsonData = jsonData else {
completionBlock(false, error)
return
}
var users = [User?]()
for json in jsonData {
if let user = UserViewModelController.parse(json) {
users.append(user)
}
}
strongSelf.viewModels = UserViewModelController.initViewModels(users)
completionBlock(true, nil)
} else {
completionBlock(false, error)
}
}
task.resume()
}
So I'm trying to do the same thing but with Firebase. If you need more details please just ask!
SNAPSHOT PRINT:
SNAPSHOT: Optional({
description = "Yes ";
height = 87;
imageUrl = "https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2FB6E2A9F0-C409-4732-B6D9-14382E6796F5?alt=media&token=32992b9c-4a08-456d-8950-119f681b4cdc";
postDate = 1498921599547;
price = 23;
private = 0;
title = "Yes ";
type = Modern;
userUID = 4bjurh5FFNOUb2D4oHGfRqEm7Il2;
width = 71;
})
SNAPSHOT: Optional({
artHeight = 85;
artWidth = 123;
description = "Yes ";
height = 85;
imageUrl = "https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F16280189-5AEA-47CB-9251-C95635FFE56C?alt=media&token=8198df4e-da8c-4883-b278-fc7c14730f69";
postDate = 1498921623601;
price = 23;
private = 0;
title = "blacks don\U2019t Crack ";
type = Abstract;
userUID = 4bjurh5FFNOUb2D4oHGfRqEm7Il2;
width = 123;
})
SNAPSHOT: Optional({
artHeight = 81;
artWidth = 11;
description = "Yes ";
height = 81;
imageUrl = "https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F305FDE5C-1C5C-4ABD-B4A1-4FA224421202?alt=media&token=fcba57df-e252-47c2-be92-7836bd97e6fe";
postDate = 1502242913081;
price = 23;
private = 0;
title = "Title ";
type = type;
userUID = 4bjurh5FFNOUb2D4oHGfRqEm7Il2;
width = 118;
})
SNAPSHOT: Optional({
description = "Hey ";
height = 82;
imageUrl = "https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F04B00727-2AE4-41E3-BCA3-3980182C7F67?alt=media&token=cc1d6a92-1625-453c-bf1f-2ec84d6df51a";
postDate = 1503341277594;
price = 23;
private = 0;
title = "Title ";
type = Modern;
userUID = 4bjurh5FFNOUb2D4oHGfRqEm7Il2;
width = 124;
})
DIC: ["height": 87, "private": 0, "width": 71, "postDate": 1498921599547, "description": Yes , "title": Yes , "imageUrl": https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2FB6E2A9F0-C409-4732-B6D9-14382E6796F5?alt=media&token=32992b9c-4a08-456d-8950-119f681b4cdc, "userUID": 4bjurh5FFNOUb2D4oHGfRqEm7Il2, "price": 23, "type": Modern]
DIC: ["artWidth": 123, "height": 85, "private": 0, "artHeight": 85, "description": Yes , "postDate": 1498921623601, "width": 123, "imageUrl": https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F16280189-5AEA-47CB-9251-C95635FFE56C?alt=media&token=8198df4e-da8c-4883-b278-fc7c14730f69, "title": blacks don’t Crack , "price": 23, "type": Abstract, "userUID": 4bjurh5FFNOUb2D4oHGfRqEm7Il2]
DIC: ["artWidth": 11, "height": 81, "private": 0, "artHeight": 81, "description": Yes , "postDate": 1502242913081, "width": 118, "imageUrl": https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F305FDE5C-1C5C-4ABD-B4A1-4FA224421202?alt=media&token=fcba57df-e252-47c2-be92-7836bd97e6fe, "title": Title , "price": 23, "type": type, "userUID": 4bjurh5FFNOUb2D4oHGfRqEm7Il2]
DIC: ["height": 82, "private": 0, "width": 124, "postDate": 1503341277594, "description": Hey , "title": Title , "imageUrl": https://firebasestorage.googleapis.com/v0/b/medici-b6f69.appspot.com/o/Art%2F4bjurh5FFNOUb2D4oHGfRqEm7Il2%2F04B00727-2AE4-41E3-BCA3-3980182C7F67?alt=media&token=cc1d6a92-1625-453c-bf1f-2ec84d6df51a, "userUID": 4bjurh5FFNOUb2D4oHGfRqEm7Il2, "price": 23, "type": Modern]
解决方案
Use This: -
func retrieveVideos(_ completionBlock: @escaping (_ success: Bool, _ error: Error?) -> ()) {
let userMessagesRef = DataService.instance.REF_ARTISTARTS.child(Auth.auth().currentUser!.uid)
userMessagesRef.observe(.value, with: { [weak self] (snapshot) in
if let snapshots = snapshot.children.allObjects as? [DataSnapshot]
{
print("SNAPSHOT: (snapshots.count)")
}
var arts = [Art]()
guard let strongSelf = self else {return}
for snapshot in snapshots {
let dictionary = snapshot.value as? [String: AnyObject]
if let art = ArtViewModelController.parse(dictionary) {
arts.append(art)
}
}
strongSelf.viewModels = ArtViewModelController.initViewModels(arts)
completionBlock(true, nil)
}) { (error: Error) in
completionBlock(false, error)
} }
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