【发布时间】：2021-08-06 05:54:11
【问题描述】：
我已经简化了我的代码，以便更容易看到我正在尝试做什么，我正在构建一个评分源，这些评分来自我“关注”的任何人的 firebase 文档
我想做的就是每当 firebase 说我的一条评论有新更新时，更改 Identifiable，而不是重新加载我关注的每个人的每条评论。
这是我的观点：
import SwiftUI
import Firebase
struct Rating: Identifiable {
var id: String
var review: String
var likes: Int
}
struct Home: View {
@ObservedObject var feedViewModel = FeedViewModel()
var body: some View {
VStack{
ForEach(self.feedViewModel.allRatings, id: \.id){ rating in
Text(rating.review)
Text("\(rating.likes)")
}
}
}
}
这是我的 FeedViewModel 函数：
class FeedViewModel: ObservableObject {
@Published var following = ["qedXpEcaRLhIa6zWjfJC", "1nDyDT4bIa7LBEaYGjHG", "4c9ZSPTQm2zZqztNlVUp", "YlvnziMdW8VfibEyCUws"]
@Published var allRatings = [Rating]()
init() {
for doc in following {
// For each person (aka doc) I am following we need to load all of it's ratings and connect the listeners
getRatings(doc: doc)
initializeListener(doc: doc)
}
}
func getRatings(doc: String) {
db.collection("ratings").document(doc).collection("public").getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
// We have to use += because we are loading lots of different documents into the allRatings array, allRatings turns into our feed of reviews.
self.allRatings += querySnapshot!.documents.map { queryDocumentSnapshot -> Rating in
let data = queryDocumentSnapshot.data()
let id = ("\(doc)-\(queryDocumentSnapshot.documentID)")
let review = data["review"] as? String ?? ""
let likes = data["likes"] as? Int ?? 0
return Rating(id: id, review: review, likes: likes)
}
}
}
func initializeListener(doc: String){
db.collection("ratings").document(doc).collection("public")
.addSnapshotListener { (querySnapshot, error) in
guard let snapshot = querySnapshot else {
print("Error listening for channel updates")
return
}
snapshot.documentChanges.forEach { change in
for document in snapshot.documents{
let data = document.data()
let id = ("\(doc)-\(document.documentID)")
let review = data["review"] as? String ?? ""
let likes = data["likes"] as? Int ?? 0
// I thought swiftui Identifiables would be smart enough to not add another identifiable if there is already an existing one with the same id, but I was wrong, this just duplicates the rating
// self.allRatings.append(Rating(id: id, review: review, likes: likes))
// This is my current solution, to overwrite the Rating in the allRatings array, however I can not figure out how to get the index of the changed rating
// "0" should be replaced with whatever Rating index is being changed
self.allRatings[0] = Rating(id: id, review: review, likes: likes)
}
}
}
}
}
我想要的只是让每个评分的“点赞”实时显示，并在有人喜欢评分时更新。这看起来很简单，但我对 swiftui 比较陌生，所以我可能完全不知道我是如何做到这一点的。非常感谢任何帮助！
【问题讨论】：
-
将 ObservableObject 和 @Published 添加到 Rating 及其属性。这样，当 Rating 更新其已发布属性之一时，视图将自动重绘。
-
@Helperbug 感谢您的快速回复！我不认为我完全理解你的建议。您是否建议我将“struct Rating: Identifiable”移动到我的 FeedViewModel Observable 对象类中？如果是这样，我将如何覆盖我的 allRatings 数组中的评分之一？
-
Rating 必须是具有已发布属性的可观察值。当评级的属性更新时，它将发布更改，并且视图将知道自己更新。尝试将评级等级更改为：class Rating: ObservableObject, Identifiable { var id: String @Published var review: String Published var likes: Int }
-
当我真的觉得这会奏效哈哈遗憾的是我收到以下错误：“参数传递给不带参数的调用删除'（id：id，review：review，likes：likes )'" 每当我尝试运行任何尝试写入/推送到可识别评级的函数时。
标签： swift firebase google-cloud-firestore swiftui identifiable