问题描述
我已经简化了我的代码，所以更容易看到我想要做什么，我正在构建一个评级提要，这些评级来自我“关注”的任何人的 firebase 文档
我想要做的就是每当 firebase 说我的评论有新更新时，更改可识别的，因为不得不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)")
}
}
}
}
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,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,likes: likes)
}
}
}
}
}
我想要的只是让每个评分的“喜欢”实时显示，并在有人喜欢某个评分时更新。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怎么做的。非常感谢任何帮助！
解决方法
经过一周的尝试，我终于明白了，希望这对某人有所帮助，如果您想覆盖数组中可识别的内容，请使用您的 id 查找索引。就我而言，我的 ID 是 firebaseCollectionID + firebaseDocumentID，因此这使它始终 100% 唯一，并且允许我从快照侦听器中引用它...
let index = self.allRatings.firstIndex { (Rating) -> Bool in
Rating.id == id
}
然后通过执行以下操作覆盖它：
self.allRatings[index!] = Rating(id: id,review: review,likes: likes)