我遇到了这样的问题，有人知道如何解决吗？ Xcode 11.2，SwiftUI
.onAppear(perform: self.sessionChat.loadMsgInChatRoom(chatRoom: chatRoom)) //then an error
func loadMsgInChatRoom(chatRoom: String) {
let db = Firestore.firestore()
db.collection("chatRoom").document(chatRoom).collection("msg")
.addsnapshotListener { (querysnapshot,err) in
if err != nil {
print((err?.localizedDescription)!)
return
}
for i in querysnapshot!.documentChanges {
if i.type == .added {
let user = i.document.get("user") as! String
let msg = i.document.get("msg") as! String
let idUser = i.document.get("idUser") as! String
let dateMsg = i.document.get("dateMsg") as! String
let id = i.document.documentID
self.msgs.append(dataMessges(id: id,user: user,msg: msg,idUser: idUser,dateMsg: dateMsg))
}
}
}
}