Swift 无法转换类型为';()';到预期的参数类型';(()->;无效)';
我遇到这样的问题,有人有什么办法解决吗? Xcode 11.2,SwiftUISwift 无法转换类型为';()';到预期的参数类型';(()->;无效)';,swift,firebase,google-cloud-firestore,swiftui,ios13,Swift,Firebase,Google Cloud Firestore,Swiftui,Ios13,我遇到这样的问题,有人有什么办法解决吗? 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").do
.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))
}
}
}
}
.onAppear
需要一个闭包,所以我认为需要用花括号括起来
.onAppear(perform: { self.sessionChat.loadMsgInChatRoom(chatRoom: chatRoom) } )
或者更简单的方法:
.onAppear {
self.sessionChat.loadMsgInChatRoom(chatRoom: chatRoom)
}