如何使异步请求Swift 5的for循环停止

Question

这是我希望for循环等待func getVenueDetails完成的func，如果完成为true，则退出循环，如果不继续下一个场地id。

func searchVenues(lat: Double, lng: Double) {
let parameter: [String: String] = [
"ll": "(lat),(lng)",
"radius": "600",
"limit": "10",
"intent": "browse",
"categoryId": "4bf58dd8d48988d1e4931735,4bf58dd8d48988d1f1931735,4deefb944765f83613cdba6e,4bf58dd8d48988d17f941735,52e81612bcbc57f1066b79eb,4bf58dd8d48988d181941735,4bf58dd8d48988d1f4931735,4bf58dd8d48988d189941735,4bf58dd8d48988d182941735,4bf58dd8d48988d17b941735,4bf58dd8d48988d163941735,4bf58dd8d48988d164941735,4bf58dd8d48988d165941735,56aa371be4b08b9a8d57356a,4bf58dd8d48988d12f941735"
];
var isSent2: Bool = false

client.request(path: "venues/search", parameter: parameter) { result in
switch result {
case let .success(data):
let jsonResponse = try! JSONSerialization.jsonObject(with: data, options: [])
let json = JSON(jsonResponse)
let name = json["response"]["venues"][0]["name"].string
print("NAME FROM JSON: ", name)
let id = json["response"]["venues"][0]["id"].string
print("id of foursquare", id)
let group = DispatchGroup()
group.notify(queue: .main) {

for (key,subJson):(String, JSON) in json["response"]["venues"] {
//group.enter()
let placeName = subJson["name"].string
print("place name:",placeName.unsafelyUnwrapped)
let placeId = subJson["id"].string
print("place id:",placeId.unsafelyUnwrapped)
group.enter()
self.getVenueDetails(id: placeId!) { (isSent) in
print("isSent", isSent)
isSent2 = isSent
group.leave()
}
if (isSent2){
print("linaaa")
//group.leave()
break
}
}//end of for loop
}
//  print("json == ", jsonResponse)
case let .failure(error):
// Error handling
switch error {
case let .connectionError(connectionError):
print(connectionError)
case let .responseParseError(responseParseError):
print(responseParseError)   // e.g. JSON text did not start with array or object and option to allow fragments not set.
case let .apiError(apiError):
print(apiError.errorType)   // e.g. endpoint_error
print(apiError.errorDetail) // e.g. The requested path does not exist.
}
}
}
}

这是另一个函数，用于请求场地详细信息，所以我希望当isSent返回true时，searchVenues中的for循环停止(中断(，如果返回false，则继续下一个循环。

func getVenueDetails(id: String, completionHandler: @escaping (Bool)->Void) {
var isSent: Bool = false

let parameter: [String: String] = [
"VENUE_ID": "(id)",
];
client.request(path: "venues/(id)", parameter: parameter) { result in
switch result {
case let .success(data):
let jsonResponse = try! JSONSerialization.jsonObject(with: data, options: [])
let json = JSON(jsonResponse)
// print("json == ", jsonResponse)
let name = json["response"]["venue"]["name"].string
if let rating:Double = json["response"]["venue"]["rating"].double {
print("rating from: ", rating)
//rat = rating
if (rating > 2)  {
self.foursquareNotification(name: name!)
print("here inside lol")
isSent = true
DispatchQueue.main.async {

completionHandler(isSent)
print("isSent hereee", isSent)
}
} //end if
else {
isSent = false
DispatchQueue.main.async {

completionHandler(isSent)
}
}//end else
} //end if rating
//                rat = json["response"]["venue"]["rating"].double!
//                print("rating from: ", rat)
//                //rat = rating.unsafelyUnwrapped
case let .failure(error):
// Error handling
switch error {
case let .connectionError(connectionError):
print(connectionError)
case let .responseParseError(responseParseError):
print(responseParseError)   // e.g. JSON text did not start with array or object and option to allow fragments not set.
case let .apiError(apiError):
print(apiError.errorType)   // e.g. endpoint_error
print(apiError.errorDetail) // e.g. The requested path does not exist.
}
}
}
//return isSent
}//end getVenueDetails

Answer 1

您需要删除for循环

var res =  json["response"]["venues"] 

然后

var current = 0
func start(item:ItemType) {
let placeName = subJson["name"].string 
let placeId = subJson["id"].string
self.getVenueDetails(id: placeId!) { (isSent) in 
if isSent {
counter += 1
start(nextItem)
}
}