Question

这是我的代码：

     func authenticateCredentials(usernameString: String, passwordString: String) -> () -> Bool {
        func isAuthUser() -> Bool {

        client.invokeAPI("AuthenticateAndFetchData",
                         body: nil,
                         httpMethod: "GET",
                         parameters: ["userid": usernameString,"password":passwordString],
                         headers: nil)
        {
            (result, response, error) -> Void in
            if let err = error {
                print("ERROR ", err)

            } else if let res = result {



                    let jsonArray = res as! NSArray
                    for value in jsonArray[0] as! NSDictionary {
                        let jsonstring = value.value as! String
                        NetworkService.jsonResponse = jsonstring
                        if let data = jsonstring.data(using: .utf8) {
                            if let content = try? JSONSerialization.jsonObject(with: data, options: []),
                                let array = content as? [[String: Any]]
                            {
                                for jsondict in array {
                                    let auth = jsondict["IsAuth"]! as! String
                                    self.isAuth = (auth == "true") ? true : false
                                    let substring = NetworkService.parseJSONString(jsonString: jsonstring, key: "Activities")
                                    let substring2 = NetworkService.parseJSONString(jsonString: substring(), key: "activityname")
                                    let activityString = NetworkService.parseJSONvalue(jsonString:substring())
                                }
                            }
                        }
                    }
                }
            }
            return self.isAuth
        }
        return isAuthUser

    }

}

我在登录按钮上调用此功能。但是当我第一次使用正确的凭据按下按钮时，此函数返回false，当我再按一次，然后我执行完成处理程序，它将isAuth更改为true并且函数返回true 。

所以，我必须按两次按钮进行身份验证，我怎样才能让它第一次返回true。我想在函数返回之前等待完成块的执行。

Answer 1

假设您的客户端调用已经是异步并在主队列上调用其完成处理程序，请将完成处理程序作为额外参数添加到您的方法中：

root
 - Users
   - [UserID]
      - UserPosts
        -K_54s1smPPh6qN4znuT
 - Posts
   - -K_54s1smPPh6qN4znuT
     - key1: val
     - key2: val
     - User:
       - -K_54sSomeKeyFromUsersObject: "John Doe"
...

您可以这样称呼它：

func authenticateCredentials(usernameString: String, passwordString: String, completion: @escaping (Bool) -> Void){
    client.invokeAPI("AuthenticateAndFetchData",
                 body: nil,
                 httpMethod: "GET",
                 parameters: ["userid": usernameString,"password":passwordString],
                 headers: nil) {
        ...
        let auth = jsondict["IsAuth"]! as! String
        let isAuth = (auth == "true") ? true : false
        ...
        completion(isAuth)
    }
}

等待此完成处理程序在函数返回值之前完成执行

1 个答案: