ios - 如何在 swift 3 的其他功能中使用服务器响应和数据

Question

正在向服务器发出发布请求，服务器会响应一些数据，正在将收到的数据存储在名为 json 的变量中，现在正在尝试从其他函数访问此变量，但出现错误:“使用未解析的标识符“json”
这是代码，以防您需要它

    @IBAction func Login(_ sender: UIButton) {
    guard let url = URL(string: "url was here..lol") else {return}
    var request = URLRequest(url: url)
    request.httpMethod = "POST"
    let postString = "data to be posted"
    print(postString)
    request.httpBody = postString.data(using: .utf8)
    let task = URLSession.shared.dataTask(with: request) { data, response, error in
    if let response = response {
    print(response)
    }
       if let data = data {
            do {
                let json = try? JSONSerialization.jsonObject(with: data, options: []) as! [String: Any]
                let token = json?["access_token"] as! String
                print (json)

        }
        }
        }
    task.resume()

}

Answer 1

您需要在类级别上声明要在函数之间共享的变量，以便类中的每个函数都可以访问它们。 token 是具有此实现的类的实例属性，因此每个类实例都有自己的名为 token 的变量，可以在类内的任何位置访问该变量。

class MyViewController: UIViewController {
    var token = ""

    @IBAction func Login(_ sender: UIButton) {
        guard let url = URL(string: "url was here..lol") else {return}
        var request = URLRequest(url: url)
        request.httpMethod = "POST"
        let postString = "data to be posted"
        print(postString)
        request.httpBody = postString.data(using: .utf8)
        let task = URLSession.shared.dataTask(with: request) { data, response, error in
            if let response = response {
                print(response)
            }
            if let data = data {
                guard let json = (try? JSONSerialization.jsonObject(with: data, options: [])) as? [String: Any] else {return}
                guard let receivedToken = json["access_token"] as? String else {return}
                self.token = receivedToken
                otherFunction()
            }
        }
    task.resume()
    }

    func otherFunction(){
        print(token)
    }
}