如何在其他viewController中使用变量？ -迅捷

Question

我创建了LoginService类，以使用POST方法从Web服务获取数据，并在UIViewController调用该类。 它有效，但是我想在另一个ViewController显示变量loginObj.fullname值。 我尝试了很多方法，但是我得到的输出是一个空字符串。 我该怎么办？ 这是我的LoginService类代码：

func callService(_ urlString: String, callback: @escaping(_ LoginArray:[LoginModel]) -> Void, username:String, password:String)
{
    let url = URL(string: urlString);
    var request = URLRequest(url: url!);
    request.httpMethod = "POST";
    let postString = "username=" + username + "&password=" + password;
    request.httpBody = postString.data(using: .utf8);
    let sessionConfig = URLSessionConfiguration.ephemeral;
    let session = URLSession(configuration: sessionConfig);
    let task = session.dataTask(with: request)
    {
        (data:Data?, URLResponse:URLResponse?, error:Error?) in
        if error != nil
        {
            print("\n\n\n\n\n\(error?.localizedDescription)\n\n\n\n\n");
        }
        else
        {
            if let returnData = data
            {
                do
                {
                    var valSucceeded = false;
                    var valResponseCode = "";
                    var valResponseDescription = "";
                    var valFullname = "";
                    var valToken = "";
                    var LoginArray = [LoginModel]();

                    print("\n\n\n\n\n");
                    if let jsonObject = try JSONSerialization.jsonObject(with: returnData, options: .allowFragments) as? [String: AnyObject]
                    {
                        valSucceeded = (jsonObject["succeeded"] as? Bool)!;
                        valResponseCode = (jsonObject["responseCode"] as? String)!;
                        valResponseDescription = (jsonObject["responseDescription"] as? String)!;
                        valFullname = (jsonObject["fullname"] as? String)!;
                        valToken = (jsonObject["token"] as? String)!;

                        let entryResult = LoginModel(succeeded: valSucceeded, responseCode: valResponseCode, responseDescription: valResponseDescription, fullname: valFullname, token: valToken);
                        LoginArray.append(entryResult);
                    }

                    DispatchQueue.main.async(execute: {
                        callback(LoginArray);
                    });
                    print("\n\n\n\n\n");
                }
                catch
                {
                    print("\n\n\n\n\n JSON Serialization Error \n\n\n\n\n");
                }
            }
            else
            {
                print("\n\n\n\n\n Call API Error \n\n\n\n\n");
            }
        }
    }
    task.resume();
}

这是我的ViewController代码：

@IBAction func loginClick(_ sender: AnyObject) {
    let input_username = username.text;
    let input_password = password.text;

    if ReachAbility.isConnectedToNetwork() == true
    {
        let service = LoginServices();
        service.callService("http://www........", callback: callServiceFinished, username: input_username!, password: input_password!);
    }
    else
    {
        let failedStatus = "ไม่สามารถเชื่อมต่ออินเทอร์เนตได้";

        let alert = UIAlertController(title: failedStatus, message: "กรุณาตรวจสอบการเชื่อมต่อ", preferredStyle: .alert);
        let msgAlert = UIAlertAction(title: "ตกลง", style: .cancel, handler: nil);
        alert.addAction(msgAlert);
        present(alert, animated: true, completion: nil);
    }
        }

func callServiceFinished(_ LoginArray:[LoginModel]) {

    print("\n\n\n\n\n");
    for loginObj in LoginArray
    {
        print("\(loginObj.succeeded)\n");
        print("\(loginObj.responseCode)\n");
        print("\(loginObj.responseDescription)\n");
        print("\(loginObj.fullname)\n");
        print("\(loginObj.token)");
        print("\n\n");

        if (loginObj.succeeded != true)
        {
            let alert = UIAlertController(title: nil, message: loginObj.responseDescription, preferredStyle: .alert);
            let msgAlert = UIAlertAction(title: "OK", style: .cancel, handler: nil);
            alert.addAction(msgAlert);
            present(alert, animated: true, completion: nil);

        }
        else
        {
            print("Error!")
        }
    }
    print("\n\n\n\n\n");
}

Answer 1

您可以像这样与单例共享您的实例：

class LoginObject {
    public static var shared = LoginObject()
}
// In VC
let fullname = LoginObject.shared.fullname

您也可以使用Segue方法将对象发送到另一个VC。 但由于您必须在每次转换时发送数据，因此不建议使用它。