我正在努力为我的登录屏幕设计正确的设置。我想我需要将其更改为从视图模型调用的asynctask，但不确定这是否是正确的方法。当前代码将结果对象传回视图模型，但由于异步网络请求，它传回一个空对象。最好的方法是什么？
我的代码是这样的：
视图模型：

public void login(String username, String password) {
    // can be launched in a separate asynchronous job
    Result<LoggedInUser> result = loginRepository.login(username, password);

    if (result instanceof Result.Success) {
        LoggedInUser data = ((Result.Success<LoggedInUser>) result).getData();
        loginResult.setValue(new LoginResult(new LoggedInUserView(data.getEmail(),data.getOrganisation(),data.getFirstname(),data.getLastname(),data.getOrganisationshort())));
    } else {
        loginResult.setValue(new LoginResult(R.string.login_failed));
    }
}

存储库：

public Result<LoggedInUser> login(String username, String password) {
            Result<LoggedInUser> result = dataSource.login(username, password);
            if (result instanceof Result.Success) {
                setLoggedInUser(((Result.Success<LoggedInUser>) result).getData());
            }
            return result;
        }

数据源：

public Result<LoggedInUser> login(String username, String password) {
        Log.d("LOGIN_ATTEMPTS", "Connecting...");
        final LoggedInUser[] data = new LoggedInUser[1];
        try {
            LoggedOutUser loggedOutUser = new LoggedOutUser(username,password);
            // TODO: handle loggedInUser authentication
            Retrofit retrofit = new Retrofit.Builder().baseUrl("http://192.168.0.239:3622/")
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();
            JsonPlaceHolderApi jsonPlaceHolderApi = retrofit.create(JsonPlaceHolderApi.class);
            Call<LoggedInUser> callAsync = jsonPlaceHolderApi.postAuth(loggedOutUser);    
            callAsync.enqueue(new Callback<LoggedInUser>() {
                @Override
                public void onResponse(Call<LoggedInUser> call, Response<LoggedInUser> response) {
                    if (!response.isSuccessful()) {
                        Log.d("HTTP_CODE","Code " + response.code());
                        try {
                            Log.d("HTTP_ERROR",response.errorBody().string());
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        return;
                    }

                    data[0] = response.body();
                    Log.d("HTTP_DATA", ((LoggedInUser) data[0]).getUserId());
                }

                @Override
                public void onFailure(Call<LoggedInUser> call, Throwable t) {
                    Log.d("HTTP_ERROR", t.getMessage());
                }

            });
            return new Result.Success<>(data[0]);

        } catch (Exception e) {
            e.printStackTrace();
            Log.d("HTTP_ERROR", "Error logging in");
            return new Result.Error(new IOException("Error logging in", e));
        }
    }