我是新的Android应用程序，我正在做一个项目，我正在用get测试Retrofit，我有错误，它给出了错误非正文HTTP方法不能包含@Body。有很多例子在网站上，我尝试了我的代码，它不工作。

public interface UserService {

    @GET("person/")
    Call<LoginResponse> loginUser(@Body LoginRequest loginRequest);
}

我见过很多这个错误的例子，我试过了，它仍然给出了错误。
我试过的代码：

public interface UserService {

    @GET("person/")
    Call<LoginResponse> loginUser(@Query("username") LoginRequest loginRequest);
}

我的API

public class UserController : ApiController
    {
        public SqlConnection mainconn = new SqlConnection(ConfigurationManager.ConnectionStrings["MyConnection"].ConnectionString);

        [HttpGet]
        public IHttpActionResult GetUsers()
        {
            List<People> list = new List<People>();
            string sqlquery = "Select LoginID, PersonEye, username, password from tblLogin";
            using (SqlCommand com = new SqlCommand(sqlquery, mainconn))
            {
                mainconn.Open();
                SqlDataReader dr = com.ExecuteReader();
                while (dr.Read())
                {
                    list.Add(new People()
                    {
                        LoginID = Convert.ToInt32(dr.GetValue(0)),
                        PersonEye = Convert.ToString(dr.GetValue(1)),
                        username = Convert.ToString(dr.GetValue(2)),
                        password = Convert.ToString(dr.GetValue(3))
                    });
                }
            }
            return Ok(list);
        }

        [HttpGet]
        public IHttpActionResult GetuserName(string username)
        {
            List<People> list = new List<People>();
            using (SqlCommand com = new SqlCommand("Select LoginID, PersonEye, username, password from tblLogin where charindex(@name, username) = 1", mainconn))
            {
                mainconn.Open();
                com.Parameters.Add("@name", SqlDbType.VarChar);
                com.Parameters["@name"].Value = username.ToString();
                using (SqlDataReader dr = com.ExecuteReader())
                {
                    while (dr.Read())
                    {
                        list.Add(new People()
                        {
                            LoginID = Convert.ToInt32(dr.GetValue(0)),
                            PersonEye = Convert.ToString(dr.GetValue(1)),
                            username = Convert.ToString(dr.GetValue(2)),
                            password = Convert.ToString(dr.GetValue(3))
                        });
                    }
                }
                return Ok(list);
            }
        }

主要活动：

public void loginUser(LoginRequest loginRequest) {
        Call<LoginResponse> loginResponseCall = ApiClient.getService().loginUser(); //<- here have error after change
        loginResponseCall.enqueue(new Callback<LoginResponse>() {
            @Override
            public void onResponse(Call<LoginResponse> call, Response<LoginResponse> response) {
                if(response.isSuccessful()) {
                    LoginResponse loginResponse = response.body();
                    startActivity(new Intent(MainActivity.this, Visitor.class).putExtra("data",loginResponse));
                    finish();
                } else {
                    String message = "An error occurred please try again later... ";
                    Toast.makeText(MainActivity.this, message, Toast.LENGTH_LONG).show();
                }
            }

            @Override
            public void onFailure(Call<LoginResponse> call, Throwable t) {
                String message = t.getLocalizedMessage();
                Toast.makeText(MainActivity.this, message, Toast.LENGTH_LONG).show();
            }
        });