Retrofit POST - Expected BEGIN_OBJECT but was STRING at line 1 column 2 path $

Question

I am trying to learn retrofit, though it was fairly easy to retrieve texts from the database. I am kinda having trouble when submitting data to the database.

The data I am submitting goes to the database but it shows this error everytime I submit the data.The toast says - Expected BEGIN_OBJECT but was STRING at line 1 column 2 path $

This is my RegisterAPI activity:

public interface RegisterAPI {

@FormUrlEncoded
@POST("/insertText.php")
Call<Result> createUser(
        @Field("name") String name,
        @Field("age") String age);
}

This is my Person class:

public class Person {

@SerializedName("name")
private String name;
@SerializedName("age")
private String age;


public Person(String name, String age) {
    this.name = name;
    this.age = age;
}

public String getName() {
    return name;
}

public String getAge() {
    return age;
}

} 

This is my insertActivity:

 public static String ROOT_URL = "https://MYURL/";

public void insertUser(){

    String name = editTextName.getText().toString().trim();
    String age = editTextAge.getText().toString().trim();

    Gson gson = new GsonBuilder()
            .setLenient()
            .create();

    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(ROOT_URL)
            .addConverterFactory(GsonConverterFactory.create(gson))
            .build();

    RegisterAPI api = retrofit.create(RegisterAPI.class);

    Person user = new Person(name, age);

    Call<Person> call = api.createUser(user.getName(),user.getAge());

    call.enqueue(new Callback<Person>() {
        @Override
        public void onResponse(Call<Person> call, Response<Person> response) {
            Toast.makeText(insertActivity.this, "SUCCESS", Toast.LENGTH_SHORT).show();
        }
        @Override
        public void onFailure(Call<Person> call, Throwable t) {
            Toast.makeText(insertActivity.this, t.getMessage(), Toast.LENGTH_LONG).show();
        }
    });

}

RetrieveText

[{"name":"Gionne","age":"12"},
{"name":"Harley","age":"25"},
{"name":"Gamboa","age":"30"},
{"name":"Lapuz","age":"35"}]

ANSWER TO QUESTION BELOW

Well I want to answer my own question but I am unable to answer it below cause I was marked as DUPLICATE. Anyways the issue were two things, my PHP insertText.php file and my Objects class.

This is my insertText.php file:

<?php 

require_once('dbConnect.php');

    $name = $_POST['name'];
    $age = $_POST['age'];

    $sql = "INSERT INTO javaScriptTesting 
    (name,age) 
    VALUES 
    ('$name','$age')";


 if(mysqli_query($con,$sql)) {
   //ADDED THIS LINE
   $response["message"] = "DATA INSERTED";

   echo json_encode($response);
 } else {
  //ADDED THIS LINE
   $response["message"] = "UNSUCCESSFUL";

   echo json_encode($response);
 }

  mysqli_close($con);

and then this is my Objects class:

public class Person {

@SerializedName("name")
private String name;
@SerializedName("age")
private String age;

  //ADDED THIS LINE
private String message;

public Person(String name, String age) {
    this.name = name;
    this.age = age;
}

public String getName() {
    return name;
}

public String getAge() {
    return age;
}

//ADDED THIS LINE
public String getMessage() {
    return message;
}

Answer 1

In retrofit 2.0 to perform POST request like above, you should use RequestBody type for your parameter like this.

@Multipart
@POST("XXXX")
Call<PlanResponse> myPlans(@Part(Constants.ACTION_ID) RequestBody actionId, @Part(Constants.OFFER_CODE) RequestBody offerCode);

And here how to get requestBody from String.

String somevalue = "somevalue";
RequestBody body = RequestBody.create(MediaType.parse("text/plain"), somevalue);