My API call isn't working and my app return me "Expected BEGIN_ARRAY but was BEGIN_OBJECT at path $ solution"

Question

Hi I'm currently working on a android app (android studio) for a class and i need to make API calls i followed some tutorials (android developper and some on YT). From these tutorial i learned to use retrofit2 to make API request but i don't understand why i'm getting this error Expected BEGIN_ARRAY but was BEGIN_OBJECT at path $ solution it seems that i don't receive a Json list but only an object here are what i use to make the calls:

I tried to change my Dataclass for an object but it did not work here is my code for references

this is my ApiService class

private val moshi = Moshi.Builder()
    .add(KotlinJsonAdapterFactory())
    .build()

private val retrofit = Retrofit.Builder()
    .addConverterFactory(MoshiConverterFactory.create(moshi))
    .baseUrl(BASE_URL)
    .build()
interface WebtoonApiService {

    //Fonction qui renvoie le JSON de la page d'accueil, les deux headers son
    // les clé d'accées à l'API et l'adresse de l'host
    @Headers("X-RapidAPI-Key: MyKey", "X-RapidAPI-Host: webtoon.p.rapidapi.com")
    @GET("titles/list?genre=ALL&sortOrder=READ_COUNT&startIndex=0&pageSize=1&language=en")
    suspend fun getHome(): List<Titles>
    @GET("titles/get-info?titleNo=300138&language=en")
    suspend fun getTitle(): String


}
object WebtoonApi {
    val retrofitService : WebtoonApiService by lazy {
        retrofit.create(WebtoonApiService::class.java) }
}

my data class

package com.example.myapplication.network

import com.squareup.moshi.Json
data class  Titles (
    val message: List<String>,
    val type: String,
    val service: String,
    val result: List<String>
)

the viewmodel that make the API call

class HomeViewModel : ViewModel(){

    init {
            getHome()
        }
    val _status = MutableLiveData<String>()
    val status: LiveData<String> = _status


    private fun getHome(){
        viewModelScope.launch {
            try{
             val currentText = WebtoonApi.retrofitService.getHome()
                Log.d("TEST",currentText.toString())
            _status.value = "Success: $currentText"
            }
        catch (e: Exception){
            _status.value = "Failure: ${e.message}"
            }
        }
    }
}

the Json i get from my GET

{
  "message": {
    "type": "response",
    "service": "com.naver.webtoon",
    "version": "0.0.1",
    "result": {
      "titleInfo": {
        "titleNo": 300138,
        "language": "en",
        "writingAuthorName": "s0s2",
        "writingCommunityAuthorId": "o6ocb",
        "representGenre": "COMEDY",
        "genreInfo": {
          "name": "Comedy",
          "mask": "https://webtoons-static.pstatic.net/image/genre/challenge_new_mask/mask_and_comedy.png",
          "index": 0,
          "color": "EEA800",
          "code": "COMEDY"
        },
        "title": "The Little Trashmaid",
        "synopsis": "Short comic strips of a mermaid in the modern days~\n\nUpdates every two weeks (on friday)\n\n\nTwitter: @s0s2\nTumblr: s0s2\nInstagram: s0s2tagram\nYoutube: s0s2",
        "serviceStatus": "SERVICE",
        "thumbnail": "/20210512_221/1620803524068sbgtd_JPEG/7b9a0504-bebd-4795-92db-5aa0d8659677.jpg",
        "starScoreAverage": 9.79,
        "readCount": 213553057,
        "favoriteCount": 1481152,
        "totalServiceEpisodeCount": 131,
        "lastEpisodeRegisterYmdt": 1697824801000,
        "linkUrl": "https://www.webtoons.com/en/canvas/the-little-trashmaid/list?title_no=300138",
        "firstEpisodeNo": 1,
        "genreColor": "EEA800",
        "badgeType": "FAVORITE",
        "likeitCount": 14929324,
        "ageGradeNotice": false,
        "rewardAdExposureDays": 14,
        "previewDisabled": false
      },
      "challengeAuthorPatreon": {
        "userId": "21805004",
        "userName": "thelittletrashmaid",
        "patronUrl": "https://www.patreon.com/bePatron?utm_source=webtoons&utm_medium=link&utm_campaign=thelittletrashmaid&u=21805004&redirect_uri=http%3A%2F%2Fm.webtoons.com%2Fapp%2Fchallenge%2FpatreonCallback%3FpageType%3DepisodeList%26title_no%3D300138",
        "usePatronage": true
      }
    }
  }
}

my error message the retuen statment is on failure of course

I already searched solution all night long (it's my first question here i tried my best to make it clear, sorry if it's not, english isn't my main language)

Answer 1

Seems like your type of response in WebtoonApiService.getHome and your Titles data class don't match the actual response from the service. You need to return a single Titles object, not List from WebtoonApiService.getHome method.

Also the set of fields in Titles class should match the fields in json. For example, the field "message" should reference another data class (i.e. data class Message), not "List". That new data class should contain String fields "type" and "service" and another field "result" of type i.e. Result (not List).