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How to Parse Json in Kotlin Using Retrofit?

i am new to kotlin and i am in learning phase. I have followed many links but didn't able to understand completely.
I want Json response to show in my textview.
Problem: 1
I have tried this code but was unable to get data, but i want to get the items inside data object. Quote and author are coming null.
{
"status": 200,
"message": "Success",
"data": {
"Quote": "The pain you feel today will be the strength you feel tomorrow.",
"Author": ""
},
"time": "0.14 s"
}
Problem: 2
I dont know how to parse this response in textview
object ServiceBuilder {
private val client = OkHttpClient.Builder().build()
private val retrofit = Retrofit.Builder()
.baseUrl("https://url.com.pk/") // change this IP for testing by your actual machine IP
.addConverterFactory(GsonConverterFactory.create())
.client(client)
.build()
fun<T> buildService(service: Class<T>): T{
return retrofit.create(service)
}}
RestApi
interface RestApi{
#Headers("Content-Type: application/json")
#POST("api/getquotes")
abstract fun addUser(#Body userData: UserInfo): Call<UserInfo>}
RestAPiService
class RestApiService
{
fun addUser(userData: UserInfo, onResult: (UserInfo?) -> Unit)
{
val retrofit = ServiceBuilder.buildService(RestApi::class.java)
retrofit.addUser(userData).enqueue(
object : Callback<UserInfo>
{
override fun onFailure(call: Call<UserInfo>, t: Throwable)
{
onResult(null)
}
override fun onResponse( call: Call<UserInfo>, response: Response<UserInfo>)
{
val addedUser = response.body()
Log.d("responsee",""+addedUser)
onResult(addedUser)
}
}
)
}
}
UserInfo
data class UserInfo (
#SerializedName("Quote")
val quote : String,
#SerializedName("Author")
val author : String
)
MainActivity
fun getQuotes() {
val apiService = RestApiService()
val userInfo = UserInfo("","")
apiService.addUser(userInfo) {
Log.d("Error registering user","errter")
/*if ( != null)
{
// it = newly added user parsed as response
// it?.id = newly added user ID
} else {
Log.d("Error registering user","errter")
}*/
}
}
Any help would be appreciated :)

Status, message and data are all part of the response so you need to take care of that. For example this
data class AddUserResponse(
val `data`: UserInfo, //like you defined it
val message: String,
val status: Int,
val time: String
)
This means parameter and response are different so the RestApi needs to be changed to this
abstract fun addUser(#Body userData: UserInfo): Call<AddUserResponse>}
This in turn also change the types in the service like
class RestApiService
{
fun addUser(userData: UserInfo, onResult: (UserInfo?) -> Unit)
{
val retrofit = ServiceBuilder.buildService(RestApi::class.java)
retrofit.addUser(userData).enqueue(
object : Callback<AddUserResponse>
{
override fun onFailure(call: Call<AddUserResponse>, t: Throwable)
{
onResult(null)
}
override fun onResponse( call: Call<AddUserResponse>, response: Response<AddUserResponse>)
{
val addedUser = response.body()
Log.d("responsee",""+addedUser)
onResult(addedUser.data)
}
}
)
}
}
now in getQuotes you will have that it is a UserInfo object
apiService.addUser(userInfo) {
val returnedUserInfo = it
}

just follow my steps :
File->settings->Plugins
search for JSON To Kotlin class and install it
again click on File->New->Kotlin Data class from JSON
paste your json code here and click on generate. It will generate POJO classes and you will good to go.

The first thing I noticed, is that the data in your json is:
"Quote": "The pain you feel today will be the strength you feel tomorrow.",
"Author": ""
While your UserInfo defined #SerializedName("message") for Quote.

How to parse response with retrofit2 Kotlin

I'm stuck with parsing the response. In Swift I can make a codable to help parsing the json response. I'm new to Kotlin and I'm working on someone else existing project. I made a data class for string and boolean but I don't know the syntax to parse it. Please help and thank you.
The responseBody json
{
"bearerToken": "########",
"staySignIn": false
}
//Interface
interface PostInterface {
class User(
val email: String,
val password: String
)
#POST("signIn")
fun signIn(#Body user: User): Call<ResponseBody>
//Network handler
fun signIn(email: String, password: String): MutableLiveData<Resource> {
val status: MutableLiveData<Resource> = MutableLiveData()
status.value = Resource.loading(null)
val retrofit = ServiceBuilder.buildService(PostInterface::class.java)
retrofit.signIn(PostInterface.User(email, password)).enqueue(object : Callback<ResponseBody> {
override fun onFailure(call: Call<ResponseBody>, t: Throwable) {
errorMessage(status)
}
override fun onResponse(call: Call<ResponseBody>, response: Response<ResponseBody>) {
if (response.code() == 200) {
try {
status.value = //how to parse using the model??
} catch (ex: Exception) {
parseError(400, response.body().toString(), status)
}
} else {
//do something...
}
}
})
return status
}
//Model
data class SignInModel(
#field:SerializedName("bearerToken")
val bearerToken: String? = null,
#field:SerializedName("staySignIn")
val staySignIn: Boolean? = null
)
//Storing value class
class RrefManager constructor(var applicationContext: Context) {
private fun getSharedPrefEditor(): sharedPrefEditor.Editor {
return applicationContext.getSharedPrefEditor(prefStorageName, Context.MODE_PRIVATE).edit()
}
public fun setBearerToken(token: String) {
getSharedPrefEditor().putString("bearerToken", token).apply()
}
public fun setStaySignIn(enabled: Boolean) {
getSharedPrefEditor().putBoolean("staySignIn", enabled).apply()
}
}
//SignIn Button
viewModel.signIn().observe(viewLifecycleOwner, androidx.lifecycle.Observer { v ->
if (v.status == Resource.Status.SUCCESS) {
val model = v.data as SignInModel
pref.setToken(model.token as String) //storing value
pref.setTwoFactorEnabled(model.twoFactorEnabled as Boolean) //storing value
} else if (v.status == Resource.Status.ERROR) {
//do something...
}
})

I think your best option to achieve something like the codable in swift is to use Gson library for parsing api responses.
When you create the retrofit instance you pass the gson converter to the builder like:
val retrofit = Retrofit.Builder()
.baseUrl(BaseUrl)
.addConverterFactory(GsonConverterFactory.create())
.build()
After you have done that you can make the api return the response you have as the data class, like:
//Interface
interface PostInterface {
#POST("signIn")
fun signIn(#Body user: User): Call<SignInModel>
}
To read the answer from the callback on your class, the response inside the network call is already parsed into your model in the callback. All the retrofit callback should be changed to receive Callback and then you can access directly like status.value = response.body()
For more info you can consult the retrofit library page where it gives all the details and explanations on how to use it correctly.
https://square.github.io/retrofit/

Retrofit Kotlin unable to create a working post request

I'm trying to do a POST request using Retrofit but I'm unable to make it work. It does work on Postman. I specified the header "Content-Type: application/json" and set my "email" and "password" parameters in the body and it works well.
But it doesn't on Android. Here are my codes :
private fun login() {
val user = User("test#gmail.com", "dsea2EcFI32\\\"af'xn")
this.service.login(user).enqueue(object : Callback<LoginResponse> {
override fun onResponse(call: Call<LoginResponse>, response: Response<LoginResponse>) {
if (response.code() == 200) {
// TODO
}
}
override fun onFailure(call: Call<LoginResponse>, t: Throwable) {
// TODO
println(t.message)
}
})
}
The request :
#Headers("Content-Type: application/json")
#POST("/api/authentication/login")
fun login(#Body body: User): Call<LoginResponse>
User model
data class User(val email: String, val password: String)
LoginResponse :
class LoginResponse {
#SerializedName("user")
val user : UserResponse? = null
}
class UserResponse {
#SerializedName("id") val still : String = null
#SerializedName("firstName") val running : String = null
#SerializedName("lastName") val bicycle : String = null
#SerializedName("email") val walking : String = null
#SerializedName("token") val vehicle : String = null
}
In case the auth is a failure, the server sends me back an HTML page so the only error I have is
Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 1 path $
I already set it to true and it keeps saying me that the GSON parsed object isn't a JSON object but I know there's an Android code here
Can someone helps me finding it ?
PS : I even tried to send the body as a JSON object but same error
PS2 : might this be due to the password even If I added enough backspace to accept the special characters ? the real string is dsea2EcFI32"af'xn
EDIT :
As asked, here is my retrofit builder with the HTTPInterceptor
val client = OkHttpClient()
val interceptor = HttpLoggingInterceptor()
interceptor.level = HttpLoggingInterceptor.Level.BODY
client.interceptors().add(interceptor)
val retrofit = Retrofit.Builder()
.baseUrl(BuildConfig.API_URL)
.addConverterFactory(GsonConverterFactory.create())
.client(client)
.build()
this.service = retrofit.create(LoginResponse::class.java)

I found the solution.
The issue was the password because it had backslashes and quotes inside of it.
Kotlin was doing a wrong parsing.

Convert your fun login object like below one.
#Headers("Content-Type: application/json")
#POST("/api/authentication/login")
fun login(#Body requestBody: RequestBody): Call<LoginResponse>
then create a fun like this
fun makeGSONRequestBody(jsonObject: Any?): RequestBody {
return RequestBody.create(MediaType.parse("multipart/form-data"), Gson().toJson(jsonObject))
}
you need to pass your User object like below
private fun login() {
val user = User("test#gmail.com", "dsea2EcFI32\\\"af'xn")
this.service.login(makeGSONRequestBody(user)).enqueue(object : Callback<LoginResponse> {
override fun onResponse(call: Call<LoginResponse>, response: Response<LoginResponse>) {
if (response.code() == 200) {
// TODO
}
}
override fun onFailure(call: Call<LoginResponse>, t: Throwable) {
// TODO
println(t.message)
}
})
}

How to fix retrofit errorjava.lang.IllegalStateException android

I have parse the data from this link
https://api.androidhive.info/contacts/
But I am getting error as
E/on Failure :: retrofit errorjava.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
Below is the code which I done.
class RetrofitService {
val liveUserResponse:MutableLiveData<List<ContactBase>> = MutableLiveData()
companion object Factory {
var gson = GsonBuilder().setLenient().create()
fun create(): ApiInterface {
Log.e("retrofit","create")
val retrofit = Retrofit.Builder()
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.addConverterFactory(GsonConverterFactory.create(gson))
.baseUrl("https://api.androidhive.info/")
.build()
return retrofit.create(ApiInterface::class.java)
}
}
fun loadContactsData(): MutableLiveData<List<ContactBase>>? {
Log.e("loadAndroidData","yes")
val retrofitCall = create().getContacts()
retrofitCall.enqueue(object : Callback<List<ContactBase>> {
override fun onFailure(call: Call<List<ContactBase>>, t: Throwable?) {
Log.e("on Failure :", "retrofit error"+t)
Log.e("on Failure :", "retrofit error"+call)
}
override fun onResponse(call: Call<List<ContactBase>>, response: retrofit2.Response<List<ContactBase>>) {
val list = response.body()
for (i in list.orEmpty()){
Log.e("on response 1:", ""+i)
}
liveUserResponse.value = list
Log.e("hasActiveObservers 1", liveUserResponse.hasActiveObservers().toString()+" check")
Log.e("on response 2 :", liveUserResponse.toString()+" check")
}
})
return liveUserResponse
}
}
But it's always going to Failure state.
data class ContactBase (val contacts : List<Contacts>)
data class Contacts (
val id : String,
val name : String,
val email : String,
val address : String,
val gender : String,
val phone : Phone
)
data class Phone (
val mobile : String,
val home : String,
val office : String
)
interface ApiInterface{
#GET("contacts/")
fun getContacts(): Call<List<ContactBase>>
}
class AndroidViewModel:ViewModel(){
private val retrofitService = RetrofitService()
fun getContactsData(): MutableLiveData<List<ContactBase>>?{
return retrofitService.loadContactsData()
}
}
I cross verified the url too and pojo class. But it always go to failure case in retrofit.

The error says that the incomming JSON starts with a { and not with a [ which means it's an object and not an array of objects.
So you should be having a class that has an array of Contact in order to make that call successful.
A small heads up: Since you are using GSON, your model classes would need the implementation of #SerializedName(string) annotation above the variables.

Retrofit 2 request always failure - Kotlin

I tried to learn about kotlin and retrofit 2 at the same time. I have this code.
I want to take all the /posts from this. But its always return a failure code. I'm very new in this, thanks
Network interface
interface APIService {
#GET("/posts")
fun getPosts(): Call<List<UserData>>
POJO class
open class UserData {
#SerializedName("userId")
#Expose
open var user_id: Int? = null
#SerializedName("id")
#Expose
open var id: Int? = null
#SerializedName("title")
#Expose
open var title: String? = null
#SerializedName("body")
#Expose
open var body: String? = null
}
MainActivity
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val retrofit = Retrofit.Builder()
.addConverterFactory(GsonConverterFactory.create())
.baseUrl("https://jsonplaceholder.typicode.com/")
.build()
val service = retrofit.create(APIService::class.java)
service.getPosts().enqueue(object : Callback<List<UserData>> {
override fun onFailure(call: Call<List<UserData>>?, t: Throwable?) {
Log.d("RetrofitTest", t.toString())
}
override fun onResponse(call: Call<List<UserData>>?, response: Response<List<UserData>>?) {
Log.d("RetrofitTest", "onFailure")
}
})
}
}

in APIService interface #GET("posts") insted of #GET("/posts")

It always failed because the reason is the invalid URL. The mistake you have done is '/'. Either you can put the slash('/') in the base URL or at the starting of the Endpoint. In your case, the URL is like "https://jsonplaceholder.typicode.com//posts". Which is invalid that's why your request getting failed. So just remove the '/' from the Endpoint.
Make request interface like this:
interface APIService {
#GET("posts")
fun getPosts(): Call<List<UserData>>
}