api implementation through kotlin

•  sync with gradle these files

implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
implementation("com.squareup.okhttp3:logging-interceptor:4.9.1")
implementation 'com.google.code.gson:gson:2.9.0'

• create Retrofit class

package com.example.using_kotlin_api_integretion

import com.google.gson.GsonBuilder
import okhttp3.OkHttpClient
import okhttp3.logging.HttpLoggingInterceptor
import retrofit2.Retrofit
import retrofit2.converter.gson.GsonConverterFactory
import java.util.concurrent.TimeUnit

class RetrofitClass {
    private var retrofit: Retrofit? = null
    private val BASEURL = "https://jsonplaceholder.typicode.com/"


    fun getRetrofit(): Retrofit? {
        val interceptor = HttpLoggingInterceptor()
        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY)
        val apiClient: OkHttpClient = OkHttpClient.Builder()
            .addInterceptor(interceptor)
            .readTimeout(8000, TimeUnit.SECONDS)
            .writeTimeout(8000, TimeUnit.SECONDS)
            .connectTimeout(
                8000, TimeUnit.SECONDS
            )
            .retryOnConnectionFailure(false)
            .build()
        val gson = GsonBuilder()
            .setLenient()
            .create()
        retrofit = Retrofit.Builder()
            .baseUrl(BASEURL)
            .addConverterFactory(GsonConverterFactory.create(gson))
            .client(apiClient)
            .build()
        return retrofit
    }
}

• create interface

@GET("posts")
fun getresponse(): Call<ArrayList<ModelResponse?>?>?

• create model adapter

package com.example.using_kotlin_api_integretion

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView

class ModelAdapter(private val mList: List<ModelResponse>) : RecyclerView.Adapter<ModelAdapter.ViewHolder>() {

    // create new views
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        // inflates the card_view_design view
        // that is used to hold list item
        val view = LayoutInflater.from(parent.context)
            .inflate(R.layout.layout_row, parent, false)

        return ViewHolder(view)
    }

    // binds the list items to a view
    override fun onBindViewHolder(holder: ViewHolder, position: Int) {

//        val ItemsViewModel = mList[position]

        holder.textView1.setText(mList.get(position).getTitle())
        holder.textView2.setText(mList.get(position).getBody())
        holder.textView3.setText(mList.get(position).getUserId().toString())



    }

    // return the number of the items in the list
    override fun getItemCount(): Int {
        return mList.size
    }

    // Holds the views for adding it to image and text
    class ViewHolder(ItemView: View) : RecyclerView.ViewHolder(ItemView) {

        val textView1: TextView = itemView.findViewById(R.id.txtid)
        val textView2: TextView = itemView.findViewById(R.id.txtbody)
        val textView3: TextView = itemView.findViewById(R.id.txttitle)
    }
}

• in activity

package com.example.using_kotlin_api_integretion

import android.os.Bundle
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import com.example.using_kotlin_api_integretion.databinding.ActivityMainBinding
import retrofit2.Call
import retrofit2.Callback
import retrofit2.Response

class MainActivity : AppCompatActivity() {
    private lateinit var binding: ActivityMainBinding
    var apiInterface: ApiInterface?=null
    var apiModelResponse: ArrayList<ModelResponse>? = null
    var retrofit:RetrofitClass?=null


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding= ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        apiModelResponse = java.util.ArrayList()


       apiInterface= retrofit?.getRetrofit()?.create(ApiInterface::class.java)
        val call= apiInterface?.getresponse();
        call?.enqueue(object : Callback <ArrayList<ModelResponse>>{
            override fun onResponse(
                call: Call<ArrayList<ModelResponse>>,
                response: Response<ArrayList<ModelResponse>>
            ) {
               if(response.isSuccessful){
                   Toast.makeText(this@MainActivity,"done",Toast.LENGTH_SHORT)
               }
            }

            override fun onFailure(call: Call<ArrayList<ModelResponse>>, t: Throwable) {
                TODO("Not yet implemented")
                Toast.makeText(this@MainActivity,"not done",Toast.LENGTH_SHORT)
            }
        })

    }
}

private fun <T> Call<T>.enqueue(callback: Callback<ArrayList<ModelResponse>>) {

}