Trying to fetch data from a JSON file and pass the data into fragment, but get an error - json

Question

I am new to Kotlin and Android Studio and I am tasked with creating a tab layout with 3 tabs and with view pager and fragments. Each fragment will have a list of songs from different genres: Rock, Pop, and Classic. I am given APIs and I created json files from these APIs. I created the Xmls and setup the layouts, adapters, data classes, and everything. Now I'm trying to get the data from the json file into the fragment using recycler view and card view. Here is the error I am getting:
Type mismatch: inferred type is MainActivity but List was expected and Classifier 'MyAdapter' does not have a companion object, and thus must be initialized here. Here is my code:
//Main Activity
package com.example.itunes_mysia
import android.os.Bundle
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import androidx.viewpager.widget.ViewPager
import com.google.android.material.tabs.TabLayout
import com.google.android.material.tabs.TabLayout.OnTabSelectedListener
import org.json.JSONException
import org.json.JSONObject
import java.io.IOException
import java.nio.charset.Charset
var artist_name: ArrayList<String> = ArrayList()
var track_name: ArrayList<String> = ArrayList()
var track_price: ArrayList<String> = ArrayList()
class MainActivity : AppCompatActivity() {
private lateinit var itunesToolbar: androidx.appcompat.widget.Toolbar
private lateinit var itunesTabs: TabLayout
private lateinit var itunesTitleText: TextView
private lateinit var itunesViewPager: ViewPager
private lateinit var itunesPagerAdapters: PagerAdapters
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
title = "KotlinApp"
val recyclerView = findViewById<RecyclerView>(R.id.recycler_view)
val linearLayoutManager = LinearLayoutManager(applicationContext)
recyclerView.layoutManager = linearLayoutManager
try {
val obj = JSONObject(loadJSONFromAsset())
val rockArray = obj.getJSONArray("Rock")
for (i in 0 until rockArray.length()) {
val userDetail = rockArray.getJSONObject(i)
artist_name.add(userDetail.getString("Artist"))
track_name.add(userDetail.getString("Track Name"))
track_price.add(userDetail.getString("Track Price"))
}
}
catch (e: JSONException) {
e.printStackTrace()
}
val myAdapter = MyAdapter(this#MainActivity)
recyclerView.adapter = MyAdapter
// Set find ID
itunesToolbar = findViewById(R.id.itunesToolbar)
itunesTitleText = findViewById(R.id.itunesTitleText)
itunesTabs = findViewById(R.id.itunesTabs)
itunesViewPager = findViewById(R.id.itunesViewPager)
itunesPagerAdapters = PagerAdapters(supportFragmentManager)
// Set Toolbar
itunesToolbar.setTitle("")
itunesTitleText.setText(getString(R.string.itunes))
setSupportActionBar(findViewById(R.id.itunesToolbar))
// Set Fragment List
itunesPagerAdapters.addfragment(RockFragment(), "Rock")
itunesPagerAdapters.addfragment(ClassicFFragment(), "Classic")
itunesPagerAdapters.addfragment(PopFragment(), "Pop")
// Set View Pager Adapter
itunesViewPager.adapter = itunesPagerAdapters
// Set Tab Layout with View Pager Adapter
itunesTabs.setupWithViewPager(itunesViewPager)
// Set Icons
itunesTabs.getTabAt(0)!!.setIcon(R.mipmap.music1)
itunesTabs.getTabAt(1)!!.setIcon(R.mipmap.music2)
itunesTabs.getTabAt(2)!!.setIcon(R.mipmap.music3)
}
class ViewPagerOnTabSelectedListener(private val viewPager: ViewPager) :
OnTabSelectedListener {
override fun onTabSelected(tab: TabLayout.Tab) {
viewPager.currentItem = tab.position
}
override fun onTabUnselected(tab: TabLayout.Tab?) {
// No-op
}
override fun onTabReselected(tab: TabLayout.Tab?) {
// No-op
}
}
private fun loadJSONFromAsset(): String {
val json: String?
try {
val inputStream = assets.open("rock.json")
val size = inputStream.available()
val buffer = ByteArray(size)
val charset: Charset = Charsets.UTF_8
inputStream.read(buffer)
inputStream.close()
json = String(buffer, charset)
}
catch (ex: IOException) {
ex.printStackTrace()
return ""
}
return json
}
}
//MyAdapter.kt (for recycler view)
package com.example.itunes_mysia
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
class MyAdapter(private val Rock: List<Rock>) :
RecyclerView.Adapter<MyAdapter.MyViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int):
MyViewHolder {
val itemView= LayoutInflater.from(parent.context).inflate(R.layout.row, parent,
false)
return MyViewHolder(itemView)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val currentItem = Rock[position]
holder.artistName.text = currentItem.artistName
holder.trackName.text = currentItem.trackName
holder.trackPrice.text = currentItem.trackPrice
}
override fun getItemCount(): Int {
return Rock.size
}
class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val artistName: TextView = itemView.findViewById(R.id.art_name)
val trackName: TextView = itemView.findViewById(R.id.trackName)
val trackPrice: TextView = itemView.findViewById(R.id.trackPrice)
}
}