RecyclerView doesn't appear on screen - kotlin

Question

The list doesn't display on screen and it doesn't throw any error.
Am I doing something wrong connecting the adapter and layoutmanager?
Whenever I open the fragment it writes the following line: "W/RecyclerView: No adapter attached; skipping layout" and it doesn't change anything to the fragment.
This is the MainActivity.kt:
import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.EditText
import android.widget.ListView
import androidx.fragment.app.Fragment
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.google.android.material.bottomnavigation.BottomNavigationView
class MainActivity : AppCompatActivity() {
val addnewmoviefragment = AddNewMovieFragment()
val movielistfragment = MovieListFragment()
val moviedetailsfragment = MovieDetailsFragment()
private var layoutManager: RecyclerView.LayoutManager? = null
private var adapter: RecyclerView.Adapter<MovieListViewAdapter.ViewHolder>? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
replaceFragment(movielistfragment)
val movies: MutableList<Movies> = initList()
layoutManager = LinearLayoutManager(this)
adapter = MovieListViewAdapter(this, movies)
val button = findViewById<BottomNavigationView>(R.id.bottom_navigation)
button.setOnNavigationItemSelectedListener {
when(it.itemId){
R.id.ic_movieadd -> replaceFragment(addnewmoviefragment)
R.id.ic_moviedetails -> replaceFragment(movielistfragment)
}
true
}
//val submitButton = findViewById<Button>(R.id.submitButton)
//val cancelButton = findViewById<Button>(R.id.cancelButton)
}
private fun replaceFragment(fragment: Fragment){
if(fragment!=null){
val transaction = supportFragmentManager.beginTransaction()
transaction.replace(R.id.fragment_container, fragment)
transaction.commit()
}
}
private fun initList(): MutableList<Movies>{
return mutableListOf(
Movies(1, "Inception", "Very good movie!", "James Gun", Actors("Simeon")),
Movies(2, "Extracton", "Extracting!", "Christopher Nolan", Actors("Ivan"))
)
}
MovieListViewAdapter.kt
import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.BaseAdapter
import android.widget.EditText
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
class MovieListViewAdapter(val context: Context, val allMovies: MutableList<Movies>):
RecyclerView.Adapter<MovieListViewAdapter.ViewHolder>(){
class ViewHolder(view: View): RecyclerView.ViewHolder(view){
val id: TextView
val name: TextView
val description: TextView
val producer: TextView
val actors: TextView
init{
id = view.findViewById(R.id.movieId)
name = view.findViewById(R.id.movieNameId)
description = view.findViewById(R.id.movieDescriptionId)
producer = view.findViewById(R.id.movieProducerId)
actors = view.findViewById(R.id.movieActorsId)
}
}
override fun onCreateViewHolder(
parent: ViewGroup,
viewType: Int
): ViewHolder {
val view = LayoutInflater.from(parent.context).inflate(R.layout.recycler_view_row, parent, false)
return ViewHolder(view)
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val currentMovie: Movies = allMovies[position]
holder.id.text = currentMovie.id.toString()
holder.name.text = currentMovie.name
holder.description.text = currentMovie.description
holder.producer.text = currentMovie.producer
holder.actors.text = currentMovie.actors.toString()
}
override fun getItemCount(): Int {
return allMovies.size
}
}
MovieListFragment.kt
import android.content.Context
import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Toast
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
class MovieListFragment : Fragment() {
private var layoutManager: RecyclerView.LayoutManager? = null
private var adapter: RecyclerView.Adapter<MovieListViewAdapter.ViewHolder>? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
// Inflate the layout for this fragment
val view: View = inflater.inflate(R.layout.fragment_movie_list, container, false)
return view
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
Toast.makeText(context, "You are viewing the movie list!", Toast.LENGTH_SHORT).show()
}
}
Movies.kt
data class Movies(
val id: Int,
val name: String,
val description: String,
val producer: String,
val actors: Actors
) {
}
Actors.kt
data class Actors(
val name: String
){}
fragment_movie_list.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MovieListFragment">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/movieListId"
android:layout_width="389dp"
android:layout_height="589dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.246" />
</androidx.constraintlayout.widget.ConstraintLayout>
recycler_view_row.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/indexId"
android:layout_width="68dp"
android:layout_height="23dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.045"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.079" />
<TextView
android:id="#+id/nameId"
android:layout_width="68dp"
android:layout_height="21dp"
android:layout_marginBottom="620dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.046"
app:layout_constraintStart_toStartOf="parent" />
<TextView
android:id="#+id/descriptionId"
android:layout_width="68dp"
android:layout_height="19dp"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/nameId" />
<TextView
android:id="#+id/producerId"
android:layout_width="68dp"
android:layout_height="23dp"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/descriptionId" />
<TextView
android:id="#+id/actorsId"
android:layout_width="65dp"
android:layout_height="21dp"
android:layout_marginStart="16dp"
android:layout_marginTop="12dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/producerId" />
</androidx.constraintlayout.widget.ConstraintLayout>

Answer 1

From the code, I see that the adapter gets instantiated, but never attached to the recyclerView.
You are just missing the following line in the onViewCreated override in the fragment.
findViewById<RecyclerView>(R.id.movieListId).adapter = adapter
https://developer.android.com/guide/topics/ui/layout/recyclerview