Using recycleview in android - kotlin

Question

I read some document about using recyclingview for activity. Now i try to use recycleview to my fragment. the problem is my fragment look empty when i execute.
fragment:
class KategoriFragment : Fragment() {
var araclarKategori = ArrayList<AracMarka>()
private lateinit var galleryViewModel: GalleryViewModel
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
veriKaynaginiDoldur()
galleryViewModel =
ViewModelProviders.of(this).get(GalleryViewModel::class.java)
var root = inflater.inflate(R.layout.fragment_category, container, false)
veriKaynaginiDoldur()
var rvarackategori = root.findViewById(R.id.rvarackategori) as RecyclerView
var MyAdapter = AracMarkaAdapter(araclarKategori)
rvarackategori.adapter = MyAdapter
/
return root
}
fun veriKaynaginiDoldur(): ArrayList<AracMarka> {
var aracLogo = arrayOf(R.drawable.opellogo, R.drawable.chevroletlogo)
var aracismi = resources.getStringArray(R.array.arabaisim)
for (i in 0 until min(aracismi.size, aracLogo.size)) {
var eklenecekaracKategori = AracMarka(aracismi[i], aracLogo[i])
araclarKategori.add(eklenecekaracKategori)
}
return araclarKategori
}
}
I create an adapter. I think there is no problem on it.
adapter:
class AracMarkaAdapter(tumKategori: ArrayList<AracMarka>) :
RecyclerView.Adapter<AracMarkaAdapter.AracMarkaViewHolder>() {
var araclar = tumKategori
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): AracMarkaViewHolder {
var inflater = LayoutInflater.from(parent.context)
var arackategori = inflater.inflate(R.layout.arac_kategori, parent, false)
return AracMarkaViewHolder(arackategori)
}
override fun getItemCount(): Int {
return araclar.size
}
override fun onBindViewHolder(holder: AracMarkaViewHolder, position: Int) {
holder.aracismi.text=araclar.get(position).aracAdi
holder.aracLogo.setImageResource(araclar.get(position).aracLogo)
}
class AracMarkaViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
var teksatirKategori= itemView
var aracismi= teksatirKategori.tvaracAdi
var aracLogo=teksatirKategori.img_arac_sembol
}
}
fragment 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">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rvarackategori"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
So, when i click button, fragment opens but it is empty. Do you have any idea about it?

Answer 1

After modifying the data in your list in veriKaynaginiDoldur(), you need to call myAdapter.notifyDataSetChanged() so it knows to rebind the data. Or you could call veriKaynaginiDoldur() before you instantiate your adapter.
Edit: Your other error is in your for loop within veriKaynaginiDoldur(). You are making a range using the size of the araclarKategori list when it is still zero.
Instead of
for (i in 0..araclarKategori.size - 1)
use
for (i in 0 until min(aracLogo.size, aracismi.size))

Answer 2

you have to call this veriKaynaginiDoldur() function after the below
lines of code below I have mentioned please check
var rvarackategori = root.findViewById(R.id.rvarackategori) as RecyclerView
var MyAdapter = AracMarkaAdapter(araclarKategori)
rvarackategori.adapter = MyAdapter
veriKaynaginiDoldur()