Kotlin class cannot findViweById-CodePudding

maybe there is a simple reason. I cannot find it... My findViewById does not find any IDs of my project. So, R.id.name cannot be found, same for R.layout.item.

This is my code:


class RVAdapter(persons: List<Person>?): RecyclerView.Adapter<RVAdapter.PersonViewHolder>() {
    inner class PersonViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var cv: CardView
        var personName: TextView
        var personAge: TextView

        init {
            cv = this.itemView.findViewById(R.id.cv)
            personName = this.itemView.findViewById(R.id.person_name)
            personAge = this.itemView.findViewById(R.id.person_honor)
        }
    }

    var persons: List<Person>? = null

    init {
        this.persons = persons
    }

    override fun getItemCount(): Int {
        return persons!!.size
    }

    override fun onCreateViewHolder(viewGroup: ViewGroup, i: Int): PersonViewHolder {
        val v: View =
            LayoutInflater.from(viewGroup.context).inflate(R.layout.item, viewGroup, false)
        return PersonViewHolder(v)
    }

    override fun onBindViewHolder(personViewHolder: PersonViewHolder, i: Int) {
        personViewHolder.personName.text = persons!![i].name
        personViewHolder.personAge.setText(persons!![i].honor)
    }

}

The IDs are in a XML file definitly excactly like in the code. I put

 buildFeatures{
        viewBinding=true
    }

to my gradle file but it doesn´t work.

Any ideas?

CodePudding user response：

Remove R package and re-import it. May be there is the problem while we copy paste the codes.

Or you can use binding in your adapter -> https://www.geeksforgeeks.org/how-to-use-view-binding-in-recyclerview-adapter-class-in-android/

CodePudding user response：

Holder Class

 inner class PersonViewHolder(val binding: LayoutItemBinding) :
            RecyclerView.ViewHolder(binding.root)

onCreateviewHolder override method

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): PersonViewHolder{
   return PersonViewHolder(
            LayoutItemBinding.inflate(
                LayoutInflater.from(parent.context),
                parent,
                false
            )
        )}

onBindViewHolder override method

override fun onBindViewHolder(holder: PersonViewHolder, position: Int) {
  
       holder.binding.name.text="what you need"      
 }