Kotlin Recyclerview row item selection background color change

Question

I am able to change the color of the text and background of row clicked of my recyclerview in my recyclerview.

But my probl

Answer 1

After a thorough search on the Internet, I was finally able to solve this problem.
I put the code step by step and give explanations if needed.

1 - create new android studio project
2 - cods for activity_main.xml as below:
activity_main.xml

3 - create a layout for recycler view row(item) with name item_list.xml as bellow
item_list.xml

4 - create data class(Based on the data you want to bind in RecyclerView) as bellow

My Model(UserModel.kt)

    public data class UserModel(var title:String,var name:String,var isSelected:Boolean=false) 

5 - create Adapter for your RecyclerView as bellow

CustomAdapter.kt

class CustomAdapter(private val context: Context, private val list: ArrayList,
private val listener: OnItemClickListener
                    ) : RecyclerView.Adapter() {

    private inner class ViewHolder internal constructor(itemView: View) : RecyclerView.ViewHolder(itemView),View.OnClickListener {

        internal var tvLabel: TextView
        internal var tvName: TextView

        init {
            tvLabel = itemView.findViewById(R.id.tv_label) // Initialize your All views prensent in list items
            tvName = itemView.findViewById(R.id.tv_name) // Initialize your All views prensent in list items
            itemView.setOnClickListener(this)
        }

        internal fun bind(position: Int) {
            // This method will be called anytime a list item is created or update its data
            //Do your stuff here
            tvLabel.text = list[position].title
            tvName.text = list[position].name
        }

        override fun onClick(v: View?) {
            val position:Int = adapterPosition
            if(position != RecyclerView.NO_POSITION) {
                listener.onItemClick(position,this@CustomAdapter,itemView)
            }
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        return ViewHolder(LayoutInflater.from(context).inflate(R.layout.item_list, parent, false))
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        if(list[position].isSelected){
            holder.itemView.setBackgroundColor(Color.YELLOW)
            holder.itemView.findViewById(R.id.linear_content).setBackgroundColor(Color.YELLOW)
        } else{
            holder.itemView.setBackgroundColor(Color.WHITE)
            holder.itemView.findViewById(R.id.linear_content).setBackgroundColor(Color.WHITE)
        }
        (holder as ViewHolder).bind(position)
    }

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

    interface OnItemClickListener{
        fun onItemClick(position: Int,adapter:CustomAdapter,v:View)
    }
}  

6 - codes for MainActivity.kt as bellow:
MainActivity.kt

class MainActivity : AppCompatActivity(),CustomAdapter.OnItemClickListener {
    private val data = arrayListOf()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main_page)

        val recyclerview = findViewById(R.id.recycler_view)

        data.add(UserModel(title = "item 1",name = "name 1"))
        data.add(UserModel(title = "item 2",name = "name 2"))
        data.add(UserModel(title = "item 3",name = "name 3"))
        data.add(UserModel(title = "item 4",name = "name 4"))
        data.add(UserModel(title = "item 5",name = "name 5"))
        data.add(UserModel(title = "item 6",name = "name 6"))
        data.add(UserModel(title = "item 1",name = "name 1"))
        data.add(UserModel(title = "item 2",name = "name 2"))
        data.add(UserModel(title = "item 3",name = "name 3"))
        data.add(UserModel(title = "item 4",name = "name 4"))
        data.add(UserModel(title = "item 5",name = "name 5"))
        data.add(UserModel(title = "item 6",name = "name 6"))
 

        val adapter = CustomAdapter(this,data,this)
        recyclerview.layoutManager = LinearLayoutManager(this)
        recyclerview.adapter = adapter
        recyclerview.setHasFixedSize(true)

    }


    override fun onItemClick(position: Int,adapter: CustomAdapter,v:View) {
        val clicked_item:UserModel = data[position]
        clicked_item.title = "clicked"
        clicked_item.isSelected = !clicked_item.isSelected
        if(clicked_item.isSelected){
            recycler_view.getChildAt(recycler_view.indexOfChild(v)).setBackgroundColor(Color.YELLOW)
            recycler_view.getChildAt(recycler_view.indexOfChild(v)).findViewById(R.id.linear_content).setBackgroundColor(Color.YELLOW)
        }else{
            recycler_view.getChildAt(recycler_view.indexOfChild(v)).setBackgroundColor(Color.WHITE)
            recycler_view.getChildAt(recycler_view.indexOfChild(v)).findViewById(R.id.linear_content).setBackgroundColor(Color.WHITE)
        }

    }

}  

I hope you find it useful