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

You have to set color for other items when you cal

Answer 2

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

<?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=".MainPageActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:drawable/screen_background_light_transparent"
        tools:listitem="@layout/item_list" />
</androidx.constraintlayout.widget.ConstraintLayout>  

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

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <LinearLayout
        android:id="@+id/linear_content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="3"
        android:background="#FFFFFF"
        android:orientation="vertical"
        android:padding="5dp">

        <TextView
            android:id="@+id/tv_label"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="right"
            android:text="TextView"
            android:textColor="#000000" />

        <TextView
            android:id="@+id/tv_name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center|right"
            android:text="TextView"
            android:textColor="#000000" />

    </LinearLayout>

    <ImageView
        android:id="@+id/img_chanel"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:layout_weight="1"
        app:srcCompat="@mipmap/ic_launcher" />

</LinearLayout>  

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<UserModel>,
private val listener: OnItemClickListener
                    ) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    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<LinearLayout>(R.id.linear_content).setBackgroundColor(Color.YELLOW)
        } else{
            holder.itemView.setBackgroundColor(Color.WHITE)
            holder.itemView.findViewById<LinearLayout>(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<UserModel>()

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

        val recyclerview = findViewById<RecyclerView>(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<LinearLayout>(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<LinearLayout>(R.id.linear_content).setBackgroundColor(Color.WHITE)
        }

    }

}  

I hope you find it useful