How to use RecyclerView Adapter notifyDatasetChanged in Kotlin

In this android kotlin source code example, we are going to use notifyDatasetChanged() RecyclerView Adapter in Kotlin.

You can copy and adopt this source code example to your Kotlin android project without reinventing the wheel.

Below is a step by step source code to use notifyDatasetChanged() RecyclerView Adapter in Kotlin.

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=".recyclerView.RecyclerViewActivity10">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Update Data"
        android:textStyle="bold"
        android:background="@color/colorAccent"
        android:textColor="@color/white"
        android:onClick="update"
        app:layout_constraintBottom_toBottomOf="parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.kt

import android.content.Context
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.recyclerview.widget.RecyclerView
import com.bluapp.kotlinview.R
import androidx.recyclerview.widget.DividerItemDecoration
import androidx.recyclerview.widget.LinearLayoutManager
import android.widget.TextView
import android.view.LayoutInflater
import android.view.ViewGroup
import android.view.View


class RecyclerViewActivity10 : AppCompatActivity() {
    private var list: RecyclerView? = null
    private var recyclerAdapter: adapter? = null
    private var country: ArrayList<String>? = null


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_recycler_view10)
        list = findViewById(R.id.list) as RecyclerView
        country = arrayListOf<String>()
        country!!.add("Nigeria")
        country!!.add("China")
        country!!.add("USA")
        country!!.add("Ghana")
        country!!.add("Canada")
        country!!.add("Finland")

        val layoutManager = LinearLayoutManager(this)
        list!!.setLayoutManager(layoutManager)
        recyclerAdapter = adapter(this@RecyclerViewActivity10, country!!)
        list!!.addItemDecoration(DividerItemDecoration(list!!.getContext(), layoutManager.orientation))
        list!!.setAdapter(recyclerAdapter)

    }

    private inner class adapter(internal var context: Context, internal var mData: List<String>) :
        RecyclerView.Adapter<adapter.myViewHolder>() {
        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): adapter.myViewHolder {
            val view = LayoutInflater.from(context).inflate(R.layout.recyclerview_adapter1, parent, false)
            return myViewHolder(view)
        }
        override fun onBindViewHolder(holder: adapter.myViewHolder, position: Int) {
            holder.country.text = mData[position]
        }
        override fun getItemCount(): Int {
            return mData.size
        }
        inner class myViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
            internal var country: TextView
            init {
                country = itemView.findViewById(R.id.country)
            }
        }
    }

    fun update(view: View) {
        country!!.add("Denmark")
        country!!.add("Argentina")
        country!!.add("Andorra")
        country!!.add("Togo")
        recyclerAdapter!!.notifyDataSetChanged()
    }

}

recyclerview_adapter1.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="10dp">

    <TextView
        android:id="@+id/country"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:text="Country"
        android:textColor="#000000"
        android:textSize="18sp"
        android:textStyle="bold" />

</RelativeLayout>

If you have any question or suggestions kindly use the comment box or you can contact us directly through our contact page below.

Add a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.