How to add endless/infinite scroll to ViewPager2 in Kotlin

In this android kotlin source code example, we are going to add endless/infinite scroll to ViewPager2 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 add endless/infinite scroll to ViewPager2 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=".ViewPager.ViewPagerActivity18">

    <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.kt

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.fragment.app.Fragment
import androidx.fragment.app.FragmentManager
import androidx.lifecycle.Lifecycle
import androidx.viewpager2.adapter.FragmentStateAdapter
import androidx.viewpager2.widget.ViewPager2
import com.bluapp.kotlinview.R

class ViewPagerActivity18 : AppCompatActivity() {
    private var viewPager: ViewPager2? = null
    private val int_items = 5

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_view_pager18)
        viewPager = findViewById(R.id.viewpager) as ViewPager2
        viewPager!!.orientation = ViewPager2.ORIENTATION_HORIZONTAL
        viewPager!!.adapter = MyAdapter(supportFragmentManager, lifecycle)
        viewPager!!.registerOnPageChangeCallback(object :  ViewPager2.OnPageChangeCallback(){
            override fun onPageScrollStateChanged(state: Int) {
            }
            override fun onPageSelected(position: Int) {
                if((viewPager!!.currentItem+1)==int_items){
                    viewPager!!.setCurrentItem(0)
                }
            }
            override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {

            }
        })
    }

    private inner class MyAdapter(fm: FragmentManager?, lifecycle: Lifecycle) : FragmentStateAdapter(fm!!, lifecycle) {

        override fun createFragment(position: Int): Fragment {
            var fragment: Fragment? = null
            when (position) {
                0 -> fragment = ViewPagerFragment()
                1 -> fragment = ViewPagerFragment()
                2 -> fragment = ViewPagerFragment()
                3 -> fragment = ViewPagerFragment()
                4 -> fragment = ViewPagerFragment()
            }
            return fragment!!
        }


        override fun getItemCount(): Int {
            return int_items
        }

    }
}

fragment_view_pager.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#000000"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    tools:context=".ViewPager.ViewPagerFragment">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="ViewPagerFragment"
        android:textSize="20sp"
        android:textColor="@color/white"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>

ViewPagerFragment.kt

import android.os.Bundle
import androidx.fragment.app.Fragment
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import com.bluapp.kotlinview.R

class ViewPagerFragment : Fragment() {
    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_view_pager, container, false)
    }
}

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