Scroll RecyclerView to show the selected item on top

Priyanka Kumari

28 November 2023

In this blog, we are going to learn about how to scroll RecyclerView to show the selected item on top. We will cover the Android scrolling flow part in this blog. So let’s get started.

An OnScrollListener can be added to a RecyclerView to receive messages when a scrolling event has occurred on that RecyclerView.

When the recycler views vertically scrolls, then the selected item is centered or on the Top First item, and then the item is automatically centered or to be the first when the item to be selected is set.

Let’s understand this with an example.

1.) At the very first, we have to create the one activity class in which the recycler is a vertical orientation.

An OnScrollListener can be added to a RecyclerView to receive messages when a scrolling event has occurred on that RecyclerView.

We have a RecyclerView list, in which I want the currently selected item to be shown at the top of the RecyclerView. I still, however, want the entire list to be scrollable, therefore, removing views from above the selected item is not a possible solution.

We create the XML part of the MainActivity UI part named activity_main

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

<androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

<androidx.constraintlayout.widget.ConstraintLayout
                android:id="@+id/constraint_multiple_options"
                android:layout_width="match_parent"
                android:layout_height="0dp"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintEnd_toEndOf="parent"
                app:layout_constraintStart_toStartOf="parent"
                app:layout_constraintTop_toTopOf="parent">

<com.google.android.material.tabs.TabLayout
                    android:id="@+id/tabs"
                    style="@style/MyCustomTabLayout"
                    android:layout_width="0dp"
                    android:layout_height="60.4dp"
                    android:layout_marginTop="10dp"
                    android:elevation="5dp"
                    android:gravity="start"
                    android:tabStripEnabled="false"
                    android:textAlignment="viewStart"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toTopOf="parent"
                    app:tabGravity="fill"
                    app:tabIndicatorColor="@android:color/transparent"
                    app:tabIndicatorHeight="0dp"
                    app:tabMode="scrollable"
                    app:tabTextAppearance="@style/MyCustomTextAppearance" />

<androidx.recyclerview.widget.RecyclerView
                    android:id="@+id/linear_recycler_menuItem"
                    android:layout_width="match_parent"
                    android:layout_height="0dp"
                    android:layout_marginTop="12dp"
                    android:orientation="vertical"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toBottomOf="@id/tabs" />

</androidx.constraintlayout.widget.ConstraintLayout>

<androidx.cardview.widget.CardView
                android:id="@+id/card_menu_list"
                android:layout_width="252dp"
                android:layout_height="wrap_content"
                android:layout_above="@id/linear_menubtn"
                android:layout_alignParentEnd="true"
                android:layout_alignParentRight="true"
                android:layout_marginEnd="19dp"
                android:layout_marginRight="19dp"
                android:layout_marginBottom="@dimen/margin_20"
                android:elevation="10dp"
                android:visibility="gone"
                app:cardBackgroundColor="@color/white"
                app:cardCornerRadius="10dp">

<androidx.recyclerview.widget.RecyclerView
                    android:id="@+id/menuListing"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:layout_marginHorizontal="20dp"
                    android:layout_marginTop="15dp"
                    android:layout_marginBottom="15dp"
                    android:gravity="start"
                    android:textAlignment="viewStart"
                    app:layout_constraintBottom_toBottomOf="parent"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toTopOf="parent" />

</androidx.cardview.widget.CardView>

</LinearLayout>
        </RelativeLayout>
    </RelativeLayout>

</RelativeLayout>

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

<RelativeLayout 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="match_parent">

<RelativeLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:visibility="visible">

<androidx.constraintlayout.widget.ConstraintLayout

android:layout_width="match_parent"

android:layout_height="match_parent">

<androidx.constraintlayout.widget.ConstraintLayout

android:id="@+id/constraint_multiple_options"

android:layout_width="match_parent"

android:layout_height="0dp"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toTopOf="parent">

<com.google.android.material.tabs.TabLayout

android:id="@+id/tabs"

style="@style/MyCustomTabLayout"

android:layout_width="0dp"

android:layout_height="60.4dp"

android:layout_marginTop="10dp"

android:elevation="5dp"

android:gravity="start"

android:tabStripEnabled="false"

android:textAlignment="viewStart"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toTopOf="parent"

app:tabGravity="fill"

app:tabIndicatorColor="@android:color/transparent"

app:tabIndicatorHeight="0dp"

app:tabMode="scrollable"

app:tabTextAppearance="@style/MyCustomTextAppearance" />

<androidx.recyclerview.widget.RecyclerView

android:id="@+id/linear_recycler_menuItem"

android:layout_width="match_parent"

android:layout_height="0dp"

android:layout_marginTop="12dp"

android:orientation="vertical"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toBottomOf="@id/tabs" />

</androidx.constraintlayout.widget.ConstraintLayout>

<LinearLayout

android:id="@+id/mTransparent"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:background="@color/transparent_color"

android:orientation="vertical"

android:visibility="gone" />

<RelativeLayout

android:layout_width="match_parent"

android:layout_height="match_parent"

android:layout_alignParentBottom="true"

android:layout_marginTop="50dp"

android:background="@android:color/transparent"

android:orientation="vertical"

android:paddingTop="50dp">

<androidx.cardview.widget.CardView

android:id="@+id/card_menu_list"

android:layout_width="252dp"

android:layout_height="wrap_content"

android:layout_above="@id/linear_menubtn"

android:layout_alignParentEnd="true"

android:layout_alignParentRight="true"

android:layout_marginEnd="19dp"

android:layout_marginRight="19dp"

android:layout_marginBottom="@dimen/margin_20"

android:elevation="10dp"

android:visibility="gone"

app:cardBackgroundColor="@color/white"

app:cardCornerRadius="10dp">

<androidx.recyclerview.widget.RecyclerView

android:id="@+id/menuListing"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:layout_marginHorizontal="20dp"

android:layout_marginTop="15dp"

android:layout_marginBottom="15dp"

android:gravity="start"

android:textAlignment="viewStart"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toTopOf="parent" />

</androidx.cardview.widget.CardView>

<LinearLayout

android:id="@+id/linear_menubtn"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_alignParentBottom="true"

android:orientation="vertical">

<Button

android:id="@+id/menu_btn"

android:layout_width="105.6dp"

android:layout_height="45.9dp"

android:layout_alignParentEnd="true"

android:layout_alignParentRight="true"

android:layout_gravity="end"

android:layout_marginEnd="18dp"

android:layout_marginRight="18dp"

android:layout_marginBottom="18dp"

android:background="@drawable/rounded_all_side_pink"

android:padding="10dp"

android:text="Menu"

android:textColor="@color/white" />

</LinearLayout>

</RelativeLayout>

In the styles, “MyCustomTabLayout” you can add it.

<item name="tabTextAppearance">@style/MyCustomTextAppearance</item>

<item name="tabSelectedTextColor">@color/white</item>

</style>

<item name="textAllCaps">false</item>

<item name="android:color">@color/black</item>

<item name="android:textColor">@color/black</item>

</style>

In the Colors, you can add them below.

<color name="white">#FFFFFF</color>

You can create in Drawable, an XML file named “rounded_all_side_pink”

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

<stroke

android:width="2dp"

android:color="@color/colorPrimary" />

</shape>

2.) The Scrolling view can be performed by using the onScrollListener()

We take only dummy data for showing the items as in 20 dummy data in the ArrayList.

The callback method is to be invoked when the RecyclerView has been scrolled. This will be called after the scroll has been completed.

This callback will also be called if the visible item range changes after a layout calculation. In that case, dx and dy will be 0.

class RecyclerListingActivity : AppCompatActivity() {
    private var responseItemList: MutableList<String>? = ArrayList()
    private var linearLayoutManager: LinearLayoutManager? = null
    private var menuListAdapter: MenuListAdapter? = null
    private var dailyCakeListScrollAdapter: DailyCakeListScrollAdapter? = null
    private var flagCheck = false
    private var checkCallBack = false
    private var checkScroll = true
    private var posSelected = 0
    private var totalCount = 0

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_recycler_listing)
        setData()
    }

private fun setData() {
        responseItemList?.add("test1")
        responseItemList?.add("test2")
        responseItemList?.add("test3")
        responseItemList?.add("test4")
        responseItemList?.add("test5")
        responseItemList?.add("test6")
        responseItemList?.add("test7")
        responseItemList?.add("test8")
        responseItemList?.add("test9")
        responseItemList?.add("test10")
        responseItemList?.add("test11")
        responseItemList?.add("test12")
        responseItemList?.add("test13")
        responseItemList?.add("test14")
        responseItemList?.add("test15")
        responseItemList?.add("test16")
        responseItemList?.add("test17")
        responseItemList?.add("test18")
        responseItemList?.add("test19")
        responseItemList?.add("test20")
        linearLayoutManager = LinearLayoutManager(this@RecyclerListingActivity, LinearLayoutManager.VERTICAL, false)
        linear_recycler_menuItem.layoutManager = linearLayoutManager
        menuListing.layoutManager = LinearLayoutManager(
            this@RecyclerListingActivity,
            LinearLayoutManager.VERTICAL,
            false
        )
        setTabs()
    }

private fun setTabs() {
        for (aq in responseItemList!!.indices) {
            tabs!!.addTab(tabs!!.newTab().setText(responseItemList!![aq]))
            tabs!!.tabGravity = TabLayout.GRAVITY_FILL
        }
        setAdapter()
    }

private fun setAdapter() {
        setMenuAdapter()
        initCategoryMenu()
    }

fun bindWidgetsWithAnEvent() {
        tabs!!.addOnTabSelectedListener(object : OnTabSelectedListener {
            override fun onTabSelected(tab: TabLayout.Tab) {
                checkCallBack = true
                posSelected = tab.position
                linear_recycler_menuItem!!.smoothScrollToPosition(tab.position)
                tabs!!.setSelectedTabIndicatorHeight((2 * resources.displayMetrics.density).toInt())
                selectionBackground(posSelected)
                if (tab.position == totalCount - 1) {
                    checkCallBack = false
                }
            }

override fun onTabUnselected(tab: TabLayout.Tab) {
                checkCallBack = false
            }

override fun onTabReselected(tab: TabLayout.Tab) {
                checkCallBack = true
                posSelected = tab.position
                selectionBackground(posSelected)
                linear_recycler_menuItem!!.smoothScrollToPosition(tab.position)
                tabs!!.setSelectedTabIndicatorHeight((2 * resources.displayMetrics.density).toInt())
                selectionBackground(posSelected)
                if (tab.position == totalCount - 1) {
                    checkCallBack = false
                }
            }
        })
    }

private fun initCategoryMenu() {
        dailyCakeListScrollAdapter =
            DailyCakeListScrollAdapter(responseItemList!!)
        linear_recycler_menuItem!!.adapter = dailyCakeListScrollAdapter
        setScrollListener()
        bindWidgetsWithAnEvent()
    }

private fun setScrollListener() {
        checkScroll = true
        linear_recycler_menuItem!!.addOnScrollListener(object : RecyclerView.OnScrollListener() {
            override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
                super.onScrollStateChanged(recyclerView, newState)
                val visiblePosition = linearLayoutManager!!.findFirstVisibleItemPosition()
                val firstCompletelyVisiblePosition =
                    linearLayoutManager!!.findFirstCompletelyVisibleItemPosition()
                totalCount = linearLayoutManager!!.itemCount
                checkScroll = false
                if (visiblePosition > -1) {
                    if (!checkCallBack) {
                        if (firstCompletelyVisiblePosition == -1) {
                            selectionBackground(visiblePosition)
                            tabs!!.setScrollPosition(visiblePosition, 0f, true)
                        } else {
                            selectionBackground(firstCompletelyVisiblePosition)
                            tabs!!.setScrollPosition(firstCompletelyVisiblePosition, 0f, true)
                        }
                    } else {
                        selectionBackground(posSelected)
                        tabs!!.setScrollPosition(posSelected, 0f, true)
                        if (firstCompletelyVisiblePosition == posSelected) {
                            checkCallBack = false
                        }
                    }
                }
            }
        })
    }

private fun selectionBackground(position: Int) {
        for (i in responseItemList!!.indices) {
            if (i == position) {
                val tabLayout =
                    (tabs!!.getChildAt(0) as ViewGroup).getChildAt(position) as LinearLayout
                val tabTextView = tabLayout.getChildAt(1) as TextView
                if (tabTextView != null) {
                    tabTextView.setTextColor(Color.parseColor("#ffffff"))
                    tabTextView.setPadding(11, 7, 11, 7)
                    tabTextView.setBackgroundResource(R.drawable.rounded_all_side_pink)
                }
                val tab = (tabs!!.getChildAt(0) as ViewGroup).getChildAt(position)
                val p = tab.layoutParams as MarginLayoutParams
                p.setMargins(0, 0, 0, 0)
                tab.requestLayout()
                tabs!!.isSmoothScrollingEnabled = true
                tabs!!.setScrollPosition(position, 0f, true)
            } else {
                val tabLayout = (tabs!!.getChildAt(0) as ViewGroup).getChildAt(i) as LinearLayout
                val tabTextView = tabLayout.getChildAt(1) as TextView
                if (tabTextView != null) {
                    tabTextView.setPadding(11, 7, 11, 7)
                    tabTextView.setTextColor(Color.parseColor("#000000"))
                    tabTextView.setBackgroundResource(R.drawable.rounded_all_side_transparent)
                }
                val tab = (tabs!!.getChildAt(0) as ViewGroup).getChildAt(i)
                val p = tab.layoutParams as MarginLayoutParams
                p.setMargins(0, 0, 0, 0)
                tab.requestLayout()
            }
        }
    }

private fun setMenuAdapter() {
        menuListAdapter = MenuListAdapter(
            responseItemList!!,
            object : MenuListAdapter.OnItemClickListener {
                override fun onItemClick(position: Int, check: Boolean) {
                    checkCallBack = check
                    posSelected = position
                    mTransparent!!.visibility = View.GONE
                    card_menu_list!!.visibility = View.GONE
                    flagCheck = false
                    tabs!!.isSmoothScrollingEnabled = true
                    selectionBackground(position)
                    tabs!!.setScrollPosition(position, 0f, true)
                    linear_recycler_menuItem!!.smoothScrollToPosition(position)
                }
            })
        menuListing!!.adapter = menuListAdapter
        menu_btn!!.setOnClickListener {
            if (!flagCheck) {
                checkCallBack = false
                mTransparent!!.visibility = View.VISIBLE
                card_menu_list!!.visibility = View.VISIBLE
                flagCheck = true
            } else {
                checkCallBack = false
                mTransparent!!.visibility = View.GONE
                card_menu_list!!.visibility = View.GONE
                flagCheck = false
            }
        }
    }
}

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class RecyclerListingActivity : AppCompatActivity() {

private var responseItemList: MutableList<String>? = ArrayList()

private var linearLayoutManager: LinearLayoutManager? = null

private var menuListAdapter: MenuListAdapter? = null

private var dailyCakeListScrollAdapter: DailyCakeListScrollAdapter? = null

private var flagCheck = false

private var checkCallBack = false

private var checkScroll = true

private var posSelected = 0

private var totalCount = 0

override fun onCreate(savedInstanceState: Bundle?) {

super.onCreate(savedInstanceState)

setContentView(R.layout.activity_recycler_listing)

setData()

}

private fun setData() {

responseItemList?.add("test1")

responseItemList?.add("test2")

responseItemList?.add("test3")

responseItemList?.add("test4")

responseItemList?.add("test5")

responseItemList?.add("test6")

responseItemList?.add("test7")

responseItemList?.add("test8")

responseItemList?.add("test9")

responseItemList?.add("test10")

responseItemList?.add("test11")

responseItemList?.add("test12")

responseItemList?.add("test13")

responseItemList?.add("test14")

responseItemList?.add("test15")

responseItemList?.add("test16")

responseItemList?.add("test17")

responseItemList?.add("test18")

responseItemList?.add("test19")

responseItemList?.add("test20")

linearLayoutManager = LinearLayoutManager(this@RecyclerListingActivity, LinearLayoutManager.VERTICAL, false)

linear_recycler_menuItem.layoutManager = linearLayoutManager

menuListing.layoutManager = LinearLayoutManager(

this@RecyclerListingActivity,

LinearLayoutManager.VERTICAL,

false

)

setTabs()

}

private fun setTabs() {

for (aq in responseItemList!!.indices) {

tabs!!.addTab(tabs!!.newTab().setText(responseItemList!![aq]))

tabs!!.tabGravity = TabLayout.GRAVITY_FILL

}

setAdapter()

}

private fun setAdapter() {

setMenuAdapter()

initCategoryMenu()

}

fun bindWidgetsWithAnEvent() {

tabs!!.addOnTabSelectedListener(object : OnTabSelectedListener {

override fun onTabSelected(tab: TabLayout.Tab) {

checkCallBack = true

posSelected = tab.position

linear_recycler_menuItem!!.smoothScrollToPosition(tab.position)

tabs!!.setSelectedTabIndicatorHeight((2 * resources.displayMetrics.density).toInt())

selectionBackground(posSelected)

if (tab.position == totalCount - 1) {

checkCallBack = false

}

override fun onTabUnselected(tab: TabLayout.Tab) {

checkCallBack = false

}

override fun onTabReselected(tab: TabLayout.Tab) {

checkCallBack = true

posSelected = tab.position

selectionBackground(posSelected)

linear_recycler_menuItem!!.smoothScrollToPosition(tab.position)

tabs!!.setSelectedTabIndicatorHeight((2 * resources.displayMetrics.density).toInt())

selectionBackground(posSelected)

if (tab.position == totalCount - 1) {

checkCallBack = false

}

})

}

private fun initCategoryMenu() {

dailyCakeListScrollAdapter =

DailyCakeListScrollAdapter(responseItemList!!)

linear_recycler_menuItem!!.adapter = dailyCakeListScrollAdapter

setScrollListener()

bindWidgetsWithAnEvent()

}

private fun setScrollListener() {

checkScroll = true

linear_recycler_menuItem!!.addOnScrollListener(object : RecyclerView.OnScrollListener() {

override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {

super.onScrollStateChanged(recyclerView, newState)

val visiblePosition = linearLayoutManager!!.findFirstVisibleItemPosition()

val firstCompletelyVisiblePosition =

linearLayoutManager!!.findFirstCompletelyVisibleItemPosition()

totalCount = linearLayoutManager!!.itemCount

checkScroll = false

if (visiblePosition > -1) {

if (!checkCallBack) {

if (firstCompletelyVisiblePosition == -1) {

selectionBackground(visiblePosition)

tabs!!.setScrollPosition(visiblePosition, 0f, true)

} else {

selectionBackground(firstCompletelyVisiblePosition)

tabs!!.setScrollPosition(firstCompletelyVisiblePosition, 0f, true)

}

} else {

selectionBackground(posSelected)

tabs!!.setScrollPosition(posSelected, 0f, true)

if (firstCompletelyVisiblePosition == posSelected) {

checkCallBack = false

}

})

}

private fun selectionBackground(position: Int) {

for (i in responseItemList!!.indices) {

if (i == position) {

val tabLayout =

(tabs!!.getChildAt(0) as ViewGroup).getChildAt(position) as LinearLayout

val tabTextView = tabLayout.getChildAt(1) as TextView

if (tabTextView != null) {

tabTextView.setTextColor(Color.parseColor("#ffffff"))

tabTextView.setPadding(11, 7, 11, 7)

tabTextView.setBackgroundResource(R.drawable.rounded_all_side_pink)

}

val tab = (tabs!!.getChildAt(0) as ViewGroup).getChildAt(position)

val p = tab.layoutParams as MarginLayoutParams

p.setMargins(0, 0, 0, 0)

tab.requestLayout()

tabs!!.isSmoothScrollingEnabled = true

tabs!!.setScrollPosition(position, 0f, true)

} else {

val tabLayout = (tabs!!.getChildAt(0) as ViewGroup).getChildAt(i) as LinearLayout

val tabTextView = tabLayout.getChildAt(1) as TextView

if (tabTextView != null) {

tabTextView.setPadding(11, 7, 11, 7)

tabTextView.setTextColor(Color.parseColor("#000000"))

tabTextView.setBackgroundResource(R.drawable.rounded_all_side_transparent)

}

val tab = (tabs!!.getChildAt(0) as ViewGroup).getChildAt(i)

val p = tab.layoutParams as MarginLayoutParams

p.setMargins(0, 0, 0, 0)

tab.requestLayout()

}

private fun setMenuAdapter() {

menuListAdapter = MenuListAdapter(

responseItemList!!,

object : MenuListAdapter.OnItemClickListener {

override fun onItemClick(position: Int, check: Boolean) {

checkCallBack = check

posSelected = position

mTransparent!!.visibility = View.GONE

card_menu_list!!.visibility = View.GONE

flagCheck = false

tabs!!.isSmoothScrollingEnabled = true

selectionBackground(position)

tabs!!.setScrollPosition(position, 0f, true)

linear_recycler_menuItem!!.smoothScrollToPosition(position)

}

})

menuListing!!.adapter = menuListAdapter

menu_btn!!.setOnClickListener {

if (!flagCheck) {

checkCallBack = false

mTransparent!!.visibility = View.VISIBLE

card_menu_list!!.visibility = View.VISIBLE

flagCheck = true

} else {

checkCallBack = false

mTransparent!!.visibility = View.GONE

card_menu_list!!.visibility = View.GONE

flagCheck = false

}

Here, An OnScrollListener can be added to a RecyclerView to receive messages when a scrolling event has occurred on that RecyclerView.

We added one TabLayout under which the items get the scroll, and below the tab’s layout, there is Recyclerview in which all items get scrolled vertically.

3.) After that for implementing the Recyclerview, we add the Adapter.

Here we implement the home screen recycler view adapter named “DailyCakeListScrollAdapter” and for the menu item.

class DailyCakeListScrollAdapter(

var categoryMenuItemList1: List<String>

) : RecyclerView.Adapter<FirstViewHolderr>() {

override fun onCreateViewHolder(viewGroup: ViewGroup, i: Int): FirstViewHolderr {

val v = LayoutInflater.from(viewGroup.context)

.inflate(R.layout.layout_menu_list, viewGroup, false)

return FirstViewHolderr(v)

}

override fun onBindViewHolder(firstViewHolder: FirstViewHolderr, i: Int) {

firstViewHolder.itemView.text_cake.text = categoryMenuItemList1[i]

firstViewHolder.itemView.textCount.text = "Pizza " + i + 1

}

override fun getItemCount(): Int {

return categoryMenuItemList1.size

}

inner class FirstViewHolderr(itemView: View) : RecyclerView.ViewHolder(itemView)

}

4.) Notify the XML part of this adapter named “layout_menu_list”

<?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"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginHorizontal="3dp"
    android:layout_marginBottom="10dp">

<androidx.cardview.widget.CardView
        android:id="@+id/card_image"
        android:layout_width="105sp"
        android:layout_height="105sp"
        app:cardCornerRadius="10dp"
        android:layout_margin="3dp"
        app:cardElevation="5dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

<androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

</androidx.constraintlayout.widget.ConstraintLayout>
    </androidx.cardview.widget.CardView>

</androidx.constraintlayout.widget.ConstraintLayout>

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<?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"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginHorizontal="3dp"

android:layout_marginBottom="10dp">

<androidx.cardview.widget.CardView

android:id="@+id/card_image"

android:layout_width="105sp"

android:layout_height="105sp"

app:cardCornerRadius="10dp"

android:layout_margin="3dp"

app:cardElevation="5dp"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toTopOf="parent">

<androidx.constraintlayout.widget.ConstraintLayout

android:layout_width="match_parent"

android:layout_height="match_parent">

<ImageView

android:id="@+id/image_cake"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:gravity="start"

android:scaleType="centerCrop"

android:src="@drawable/ic_launcher_background"

android:textAlignment="viewStart"

app:layout_constraintHorizontal_bias="0.0"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

</androidx.cardview.widget.CardView>

<TextView

android:id="@+id/text_cake"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_marginStart="7.8dp"

android:layout_marginLeft="7.8dp"

android:layout_marginTop="5dp"

android:gravity="start"

android:text="Pizza Hut"

android:textAlignment="viewStart"

android:textColor="@color/black"

android:textSize="17sp"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toEndOf="@id/card_image"

app:layout_constraintTop_toTopOf="parent" />

<TextView

android:id="@+id/textCount"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:layout_marginStart="7.8dp"

android:layout_marginEnd="14dp"

android:layout_marginTop="4dp"

android:paddingBottom="5dp"

android:gravity="start"

android:minLines="2"

android:maxLines="4"

android:text="Pizza"

android:textAlignment="viewStart"

android:textColor="@color/black"

android:textSize="14sp"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintStart_toEndOf="@id/card_image"

app:layout_constraintTop_toBottomOf="@id/text_cake"

app:layout_constraintVertical_bias="0.0"

android:layout_marginLeft="7.8dp"

android:layout_marginRight="14dp" />

<TextView

android:id="@+id/text_cakePrice"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginStart="6dp"

android:layout_marginVertical="8dp"

android:layout_marginEnd="14dp"

android:gravity="start"

android:textAlignment="viewStart"

android:textColor="@color/black"

android:text="20.00"

android:textSize="15sp"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintTop_toBottomOf="@id/textCount"

android:layout_marginLeft="6dp"

android:layout_marginRight="14dp" />

<TextView

android:id="@+id/text_cakeOfferPrice"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginStart="6dp"

android:layout_marginVertical="8dp"

android:layout_marginEnd="14dp"

android:gravity="start"

android:text="price"

android:textAlignment="viewStart"

android:textColor="@color/black"

android:textSize="15sp"

app:layout_constraintBottom_toBottomOf="parent"

app:layout_constraintEnd_toStartOf="@id/text_cakePrice"

app:layout_constraintTop_toBottomOf="@id/textCount"

android:layout_marginLeft="6dp"

android:layout_marginRight="14dp" />

</androidx.constraintlayout.widget.ConstraintLayout>

5.) For the menu, item listing add the recycler adapter for the “MenuListAdapter”

class MenuListAdapter(
    private val categoryMenuItemList: List<String>,
    private val listener: OnItemClickListener
) : RecyclerView.Adapter<MenuListAdapter.ViewHolder>() {
    var flag = false
    var positionSelected = 0

interface OnItemClickListener {
        fun onItemClick(position: Int, check: Boolean)
    }

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

override fun onBindViewHolder(viewHolder: ViewHolder, position: Int) {
        viewHolder.itemView.menu_name.text = categoryMenuItemList[position]
        flag = if (positionSelected == position) {
            viewHolder.itemView.menu_name.setTextColor(Color.parseColor("#D1007E"))
            viewHolder.itemView.text_menu_counts.setTextColor(Color.parseColor("#D1007E"))
            false
        } else {
            viewHolder.itemView.menu_name.setTextColor(Color.parseColor("#000000"))
            viewHolder.itemView.text_menu_counts.setTextColor(Color.parseColor("#000000"))
            true
        }
    }

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

inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        init {
            itemView.setOnClickListener {
                positionSelected = adapterPosition
                notifyDataSetChanged()
                listener.onItemClick(positionSelected, true)
            }
        }
    }
}

class MenuListAdapter(

private val categoryMenuItemList: List<String>,

private val listener: OnItemClickListener

) : RecyclerView.Adapter<MenuListAdapter.ViewHolder>() {

var flag = false

var positionSelected = 0

interface OnItemClickListener {

fun onItemClick(position: Int, check: Boolean)

}

override fun onCreateViewHolder(viewGroup: ViewGroup, i: Int): ViewHolder {

val v = LayoutInflater.from(viewGroup.context).inflate(R.layout.item_menu, viewGroup, false)

return ViewHolder(v)

}

override fun onBindViewHolder(viewHolder: ViewHolder, position: Int) {

viewHolder.itemView.menu_name.text = categoryMenuItemList[position]

flag = if (positionSelected == position) {

viewHolder.itemView.menu_name.setTextColor(Color.parseColor("#D1007E"))

viewHolder.itemView.text_menu_counts.setTextColor(Color.parseColor("#D1007E"))

false

} else {

viewHolder.itemView.menu_name.setTextColor(Color.parseColor("#000000"))

viewHolder.itemView.text_menu_counts.setTextColor(Color.parseColor("#000000"))

true

}

override fun getItemCount(): Int {

return categoryMenuItemList.size

}

inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {

init {

itemView.setOnClickListener {

positionSelected = adapterPosition

notifyDataSetChanged()

listener.onItemClick(positionSelected, true)

}

You can refer to this screenshot for the menu list view in the application. How it looks like

6.) The last UI of the mentioned Menu screen is added below

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingBottom="20dp"
    xmlns:app="http://schemas.android.com/apk/res-auto">

</androidx.constraintlayout.widget.ConstraintLayout>

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

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:paddingBottom="20dp"

xmlns:app="http://schemas.android.com/apk/res-auto">

<TextView

android:id="@+id/menu_name"

android:layout_width="0dp"

android:layout_height="wrap_content"

android:gravity="start"

android:textAlignment="viewStart"

android:text=""

android:textColor="@color/black"

android:textSize="17sp"

app:layout_constraintEnd_toStartOf="@id/text_menu_counts"

app:layout_constraintHorizontal_bias="0.0"

app:layout_constraintStart_toStartOf="parent"

app:layout_constraintTop_toTopOf="parent" />

<TextView

android:id="@+id/text_menu_counts"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:gravity="start"

android:text=""

android:textColor="@color/black"

android:textAlignment="viewStart"

android:textSize="17sp"

android:focusable="false"

app:layout_constraintEnd_toEndOf="parent"

app:layout_constraintHorizontal_bias="0.0"

app:layout_constraintStart_toEndOf="@id/menu_name"

app:layout_constraintTop_toTopOf="@id/menu_name"

app:layout_constraintBottom_toBottomOf="@id/menu_name"/>

</androidx.constraintlayout.widget.ConstraintLayout>

Finally, we implemented the code part of the scrolling view Recycler in this blog.

Also, we use the base class for smooth scrolling. Handles basic tracking of the target view position and provides methods to trigger a programmatic scroll.

An instance of SmoothScroller is only intended to be used once. You should create a new instance for each call to LayoutManager#startSmoothScroll(SmoothScroller)

You can also check these links.

https://mobikul.com/adding-fast-scroller-recyclerview/

Another mentioned URL

I hope this blog will help you to how to Scroll RecyclerView to show the selected items on top.

For more understanding please can go through this link. That’s all, You can enjoy your recycler view scrolling feature. Thank you very much.