activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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=".MainActivity">

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:textSize="50sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <View
        android:id="@+id/bottom_bar"
        android:layout_width="0dp"
        android:layout_height="60dp"
        android:background="@android:color/holo_red_dark"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <android.support.v7.widget.RecyclerView
        android:id="@+id/page_carousel"
        android:layout_width="50dp"
        android:layout_height="50dp"
        app:layout_constraintBottom_toBottomOf="@id/bottom_bar"
        app:layout_constraintEnd_toEndOf="@id/bottom_bar"
        app:layout_constraintStart_toStartOf="@id/bottom_bar"
        app:layout_constraintTop_toTopOf="@id/bottom_bar"
        tools:listitem="@layout/item_pagecarousel" />

</android.support.constraint.ConstraintLayout>

CarouselDecorator.java

package shiro.am.i.sliderexample;

import android.content.Context;
import android.support.annotation.LayoutRes;
import android.support.annotation.NonNull;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.LinearSnapHelper;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class CarouselDecorator {

    private final Context context;
    private final int itemLayout;
    private final Adapter adapter;
    private final LinearLayoutManager layoutManager;

    private int pageCount;
    private OnPageChangeListener onPageChangeListener;

    public CarouselDecorator(Context context, @LayoutRes int itemLayout) {
        this.context = context;
        this.itemLayout = itemLayout;
        adapter = new Adapter();
        layoutManager = new LinearLayoutManager(context);
        layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
    }

    public void setPageCount(int pageCount) {
        this.pageCount = pageCount;
        adapter.notifyDataSetChanged();
    }

    public void setCurrentPage(int page) {
        layoutManager.scrollToPosition(page - 1);
    }

    public void setOnPageChangeListener(OnPageChangeListener onPageChangeListener) {
        this.onPageChangeListener = onPageChangeListener;
    }

    public void decorate(RecyclerView recyclerView) {
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setAdapter(adapter);
        recyclerView.addOnScrollListener(new OnScrollListener());

        LinearSnapHelper snapHelper = new LinearSnapHelper();
        snapHelper.attachToRecyclerView(recyclerView);
    }

    private class OnScrollListener extends RecyclerView.OnScrollListener {

        @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            if (newState != RecyclerView.SCROLL_STATE_IDLE) return;

            int position = layoutManager.findFirstVisibleItemPosition();
            onPageChangeListener.onPageChange(position + 1);
        }
    }

    private class Adapter extends RecyclerView.Adapter<ViewHolder> {

        @NonNull
        @Override
        public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            LayoutInflater inflater = LayoutInflater.from(context);
            View view = inflater.inflate(itemLayout, parent, false);
            return new ViewHolder(view);
        }

        @Override
        public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
            holder.textView.setText(String.valueOf(position + 1));
        }

        @Override
        public int getItemCount() {
            return pageCount;
        }
    }

    private static class ViewHolder extends RecyclerView.ViewHolder {

        private final TextView textView;

        private ViewHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView;
        }
    }

    public interface OnPageChangeListener {
        void onPageChange(int page);
    }
}

item_pagecarousel.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView 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="@android:color/darker_gray"
    android:gravity="center"
    android:textSize="18sp"
    tools:text="1" />

MainActivity.java

package shiro.am.i.sliderexample;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    private TextView text;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        text = findViewById(R.id.text);

        RecyclerView pageCarousel = findViewById(R.id.page_carousel);
        pageCarousel.setHasFixedSize(true);

        CarouselDecorator decorator = new CarouselDecorator(this, R.layout.item_pagecarousel);
        decorator.setPageCount(5); // default 0
        decorator.setCurrentPage(1); // default 1
        decorator.setOnPageChangeListener(this::onPageChange); // will throw NPE if not set
        decorator.decorate(pageCarousel);
    }

    private void onPageChange(int page) {
        text.setText(String.valueOf(page));
    }
}