How to scroll RecyclerView (Page up and down) programmatically from your Android App?

In this video it shows how to use ScrollBy API of RecyclerView to scroll the pages in recycler view programmatically from your Android App’s code.

To build the recycler view it re-uses the part of code previously published in our below page:
https://programmerworld.co/android/how-to-show-images-in-recycler-view-in-your-android-app/

I hope you like this video. For any questions, suggestions or appreciation please contact us at: https://programmerworld.co/contact/ or email at: programmerworld1990@gmail.com

Complete source code and other details:

package com.programmerworld.scrollrecyclerview;

import static android.Manifest.permission.READ_MEDIA_IMAGES;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.storage.StorageManager;
import android.os.storage.StorageVolume;
import android.view.View;

import java.io.File;

public class MainActivity extends AppCompatActivity {

    private RecyclerView recyclerView;
    private RecyclerView.LayoutManager layoutManagerRecyclerView;
    private RecyclerViewCustomAdapter recyclerViewCustomAdapter;

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

        ActivityCompat.requestPermissions(this,
                new String[]{READ_MEDIA_IMAGES},
                PackageManager.PERMISSION_GRANTED);

        recyclerView = findViewById(R.id.recyclerView);
        // Liner Layout
        layoutManagerRecyclerView = new LinearLayoutManager(MainActivity.this);
        // GRID Layout
        //layoutManagerRecyclerView = new GridLayoutManager(MainActivity.this, 2);
        recyclerView.setLayoutManager(layoutManagerRecyclerView);
        StorageManager storageManager = (StorageManager) getSystemService(STORAGE_SERVICE);
        StorageVolume storageVolume = storageManager.getStorageVolumes().get(0); // internal memory/ storage

        File fileImage = new File(storageVolume.getDirectory().getPath() + "/Download/images.jpeg");
        File fileImage1 = new File(storageVolume.getDirectory().getPath() + "/Download/images1.jpeg");

        Bitmap bitmap = BitmapFactory.decodeFile(fileImage.getPath());
        Bitmap bitmap1 = BitmapFactory.decodeFile(fileImage1.getPath());

        Bitmap[] bitmaps = {bitmap, bitmap1};
        recyclerViewCustomAdapter = new RecyclerViewCustomAdapter(bitmaps);
        recyclerView.setAdapter(recyclerViewCustomAdapter);
    }

    public void buttonScrollDown(View view){
        recyclerView.scrollBy(0, recyclerView.getWidth());
    }

    public void buttonScrollUp(View view){
        recyclerView.scrollBy(0, -recyclerView.getWidth());
    }
}

package com.programmerworld.scrollrecyclerview;

import android.graphics.Bitmap;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

public class RecyclerViewCustomAdapter extends RecyclerView.Adapter<RecyclerViewCustomAdapter.ViewHolder> {
    private Bitmap[] bitmapsLocal;
    public RecyclerViewCustomAdapter(Bitmap[] bitmaps) {
        bitmapsLocal = bitmaps;
    }
    public static class ViewHolder extends  RecyclerView.ViewHolder{
        private final ImageView imageView;
        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            imageView = itemView.findViewById(R.id.imageView);
        }
        public ImageView getImageView(){
            return imageView;
        }
    }

    @NonNull
    @Override
    public RecyclerViewCustomAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.images_row_items,
                        parent,
                        false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerViewCustomAdapter.ViewHolder holder, int position) {
        holder.getImageView().setImageBitmap(bitmapsLocal[position]);
    }

    @Override
    public int getItemCount() {
        return bitmapsLocal.length;
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <uses-permission android:name="android.permission.READ_MEDIA_IMAGES"/>

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/Theme.ScrollRecyclerView"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

<?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=".MainActivity">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="232dp"
        android:layout_marginTop="92dp"
        android:onClick="buttonScrollDown"
        android:text="Scroll Down"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="286dp"
        android:layout_height="487dp"
        android:layout_marginStart="60dp"
        android:layout_marginTop="27dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button2" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="47dp"
        android:layout_marginTop="100dp"
        android:onClick="buttonScrollUp"
        android:text="Scroll Up"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

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

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/ic_launcher_background" />
</FrameLayout>