How to Build an Image Gallery Android App with RecyclerView and Glide?

 package com.example.piceditor;

import android.content.Context;
import android.text.Layout;
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;

import com.bumptech.glide.Glide;

import java.io.File;
import java.util.ArrayList;

public class GalleryAdapter extends RecyclerView.Adapter<GalleryAdapter.ViewHolder> {

    private Context context;
    private ArrayList<String> images_list;

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view= LayoutInflater.from(context).inflate(R.layout.gellary_item,null,true);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        File image_file=new File(images_list.get(position));
        if(image_file.exists()){
            Glide.with(context).load(image_file).into(holder.image);
        }
    }

    @Override
    public int getItemCount() {
        return images_list.size();
    }

    public GalleryAdapter(Context context, ArrayList<String> images_list) {
        this.context = context;
        this.images_list = images_list;
    }

    public class ViewHolder extends RecyclerView.ViewHolder{
        private ImageView image;
        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            image=itemView.findViewById(R.id.gallery_item);
        }
    }
}

package com.example.piceditor;

import static android.Manifest.permission.READ_EXTERNAL_STORAGE;
import static android.os.Environment.MEDIA_MOUNTED;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.content.pm.PackageManager;
import android.database.Cursor;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    static int PERMISSION_REQUEST_CODE=100;
    RecyclerView recyclerView;
    ArrayList<String> images;
    GalleryAdapter adapter;
    GridLayoutManager manager;

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

        recyclerView=findViewById(R.id.gallery_recycler);
        images=new ArrayList<>();
        adapter=new GalleryAdapter(this,images);
        manager=new GridLayoutManager(this,3);

        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(manager);
        checkPermissions();

    }

    private void checkPermissions() {
        int result= ContextCompat.checkSelfPermission(getApplicationContext(),READ_EXTERNAL_STORAGE);
    if(result== PackageManager.PERMISSION_GRANTED){
            loadImages();
        }else{
        ActivityCompat.requestPermissions(this,new String[]{READ_EXTERNAL_STORAGE},PERMISSION_REQUEST_CODE);
    }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if(grantResults.length > 0){
        boolean accepted=grantResults[0]==PackageManager.PERMISSION_GRANTED;
        if(accepted){
            loadImages();
        }else{
            Toast.makeText(this,"You have dined the permission",Toast.LENGTH_LONG).show();
        }
    }else{

    }
    }

    private void loadImages() {
        boolean SDCard= Environment.getExternalStorageState().equals(MEDIA_MOUNTED);
    if(SDCard){
        final String[] colums={MediaStore.Images.Media.DATA,MediaStore.Images.Media._ID};
        final String order=MediaStore.Images.Media.DATE_TAKEN+" DESC";
        Cursor cursor=getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,colums,null,null,order);
        int count =cursor.getCount();
        for(int i=0;i<count;i++){
            cursor.moveToPosition(i);
            int colunmindex=cursor.getColumnIndex(MediaStore.Images.Media.DATA);
            images.add(cursor.getString(colunmindex));
        }
        recyclerView.getAdapter().notifyDataSetChanged();
    }
    }
}