public class PunjabiSingleTracks extends Fragment {
RecyclerView rvImageList;
DatabaseReference databaseList, databaseDownload;
DownloadManager downloadManager;
private AnimationDrawable animationDrawable;
private ImageView mProgressBar;
FloatingActionButton fab;
NotificationManager notificationManager;
private int STORAGE_PERMISSION_CODE = 1;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.punjabisingletracks, container, false);
    rvImageList = (RecyclerView) rootView.findViewById(R.id.rvImagelist);
    rvImageList.setHasFixedSize(true);
    mProgressBar = (ImageView) rootView.findViewById(R.id.main_progress);
    fab = (FloatingActionButton) rootView.findViewById(R.id.fabpunjabisingletracks);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent(getActivity(), Search_PunjabiSingleTracks.class);
            startActivity(intent);
        }
    });
    LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
    rvImageList.setLayoutManager(new LinearLayoutManager(getActivity()));
    layoutManager.setReverseLayout(true);
    layoutManager.setStackFromEnd(true);
    rvImageList.setLayoutManager(layoutManager);
    rvImageList.addOnScrollListener(new RecyclerView.OnScrollListener() {

        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {

            if (dy > 0) {
                if (recyclerView.canScrollVertically(RecyclerView.FOCUS_DOWN) == false) {
                    Toast.makeText(getActivity(), "No More", Toast.LENGTH_SHORT).show();
                }

            }
        }
    });
    databaseList = FirebaseDatabase.getInstance().getReference().child("punjabisingletracks");
    databaseList.keepSynced(true);
    databaseDownload = FirebaseDatabase.getInstance().getReference().child("punjabisingletracks");
    databaseDownload.keepSynced(true);
    mProgressBar.setBackgroundResource(R.drawable.spinner);
    animationDrawable = (AnimationDrawable) mProgressBar.getBackground();
    mProgressBar.setVisibility(View.VISIBLE);
    animationDrawable.start();
    return rootView;
 }
public void onStart(){
    super.onStart();

    FirebaseRecyclerAdapter<PunjabiSingleTracks_List, UploadImageHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<PunjabiSingleTracks_List, UploadImageHolder>(
            PunjabiSingleTracks_List.class,
            R.layout.punjabisonglist,
            UploadImageHolder.class,
            databaseList
) {
   @Override
        protected void populateViewHolder(UploadImageHolder viewHolder,
  PunjabiSingleTracks_List model, int position) {
            final String Image_Key=getRef(position).getKey();
   viewHolder.setDetails(getActivity(), model.getTitle(),
  model.getDesc(), model.getImage());
            mProgressBar.setVisibility(View.GONE);
            animationDrawable.stop();
 viewHolder.txttwo.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View view) {

                    databaseDownload.addListenerForSingleValueEvent(new ValueEventListener() {

                        @Override
                        public void onDataChange(DataSnapshot dataSnapshot) {
                            String ImageUrl = dataSnapshot.child(Image_Key).child("two").getValue(String.class);

                            downloadManager = (DownloadManager)getActivity().getSystemService(Context.DOWNLOAD_SERVICE);
                            Uri uri = Uri.parse(ImageUrl);
                            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {

                                try {ConnectivityManager connMgr = (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
                                    NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
                                    if (networkInfo != null && networkInfo.isConnected()) {
                                        DownloadManager.Request request = new DownloadManager.Request(uri);
                                        String fileName = ImageUrl.substring(ImageUrl.lastIndexOf('/') + 1);
                                        request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, fileName);
                                        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
                                        Toast.makeText(getActivity(), "Downloading File", Toast.LENGTH_SHORT).show();
                                        downloadManager.enqueue(request);

                                    }else {
                                        AlertDialog alertDialog;
                                        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
                                        builder.setMessage("You need a network connection to download the song. Please turn on mobile network or Wi-Fi in Settings.")
                                                .setNegativeButton("OK", new DialogInterface.OnClickListener() {
                                                            @Override
                                                            public void onClick(DialogInterface dialog, int which) {
                                                                dialog.cancel();
                                                            }
                                                        }
                                                )
                                                .setCancelable(false);
                                                /* .setCancelable(false)
                                                /.setPositiveButton("WIFI", new DialogInterface.OnClickListener() {
                                                    @Override
                                                    public void onClick(DialogInterface dialog, int which) {
                                                        startActivity(new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS));

                                                    }
                                                });*/
                                        alertDialog = builder.create();
                                        alertDialog.show();
                                        //Toast.makeText(getActivity(),"Pleae check your internet connection",Toast.LENGTH_SHORT).show();
                                    }
                                }catch (Exception e){
                                    requestStoragePermission();
                                }

                            } else {
                                Intent i = new Intent(Intent.ACTION_VIEW);
                                i.setData(Uri.parse(ImageUrl));
                                startActivity(i);
                            }
                        }

                        @Override
                        public void onCancelled(DatabaseError databaseError) {

                        }
                    });
    rvImageList.setAdapter(firebaseRecyclerAdapter);

}

public static class UploadImageHolder extends RecyclerView.ViewHolder{

    View view;
    TextView txttwo;
    public UploadImageHolder(View itemView) {
        super(itemView);
        view = itemView;
        txttwo = (TextView)view.findViewById(R.id.twokbps);
    }
    public void setDetails(Context ctx, String title, String desc, String image){

        TextView imagetitle = (TextView) view.findViewById(R.id.tvuserimagetitle);
        TextView imagedesc = (TextView) view.findViewById(R.id.tvuserimagedesc);
        ImageView imageView = (ImageView) view.findViewById(R.id.UserImage);


        imagetitle.setText(title);
        imagedesc.setText(desc);

        Picasso.with(ctx).load(image).into(imageView);
     }