public ArrayList<String> getVideoFiles(String directoryPath) {
    ArrayList<String> result = new ArrayList<>();
    File directory = new File(directoryPath);
    File files[] = directory.listFiles(new FilenameFilter() {
        @Override
        public boolean accept(File dir, String name) {
            return name.endsWith(".MP4");
        }
    });

    for (File file : files) {
        result.add(file.getAbsoluteFile().toString());
    }

    return result;
}

@Override
    public void onBindViewHolder(VideoPreviewHolder holder, int position) {
        holder.mVideoPreviewImageView.setImageBitmap(mItems.get(position).getVideoBitmap());
        holder.mVideoPreviewTextView.setText(mItems.get(position).getVideoName());

        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                PreviewActivity previewActivity = new PreviewActivity();
                ArrayList<String> files = previewActivity
                        .getVideoFiles(Environment.getExternalStorageDirectory() + "/.OtherFile");

                Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(
                        String.valueOf(files)));
                intent.setDataAndType(Uri.parse(String.valueOf(Environment.getExternalStorageDirectory() + "/.OtherFile")), "video/MP4");
                v.getContext().startActivity(intent);

            }
        });
    }

public class VideoPreviewAdapter
        extends RecyclerView.Adapter<VideoPreviewAdapter.VideoPreviewHolder> {
    private Context mContext;
    private ArrayList<VideoPreview> mItems;
    private List<String> path_vid;

    public VideoPreviewAdapter(Context context) {
        mContext = context;
        mItems = new ArrayList<>();
    }

    public void addItems(ArrayList<VideoPreview> items) {
        mItems.addAll(items);
        notifyDataSetChanged();
    }

    public void clearItems() {
        mItems.clear();
    }

    @Override
    public VideoPreviewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater layoutInflater = LayoutInflater.from(mContext);
        View view = layoutInflater.inflate(R.layout.video_preview_item, parent, false);
        return new VideoPreviewHolder(view);
    }

   /* public void searchVid(File dir) {
        String pattern = ".MP4";
        //Get the listfile of that flder
        final File listFile[] = dir.listFiles();

        if (listFile != null) {
            for (int i = 0; i < listFile.length; i++) {
                final int x = i;
                if (listFile[i].isDirectory()) {
                    walkdir(listFile[i]);
                } else {
                    if (listFile[i].getName().endsWith(pattern)) {
                        // Do what ever u want, add the path of the video to the list
                        path_vid.add(listFile[i]);
                    }
                }
            }
        }
    }*/

    @Override
    public void onBindViewHolder(VideoPreviewHolder holder, int position) {
        holder.mVideoPreviewImageView.setImageBitmap(mItems.get(position).getVideoBitmap());
        holder.mVideoPreviewTextView.setText(mItems.get(position).getVideoName());

        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

               /* PreviewActivity previewActivity = new PreviewActivity();
                ArrayList<String> files = previewActivity
                        .getVideoFiles(Environment.getExternalStorageDirectory() + "/.OtherFile");
                for (String fileArray : files) {

                }*/
                String path = Environment.getExternalStorageDirectory() + "/.OtherFile";

                Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(String.valueOf(path)));

                intent.setDataAndType(Uri.parse(
                        String.valueOf(Environment.getExternalStorageDirectory() + "/.OtherFile")),
                        "video/MP4");
                v.getContext().startActivity(intent);

            }
        });
    }

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

    public class VideoPreviewHolder extends RecyclerView.ViewHolder {
        public ImageView mVideoPreviewImageView;
        public TextView mVideoPreviewTextView;

        public VideoPreviewHolder(View itemView) {
            super(itemView);
            mVideoPreviewImageView =
                    (ImageView) itemView.findViewById(R.id.video_preview_image_view);
            mVideoPreviewTextView = (TextView) itemView.findViewById(R.id.video_preview_text_view);
        }
    }
}

String strin = mItems.get(position).getVideoName();
                    File path_file = new File(Environment.getExternalStorageDirectory() + "/.OtherFile/" + strin);

                    Intent intent =
                            new Intent(Intent.ACTION_VIEW, Uri.parse(String.valueOf(path_file)));

                    intent.setDataAndType(Uri.parse(String.valueOf(path_file)), "video/mp4")
                    ;
                    v.getContext().startActivity(intent);