How to show total number of recyclerview in a textview in android studio

I have data on firebase, the data is shown in recyclerview. I have so many recyclerviews showing. Above a recyclerview I have a textview where I want to show the total number of recyclerviews. I have also a button so that when I click on it does the count and show the result in a textview. In summary: If i click a button i want to see the number of recyclerviews in a textview.

Here is my .xml code:

 <RelativeLayout
            android:id="@+id/rlRunning"
            android:background="#00ff0000"
            android:layout_below="@+id/rl"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/del_t"
                android:text="mmmm"
                android:textSize="30sp"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />
            <Button
                android:onClick="clickMe"
                android:id="@+id/btn_t"
                android:layout_below="@+id/del_t"
                android:text="Click me"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />

            <android.support.v7.widget.RecyclerView
                android:layout_below="@+id/btn_t"
                android:id="@+id/recyclerview"
                android:background="#00ff0000"
                android:layout_width="match_parent"
                android:layout_height="match_parent">
            </android.support.v7.widget.RecyclerView>
        </RelativeLayout>

Here is my adapter:

public class BlogzoneImages {

    private String ititle, idate, idesc,imageUrl;

    public BlogzoneImages(String ititle, String idate, String imageUrl, String idesc ) {
        this.idate = idate;
        this.ititle = ititle;
        this.idesc = idesc;
        this.imageUrl=imageUrl;
    }

    public BlogzoneImages() {
    }

    public void setImageUrl(String imageUrl) {
        this.imageUrl = imageUrl;
    }

    public void setiDate(String idate) {
        this.idate = idate;
    }

    public void setiTitle(String ititle) {
        this.ititle = ititle;
    }

    public void setiDesc(String idesc) {
        this.idesc = idesc;
    }

    public String getImageUrl() {
        return imageUrl;
    }

    public String getiDate() {
        return idate;
    }

    public String getiTitle() {
        return ititle;
    }

    public String getiDesc() {
        return idesc;
    }
}

Here is how I am getting the data to display in MainActivity.java

protected void loadImage_setups() {
        mAuth.addAuthStateListener(mAuthListener);
        FirebaseRecyclerAdapter<BlogzoneImages, BlogzoneViewHolder2> FBRA_Images = new FirebaseRecyclerAdapter<BlogzoneImages, BlogzoneViewHolder2>(
                BlogzoneImages.class,
                R.layout.setups_card,
                BlogzoneViewHolder2.class,
                image_Database

        ) {
            @Override
            protected void populateViewHolder(BlogzoneViewHolder2 viewHolder, BlogzoneImages model, int position) {
                final String post_key = getRef(position).getKey().toString();
                viewHolder.setiDate(model.getiDate());
                viewHolder.setiTitle(model.getiTitle());
                viewHolder.setiDesc(model.getiDesc());
                viewHolder.setImageUrl(getApplicationContext(), model.getImageUrl());
                viewHolder.mView2.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        //   Intent singleActivity = new Intent(MainActivity.this, SinglePostActivity.class);
                        //   singleActivity.putExtra("PostID", post_key);
                        //   startActivity(singleActivity);
                    }
                });
            }
        };
        recyclerView.setAdapter(FBRA_Images);
    }

    public static class BlogzoneViewHolder2 extends RecyclerView.ViewHolder {
        View mView2;

        public BlogzoneViewHolder2(View itemView2) {
            super(itemView2);
            mView2 = itemView2;
        }

        public void setiDate(String idate) {
            TextView post_date = mView2.findViewById(R.id.setup_date);
            post_date.setText(idate);
        }

        public void setiTitle(String ititle) {
            TextView post_title = mView2.findViewById(R.id.setup_title);
            post_title.setText(ititle);
        }

        public void setiDesc(String idesc) {
            TextView post_desc = mView2.findViewById(R.id.setup_desc);
            post_desc.setText(idesc);
        }

        public void setImageUrl(Context ctx, String imageUrl) {
            ImageView post_image = mView2.findViewById(R.id.setup_image);
            Picasso.with(ctx).load(imageUrl).into(post_image);
        }
    }

All this is well, the data is showing nicely on recyclerview.

My worry now is to show the total number of these recyclerviews in a texview when i click the button.

I have tried this in MainActivity.java:

int count = 0;
    public void showTotal() {
        RecyclerView recyclerView = (RecyclerView)findViewById(R.id.recyclerview);
        if (recyclerView.getAdapter() != null) {
            count = recyclerView.getAdapter().getItemCount();
        }
        TextView tvvv = (TextView)findViewById(R.id.del_t);
        tvvv.setText(count);
    }
    public void clickMe(View view) {
        showTotal();
    }

When i click the button, the app crashes. I have also tried this:

public void showTotal() {
        RecyclerView recyclerView = (RecyclerView)findViewById(R.id.recyclerview);
        int itemCount = recyclerView.getAdapter().getItemCount();
        TextView tvvv = (TextView)findViewById(R.id.del_t);
        tvvv.setText(itemCount);
    }
    public void clickMe(View view) {
        showTotal();
    }

When I click the button, the app crashes again. So now I am stuck. I have no idea how to solve this. My question is, how can i show the total number of recyclerviews in a TextView after a button click?