How to get button that is inside include

I have a fragment, which contains a ViewPager that inflates 2 views for now, but will have a next button in all layouts so I made a separate file with this button, but I can not get it to make the listener click it , it always returns me null

My Fragment that has ViewPager:

package doupenglish.com.br.doup.Fragments;


import android.annotation.SuppressLint;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.constraint.ConstraintLayout;
import android.support.v4.app.Fragment;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

import doupenglish.com.br.doup.MainActivity;
import doupenglish.com.br.doup.R;
import mehdi.sakout.fancybuttons.FancyButton;

/**
 * A simple {@link Fragment} subclass.
 */
public class DiaFragment extends Fragment {

    private Button btnaudio;
    int posicaolayoutaudio;
    private int[] mlayouts;
    private int[] mlayoutslayout;
    int layoutaudioposicao;

    public DiaFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        mlayouts = getArguments().getIntArray("layouts");
        mlayoutslayout = getArguments().getIntArray("layoutslayout");
        layoutaudioposicao = getArguments().getInt("layoutaudioposicao");
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.dia1f, container, false);
    }

    @SuppressLint("ClickableViewAccessibility")
    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);


        ViewPager viewPager = view.findViewById(R.id.viewpagerdia1);
        viewPager.setAdapter(new PagerAdapter() {

            @Override
            public Object instantiateItem(ViewGroup container, int position) {
                LayoutInflater inflater = (LayoutInflater) container.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                //ViewGroup layout1 = (ViewGroup) inflater.inflate(layouts[position], container, false);
                int resId;
                View view = null;
                if (position == layoutaudioposicao){
                    resId = mlayouts[position];
                    view = inflater.inflate(resId, null);
                    ConstraintLayout layout = view.findViewById(mlayoutslayout[position]);
                    /*btnaudio = layout.findViewById(R.id.btn_audio);
                    btnaudio.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            Toast.makeText(getContext(), "aaa", Toast.LENGTH_SHORT).show();
                        }
                    });*/
                    container.addView(view, 0);
                }else{
                    resId = mlayouts[position];
                    view = inflater.inflate(resId, null);
                    View btn_proxlayout = inflater.inflate(R.layout.btnprox,null);
                    FancyButton btn_prox = btn_proxlayout.findViewById(R.id.btn_prox);
                    btn_prox.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            Toast.makeText(getContext(), "aaa", Toast.LENGTH_SHORT).show();
                        }
                    });
                    container.addView(view, 0);
                }

                return view;
            }

            @Override
            public void destroyItem(ViewGroup container, int position, Object object) {
                container.removeView((View)object);
            }

            @Override
            public int getCount() {
                return mlayouts.length;
            }

            @Override
            public boolean isViewFromObject(View view, Object object) {
                return view == object;
            }
        });
        viewPager.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View view, MotionEvent motionEvent) {
                return false;
            }
        });






    }
}

My XML:

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

<TextView
    android:id="@+id/textView13"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="64dp"
    android:fontFamily="@font/scada"
    android:text="Investigue a unidade"
    android:textSize="30sp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/imageView4"
    app:layout_constraintVertical_bias="0.0" />

<ImageView
    android:id="@+id/imageView4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="64dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.0"
    app:srcCompat="@mipmap/ic_launcher_round" />

<TextView
    android:id="@+id/textView14"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="16dp"
    android:text="Utilize as imagens para auxiliar no entendimento do contexto do diálogo"
    android:textAlignment="center"
    android:textSize="18sp"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView13" />

<include
    layout="@layout/btnprox"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent" />

If you need more code just ask.