Nullpointerexception on button inside include

Question

I have a button that advances a viewpager, but I did it inside a include, because I use on several screen, but when I try to click on it it me error Nullpointerexception, I have checked the ids, if it has repeated but apparently ta everything ok.

My XML:

    <?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/dia1s2layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/imageView6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="64dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@mipmap/ic_launcher_round" />

    <TextView
        android:id="@+id/textView9"
        android:layout_width="0dp"
        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="Pesquise qualquer palavra que não compreenda."
        android:textAlignment="center"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView6"
        app:layout_constraintVertical_bias="0.0" />

    <TextView
        android:id="@+id/textView15"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:text="Evite o máximo o uso da tradução"
        android:textAlignment="center"
        android:textSize="18sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView9" />

    <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" />
</android.support.constraint.ConstraintLayout>

public class DiaFragment extends Fragment {
    private static final String TAG = "igr";
    private CustomViewPager viewPager;
    private PlayPauseView btn_audio;
    private FancyButton btn_prox;
    int posicaolayoutaudio;
    private int[] mlayouts;
    private int[] mlayoutslayout;
    int layoutaudioposicao;
    private ViewGroup containerdia;
    private boolean finalizar;

    public DiaFragment() {
    }

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

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

        viewPager = view.findViewById(R.id.viewpagerdias);
        viewPager.setPagingEnabled(false);
        viewPager.setAdapter(new PagerAdapter() {
            @Override
            public Object instantiateItem(ViewGroup container, int position) {
                int resId;
                View view;
                LayoutInflater inflater = (LayoutInflater) container.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                resId = mlayouts[position];
                view = inflater.inflate(resId, null);

                //botão proximo
                View myLayout = view.findViewById( mlayoutslayout[position] );
                btn_prox = myLayout.findViewById(R.id.btn_prox);
                btn_prox.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        mudarpagina();
                    }
                });

                //botao audio
                View includeaudio = view.findViewById(R.id.includeaudio);
                if (includeaudio != null){
                    btn_audio = myLayout.findViewById(R.id.btn_audio);
                    btn_audio.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            Toast.makeText(getContext(), "audio", Toast.LENGTH_SHORT).show();
                        }
                    });
                }
                container.addView(view);
                return view;
            }
            @Override
            public int getCount() {
                return mlayouts.length;
            }
            @Override
            public void destroyItem(ViewGroup container, int position, Object object) {
                container.removeView((View)object);
            }
            @Override
            public boolean isViewFromObject(View view, Object object) {
                return view == object;
            }
        });
        viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }
            @Override
            public void onPageSelected(int position) {
                if (position == mlayouts.length-1) {
                    btn_prox.setText(getString(R.string.terminar));
                    btn_prox.setIconResource("");
                    btn_prox.setBackgroundColor(Color.parseColor("#3b5998"));
                    finalizar = true;
               }
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });
    }

    private void mudarpagina() {
        if (finalizar){
            Log.d(TAG, "onClick: Entrou no finalizar");
            Fragment fragment = new PreparacaoFragment();
            FragmentTransaction ft = getFragmentManager().beginTransaction();
            ft.replace(R.id.contentmain, fragment);
            ft.commit();
        }else if (viewPager.getCurrentItem()  != mlayouts.length){
            viewPager.setCurrentItem(viewPager.getCurrentItem()+1);
        }

    }
}

Here I pass the layout as arguments pro Fragment:

@Override
public void onClick(View view) {
    switch (view.getId()){
        case R.id.btndia1:
            FragmentTransaction ft = getFragmentManager().beginTransaction();
            DiaFragment fragmentdiapreparacao = new DiaFragment();

            Bundle args = new Bundle();
            //SETAR LAYOUTS
            int[] layouts = {R.layout.dia1s1, R.layout.dia1s2, R.layout.dias1s3};
            args.putIntArray("layouts",layouts);
            int[] layoutslayout = {R.id.dia1s1layout, R.id.dia1s2layout, R.id.dia1s3layout};
            args.putIntArray("layoutslayout",layoutslayout);
            //PASSAR LAYOUT QUE CONTEM AUDIO [ POSICAO ]
            args.putInt("layoutaudioposicao",3);
            fragmentdiapreparacao.setArguments(args);
            ft.replace(R.id.contentmain, fragmentdiapreparacao);
            ft.commit();
            break;
    }
}

Stacktrace:

12-18 14:25:18.511 23084-23084/doupenglish.com.br.doup E/AndroidRuntime: FATAL EXCEPTION: main
                                                                     Process: doupenglish.com.br.doup, PID: 23084
                                                                     java.lang.NullPointerException: Attempt to invoke virtual method 'void mehdi.sakout.fancybuttons.FancyButton.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
                                                                         at doupenglish.com.br.doup.Fragments.DiaFragment$1.instantiateItem(DiaFragment.java:72)
                                                                         at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:1002)
                                                                         at android.support.v4.view.ViewPager.populate(ViewPager.java:1216)
                                                                         at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:662)
                                                                         at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:624)
                                                                         at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:605)
                                                                         at doupenglish.com.br.doup.Fragments.DiaFragment.mudarpagina(DiaFragment.java:165)
                                                                         at doupenglish.com.br.doup.Fragments.DiaFragment.access$300(DiaFragment.java:26)
                                                                         at doupenglish.com.br.doup.Fragments.DiaFragment$1$1.onClick(DiaFragment.java:75)
                                                                         at android.view.View.performClick(View.java:5637)
                                                                         at android.view.View$PerformClick.run(View.java:22433)
                                                                         at android.os.Handler.handleCallback(Handler.java:751)
                                                                         at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                         at android.os.Looper.loop(Looper.java:153)
                                                                         at android.app.ActivityThread.main(ActivityThread.java:6244)
                                                                         at java.lang.reflect.Method.invoke(Native Method)
                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:891)
                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:781)

I realized that only occurs the error, when I pass a third layout for arguments to Fragment, before I was passing only the first two.

 case R.id.btndia1:
            FragmentTransaction ft = getFragmentManager().beginTransaction();
            DiaFragment fragmentdiapreparacao = new DiaFragment();

            Bundle args = new Bundle();
            //SETAR LAYOUTS
            int[] layouts = {R.layout.dia1s1, R.layout.dia1s2,R.layout.dias1s3};
            args.putIntArray("layouts",layouts);
            int[] layoutslayout = {R.id.dia1s1layout, R.id.dia1s2layout,R.id.dia1s3layout};
            args.putIntArray("layoutslayout",layoutslayout);
            //PASSAR LAYOUT QUE CONTEM AUDIO [ POSICAO ]
            //args.putInt("layoutaudioposicao",3);
            fragmentdiapreparacao.setArguments(args);
            ft.replace(R.id.contentmain, fragmentdiapreparacao);
            ft.commit();
            break;
    }

If you need more code, just ask

Answer 1

I managed to solve, just to take the id of the include

Answer 2

No need to specify include within xml try this way.

//botão proximo
//View myLayout = view.findViewById( mlayoutslayout[position] );
btn_prox = view.findViewById(R.id.btn_prox);
btn_prox.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        mudarpagina();
    }
});

I hope it helps you.