ViewPager with Fragments inside PopupWindow (or DialogFragment) - Error no view found for id for fragment

I found a way to my problem.

Here we go

First I used DialogFragment instead of PopupView.

So in my main activity, I only created a Button who calls my DialogFragment.

public class Activity_principal1 extends FragmentActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_principal1);

        Button abrir = (Button) findViewById(R.id.botao);
        abrir.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                new DialogFragmentWindow().show(getSupportFragmentManager(), "");
            }
        });
    }

}

My adapter still the same as the question.

And here is where the magic occurs.

public class DialogFragmentWindow extends DialogFragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.popup, container);

        ViewPager vp_contentAcoesMusculares_SequenciaExercicios = (ViewPager) view.findViewById(R.id.vp_contentAcoesMusculares_SequenciaExercicios);
        List fragments = getFragments();
        AcoesMuscularesAdapter ama = new AcoesMuscularesAdapter(getChildFragmentManager(), fragments);
        vp_contentAcoesMusculares_SequenciaExercicios.setAdapter(ama);

        getDialog().getWindow().requestFeature(Window.FEATURE_NO_TITLE);

        return view;
    }

    private List getFragments(){
        List fList = new ArrayList();
            fList.add(FragmentAcoesMusculares.newInstance("Fragment 1",1));
            fList.add(FragmentAcoesMusculares.newInstance("Fragment 2",2));
            fList.add(FragmentAcoesMusculares.newInstance("Fragment 3",3));
        return fList;
    }
}

The difference is the getChildFragmentManager(). This little piece of code saved my day.

The explanation to this is when I was using getSupportFragmentManager() and even indicating the view pager was in another Layout XML he thought being in the main Layout XML.

Now my app gets the child fragment so now he sees the ViewPager.

That's it.

Thanks, everyone.