java.lang.IllegalStateException при создании фрагмента в DialogFragment

При попытке создать фрагмент внутри DialogFragment приложение вылетает, а в стэктрэйсе такое описание проблемы:

java.lang.IllegalStateException: Fragment does not have a view                                          
at android.support.v4.app.Fragment$2.onFindViewById(Fragment.java:2203)                             
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1316)                
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1574)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1641)                
at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:794)                      
at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2415)                 
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2200)         
at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2153)      
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2063)         
at android.support.v4.app.Fragment.performStart(Fragment.java:2261)                                 
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1369)                
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1574)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1641)                
at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:794)                      
at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2415)                 
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2200)         
at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2153)      
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2063)         
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:725)                       
at android.os.Handler.handleCallback(Handler.java:739)                                              
at android.os.Handler.dispatchMessage(Handler.java:95)                                              
at android.os.Looper.loop(Looper.java:148)                                                          
at android.app.ActivityThread.main(ActivityThread.java:5417)                                        
at java.lang.reflect.Method.invoke(Native Method)                                                   
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)                  
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)         

В самом DialogFragment такой код:

public class TestFragment extends DialogFragment {
static AppCompatActivity activity;
static TextView mMainWord;
static int rightAnswer;
static FragmentManager fragmentManager;
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    View v = LayoutInflater.from(getActivity())
            .inflate(R.layout.fragment_test, null);
    mMainWord = v.findViewById(R.id.guess_word);
    mMainWord.setTextSize(45.f);
    activity = (AppCompatActivity) getActivity();
    fragmentManager = getChildFragmentManager();
    updateQuestion();
    return new AlertDialog.Builder(getActivity())
            .setView(v)
            .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialogInterface, int i) {}
            })
            .create();
}
public static void returnAnswer(int answer){
    mMainWord.setBackgroundColor(answer == rightAnswer? Color.GREEN : Color.RED);
    NextSubFragment fragment = NextSubFragment.newInstance();
    fragmentManager.beginTransaction().replace(R.id.sub_container, fragment).commit();
}
public static void updateQuestion(){
    CardLab mCardLab = CardLab.getCardLab(activity);
    if (!(mCardLab.getLength() < 4)) {
        List<Integer> indexes = newInt(new ArrayList<Integer>(), mCardLab.getLength());
        for (int i = 0; i <  3; i++) {
            newInt(indexes,  mCardLab.getLength());
        }
        List<CardLab.Card> list = mCardLab.getItems();
        String[] arr = new String[]{
                list.get(indexes.get(0)).getName(),
                list.get(indexes.get(1)).getName(),
                list.get(indexes.get(2)).getName(),
                list.get(indexes.get(3)).getName()};
        Random r = new Random();
        rightAnswer = r.nextInt(3);
        String mainWord = list.get(r.nextInt(3)).getTranslate();
        ChooseSubFragment subfragment = ChooseSubFragment.newInstance(arr);
        Log.w("test", subfragment == null ? "null" : "not null");
        fragmentManager.beginTransaction().replace(R.id.container ,subfragment ).commit();
        mMainWord.setText(mainWord);
    } else {
        mMainWord.setTextSize(15.f);
        mMainWord.setText(R.string.not_enouhg_cards_err);
    }
}
private static List<Integer> newInt(List<Integer> list, int max){
    Integer i;
    Random r = new Random();
    i = r.nextInt(max);
    if (!list.contains(i)) {
        list.add(i);
        return list;
    } else {
        return newInt(list, max);
    }
}

}

А так же код вызываемого фрагмента:

public class ChooseSubFragment extends Fragment{
static List<Button> chooseButtons;
static List<String> variants;
static List<View.OnClickListener> listeners;
public ChooseSubFragment() {
}
public static ChooseSubFragment newInstance(final String [] variantsArr) {
    ChooseSubFragment fragment = new ChooseSubFragment();
    variants = new ArrayList<>();
    listeners = new ArrayList<>();
    for (int i = 0; i < 4; i++) {
        variants.add(variantsArr[i]);
        final int j = i;
        listeners.add(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                TestFragment.returnAnswer(j);
            }
        });
    }
    return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.subfragment_choose, container, false);
    chooseButtons = new ArrayList<>();
    Button button;
    button = view.findViewById(R.id.choose_first);
    chooseButtons.add(button);
    button = view.findViewById(R.id.choose_second);
    chooseButtons.add(button);
    button = view.findViewById(R.id.choose_third);
    chooseButtons.add(button);
    button = view.findViewById(R.id.choose_fourth);
    chooseButtons.add(button);
    Log.w("test", chooseButtons.get(0) == null ? "null" : "not null");
    for (int i = 0; i < chooseButtons.size(); i++) {
        chooseButtons.get(i).setText(variants.get(i));
        chooseButtons.get(i).setOnClickListener(listeners.get(i));
    }
    return view;
}

}

Подскажите, как решить проблему.