public class BingoAddNewFragment extends Fragment {

private static final String LOG_TAG = BingoDataManager.class.getSimpleName();

View v;

public static final String DEFAULT_EDIT_FRAGMENT_TAG = "editFragmentTag";


private Button mConfirmButton;
EditText mAddWords;

String newWord;

String bWord1 = "";
String bWord2 = "";
String bWord3 = "";
String bWord4= "";
String bWord5= "";
String bWord6= "";
String bWord7= "";
String bWord8= "";
String bWord9= "";
String bWord10= "";
String bWord11= "";
String bWord12= "";
String bWord13= "";
String bWord14= "";
String bWord15= "";
String bWord16= "";

String[] bWord = {bWord1, bWord2, bWord3, bWord4, bWord5, bWord6, bWord7, bWord8, bWord9,
        bWord10, bWord11, bWord12, bWord13, bWord14, bWord15, bWord16};


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}

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

    //some other stuff

    mConfirmButton = v.findViewById(R.id.button_confirm);

    mAddWords = v.findViewById(R.id.editText_addWords);

    mConfirmButton.setOnClickListener (new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            //The next line is not working (everything else seems fine) ->
            newWord = mAddWords.getText().toString();

            Log.d(LOG_TAG, "Begriff: " + newWord + " wird übergeben");
            saveWord (newWord);

        }
    });

    mSaveButton = v.findViewById(R.id.button_save_bingo);

    mSaveButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            saveBingo();
        }
    });


public String[] saveWord (String newWord) {

    Log.d(LOG_TAG, "Wort: " + newWord + " entgegengenommen.");

    for (int i=0; i<16; i++) {

        Log.d(LOG_TAG,  "i steht bei: " +i);
        if (bWord[i].equals("")) {
            bWord[i] = newWord;
            Log.d(LOG_TAG, "Word als " + (i+1) + ". Begriff gespeichert.");
            break;
        }
    }
    return bWord;
}