我想通過單擊界面按鈕將變量從當前片段返回到上一個片段。我無法從從 Fragment 類擴展的一個 Fragment 返回變量到從 Fragment 類擴展的另一個 Fragment。但我可以通過接口使用相同的傳輸方法將變量從DialogFragment返回到Fragment。在 MainActivity 中我加載 FirstFragment：getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,                new FirstFragment()).commit();在 FirstFragment onClick TextView tvSecondFragment 類中，我創建片段：class FirstFragment extends Fragment implements SecondFragment.SecondFragmentListener {public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {View view = inflater.inflate(R.layout.first_fragment, container, false);        tvSecondFragment.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                Fragment fragment = new SecondFragment();                FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();                fragmentTransaction.add(R.id.fragment_container, fragment);                fragmentTransaction.addToBackStack(null);                fragmentTransaction.commit();            }        });return view;}    @Override    public void sentAge(String input) {        Log.d(TAG, "method sentAge called with variable: " + input);    }}這是 SecondFragment 類，我嘗試在其中返回變量 onClick 按鈕：public class SecondFragment extends Fragment {    private SecondFragmentListener listener;    public interface SecondFragmentListener {        public void sentAge(String input);    }    private EditText editText;    private Button button;    @Nullable    @Override    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {        View view = inflater.inflate(R.layout.second_fragment, container, false);        editText = view.findViewById(R.id.et_age);        button = view.findViewById(R.id.btn_transfer_age);