首选项更改后刷新片段

FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, new MyFragment());
transaction.commit();

public class MyViewModel extends ViewModel {
    private MutableLiveData<String> preferenceValue = new MutableLiveData<>();

    public LiveData<String> getPreferenceValue() {
        return preferenceValue;
    }

    public void setPreferenceValue(String value) {
        preferenceValue.setValue(value);
    }
}

public class MyFragment extends Fragment {
    private MyViewModel viewModel;

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        viewModel = ViewModelProviders.of(this).get(MyViewModel.class);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.my_fragment, container, false);
        viewModel.getPreferenceValue().observe(this, new Observer<String>() {
            @Override
            public void onChanged(@Nullable String value) {
                // 更新片段的UI
            }
        });
        return view;
    }
}

SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
sharedPreferences.registerOnSharedPreferenceChangeListener(new SharedPreferences.OnSharedPreferenceChangeListener() {
    @Override
    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
        // 更新片段的UI
    }
});