空参数捆绑在片段中

Question

将参数从活动传递到片段时，参数将丢失。

活动：

public class DatePickerFragmentActivity extends AppCompatActivity {

    private static final String EXTRA_CRIME_DATE = "CRIME_DATE";
    private Date mCrimeDate;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fragment);
        mCrimeDate = (Date) getIntent().getSerializableExtra(EXTRA_CRIME_DATE);
        FragmentManager fm = getSupportFragmentManager();
        Fragment fragment = fm.findFragmentById(R.id.fragment_container);
        if (fragment == null) {
            fragment = createFragment();
            fm.beginTransaction().add(R.id.fragment_container, fragment).commit();
        }
    }

    private Fragment createFragment(){
        return DatePickerFragment.newInstance(mCrimeDate);
    }
}

这时，片段仍然有束中的数据，由调试器检查。

    fm.beginTransaction().add(R.id.fragment_container, fragment).commit();

片段：

public class DatePickerFragment extends DialogFragment {

    private static final String ARG_DATE = "date";

    public static DatePickerFragment newInstance(Date date) {
        Bundle args = new Bundle();
        args.putSerializable(ARG_DATE, date);

        DatePickerFragment fragment = new DatePickerFragment();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mDate = (Date) getArguments().getSerializable(ARG_DATE);
    }

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

但是在这个地方，捆绑包已经是空的：

mDate = (Date) getArguments().getSerializable(ARG_DATE);

我的应用程序的布局如下：

ListView活动/片段-> ViewPager活动/片段-> DatePicker活动/片段