我正在从我的片段中实现一个日期选择器。我想在我的片段中显示选定的日期。

日期选择器对话框片段：

class DatePickerDialogFragment :  DialogFragment() , DatePickerDialog.OnDateSetListener {

    @NotNull
    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        //return super.onCreateDialog(savedInstanceState)
        // Use the current date as the default date in the picker.
        val c: Calendar = Calendar.getInstance()
        val year: Int = c.get(Calendar.YEAR)
        val month: Int = c.get(Calendar.MONTH)
        val day: Int = c.get(Calendar.DAY_OF_MONTH)
        // Create a new instance of DatePickerDialog and return it.
        return DatePickerDialog(requireActivity(), this, year, month, day)
    }

    override fun onDateSet(view: DatePicker?, year: Int, month: Int, dayOfMonth: Int) {
        val selectedDate = arrayOf<String>(year.toString(),month.toString(),dayOfMonth.toString())
        val action = DatePickerDialogFragmentDirections.actionDatePickerDialogFragmentToDatePickerDemo(month.toString(),year.toString(),dayOfMonth.toString())
        //Navigation.findNavController().navigate(action)
        findNavController().navigate(action)
    }
}

DatePickerDemo类：

class DatePickerDemo : Fragment() ,View.OnClickListener {
    private var mSelectedMonth: String? = null
    private var mSelectedDay: String? = null
    private var mSelectedYear: String? = null
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_date_picker, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        btnShowDate.setOnClickListener(this)
        arguments?.let {
            mSelectedMonth = DatePickerDemoArgs.fromBundle(it).month.toString()
            mSelectedDay = DatePickerDemoArgs.fromBundle(it).day.toString()
            mSelectedYear = DatePickerDemoArgs.fromBundle(it).year.toString()
        }
        if(mSelectedMonth != null && mSelectedDay != null && mSelectedYear != null){
            processDatePickerResult(mSelectedYear!!.toInt(),mSelectedMonth!!.toInt(),mSelectedDay!!.toInt())
        }
    }

    override fun onClick(v: View?) {
        findNavController().navigate(R.id.datePickerDialogFragment)
    }
}

片段和对话框片段的导航图如下所示：

<fragment
        android:id="@+id/datePickerDemo"
        android:name="com.kgandroid.droidcafeuimaster.DatePickerDemo"
        android:label="DatePickerDemo" >
        <action
            android:id="@+id/action_datePickerDemo_to_datePickerDialogFragment"
            app:destination="@id/datePickerDialogFragment" />
        <argument
            android:name="year"
            app:argType="string"
            app:nullable="true"
            android:defaultValue="@null" />
        <argument
            android:name="month"
            app:argType="string"
            app:nullable="true"
            android:defaultValue="@null" />
        <argument
            android:name="day"
            app:argType="string"
            app:nullable="true"
            android:defaultValue="@null" />
    </fragment>
  <dialog
        android:id="@+id/datePickerDialogFragment"
        android:name="com.kgandroid.droidcafeuimaster.DatePickerDialogFragment"
        android:label="fragment_date_picker_dialog"
        tools:layout="@layout/fragment_date_picker_dialog" >
        <action
            android:id="@+id/action_datePickerDialogFragment_to_datePickerDemo"
            app:destination="@id/datePickerDemo" />
    </dialog>

问题在于：
很明显，当DatePikerDemo片段启动时，我不需要其中的参数。当我从DatePickerDialogFragment返回并将其显示为吐司时，我需要这些参数。因此，我向参数添加了null值，如您所见：**app：nullable=“true”android：defaultValue="@null”**在导航图中。但问题是，编译器显示错误：

公共开放式功能操作DatePickerDialogFragmentToDatePickerDemo的参数太多

如果没有默认值，程序将进行编译，但会崩溃并显示错误：

java.lang.IllegalArgumentException: Required argument "year" is missing and does not have an android:defaultValue

这是很明显的。那么这个问题的解决方案是什么呢？
注意到在通过导航库从片段到日志以及从日志到片段的通信时会出现此类问题。