How we can use bottomSheet in fragment for RecyclerView in android?-CodePudding

I have a simple project, and I want to use bottom sheet for list items in fragment, every things looks good, but after build the project, app crash like that,

a null object reference for row_list.setOnLongClickListener

I do not know where is the problem and how I will fix this problem, maybe my approach is not correct, any idea will be appreciated.

fragment_list:

<FrameLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@ id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/white"
        android:fitsSystemWindows="true"
        tools:context=".view.ListFragment">


    <androidx.recyclerview.widget.RecyclerView
            android:id="@ id/row_list"
            app:layout_behavior="android.support.design.widget.BottomSheetBehavior"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:paddingTop="60dp">
    </androidx.recyclerview.widget.RecyclerView>

   </FrameLayout>

ListFragment:

class ListFragment : Fragment() {

    override fun onCreate(@Nullable savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        row_list.setOnLongClickListener {

            val bottomSheetFragment: BottomSheetDialogFragment = RowItemMenuFragment()
            bottomSheetFragment.show(requireFragmentManager(), bottomSheetFragment.tag)

            true
        }}
    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {

        val view = inflater.inflate(R.layout.fragment_list, container, false)

        return view

    }}}

RowItemMenuFragment:

class RowItemMenuFragment() : BottomSheetDialogFragment()  {


    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {

        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_row_item_menu, container, false)

    }

    override fun onCreate(@Nullable savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setStyle(BottomSheetDialogFragment.STYLE_NORMAL, R.style.BottomSheetDialogTheme)

    }

  }

CodePudding user response：

During onCreate() views are not initialized completely or are in ambiguous state.

Simple answer is to move the view logic to onViewCreated()

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        row_list.setOnLongClickListener {

            val bottomSheetFragment: BottomSheetDialogFragment = RowItemMenuFragment()
            bottomSheetFragment.show(requireFragmentManager(), bottomSheetFragment.tag)

            true
        }
}