尝试通过Adapter从Fragment添加项目时，Spinner＆ViewPager2显示为空白

Question

以前，我使用TabLayout和ViewPager1来显示DialogFragment中的内容，但是现在我想将Spinner和ViewPager2一起使用。当我使用与Spinner相关的代码时，它会导致应用程序崩溃，并且Spinner显示为空白，这使我感到困惑。有谁知道为什么我的微调框不显示任何项目，而ViewPager2不显示任何Fragments，以及如何确认呢？

问题似乎出在这部分代码，logcat指向该部分：

val arrayAdapter = ArrayAdapter(view!!.context, R.layout.my_spinnerItem, myTabTitles)
arrayAdapter.setDropDownViewResource(R.layout.my_spinnerItem)
mSpinner.adapter = arrayAdapter

XML（我以前使用过）

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    <com.google.android.material.tabs.TabLayout
            android:id="@+id/myTabLayout"
            android:layout_width="match_parent"
            android:layout_height="?android:attr/actionBarSize"
            app:tabMode="scrollable"
            app:tabGravity="fill" />

        <androidx.viewpager.widget.ViewPager
                android:id="@+id/myViewPager"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"/>

</LinearLayout>

XML（我想改用什么）

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    <Spinner
            android:id="@+id/mySpinner"
            style="@style/Widget.AppCompat.Spinner.Underlined"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:spinnerMode="dialog" />

    <androidx.viewpager2.widget.ViewPager2
            android:id="@+id/myViewPagerV2"
            android:layout_height="0dp"
            android:layout_width="match_parent"
            android:layout_weight="1" />

</LinearLayout>

Kotlin（我以前使用过的东西）

class TabbedDialog(
    private val myTitle: String,
    private val myTabTitles: ArrayList<String>,
    private val myTabDescriptions: ArrayList<String>
) : DialogFragment() {
    private lateinit var customView: View

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

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {

        val b = AlertDialog.Builder(activity)
            .setTitle(myTitle)
            .setPositiveButton(getString(android.R.string.ok)) { dialog, _ -> dialog.dismiss() }

        customView = activity!!.layoutInflater.inflate(R.layout.fragment_dialog, null)

        val tabLayout = customView.myTabLayout
        val viewPager = customView.myViewPager

        val adapter = MyViewPagerAdapter(childFragmentManager)

        myTabTitles.forEachIndexed { index, item ->
            adapter.addFragment(
                item,
                FragmentDialogContent.createInstance(myTabDescriptions[index])
            )
        }

        viewPager.adapter = adapter
        tabLayout.setupWithViewPager(viewPager)


        b.setView(customView)
        return b.create()
    }
}

MyViewPagerAdapter类

class MyViewPagerAdapter(manager: FragmentManager) :
    FragmentPagerAdapter(manager, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) {
    private val titleList: MutableList<String> = ArrayList()
    private val fragmentList: MutableList<Fragment> = ArrayList()

    override fun getItem(position: Int): Fragment {
        return fragmentList[position]
    }

    override fun getCount(): Int {
        return fragmentList.size
    }

    fun addFragment(title: String, fragment: Fragment) {
        titleList.add(title)
        fragmentList.add(fragment)
    }

    override fun getPageTitle(position: Int): CharSequence? {
        return titleList[position]
    }
}

科特琳（我尝试了什么）

class TabbedDialog1(
    private val myTitle: String,
    private val myTabTitles: ArrayList<String>,
    private val myTabDescriptions: ArrayList<String>
) : DialogFragment() {
    private lateinit var customView: View

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

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {

        val b = AlertDialog.Builder(activity)
            .setIcon(R.drawable.ic_night)
            .setTitle(myTitle)
            .setPositiveButton(getString(android.R.string.ok)) { dialog, _ -> dialog.dismiss() }

        customView = activity!!.layoutInflater.inflate(R.layout.fragment_dialog_1, null)

        val mSpinner = customView.mSpinnerV2
        val mViewPager = customView.mViewPagerV2

        val mAdapter = MyViewPagerAdapter(childFragmentManager)

        val arrayAdapter = ArrayAdapter(view!!.context, R.layout.my_spinnerItem, myTabTitles)
        arrayAdapter.setDropDownViewResource(R.layout.my_spinnerItem)
        mSpinner.adapter = arrayAdapter

        myTabTitles.forEachIndexed { index, item ->
            mAdapter.addFragment(
                item,
                FragmentDialogContent.createInstance(myTabDescriptions[index])
            )
        }


        mViewPager.orientation = ViewPager2.ORIENTATION_HORIZONTAL

        b.setView(customView)
        return b.create()
    }
}

片段类

class MyFragment : androidx.fragment.app.Fragment() {
    private lateinit var mRecyclerView: RecyclerView

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

    override fun onActivityCreated(savedInstanceState: Bundle?) {
        val v = view

        mRecyclerView = v!!.mRecyclerViewSansToolbar
        mRecyclerView.layoutManager = LinearLayoutManager(activity)

        val listFacilities = ArrayList<Item>()

        val myDialogTitle = "Hello World"

        val myTabTitles = ArrayList<String>()
        myTabTitles.add("Tab 1")
        myTabTitles.add("Tab 2")
        myTabTitles.add("Tab 3")
        myTabTitles.add("Tab 4")
        myDialogTabTitles.add("Tab 5")

        val myTabDescriptions = ArrayList<String>()
        myTabDescriptions.add("Description 1")
        myTabDescriptions.add("Description 2")
        myTabDescriptions.add("Description 3")
        myTabDescriptions.add("Description 4")
        myDialogTabDescriptions.add("Description 5")

        super.onActivityCreated(savedInstanceState)
    }
}