RecyclerView Selection (Long Key)

dependencies {
    implementation 'androidx.recyclerview:recyclerview-selection:1.0.0'
    // implementation 'androidx.recyclerview:recyclerview-selection:1.1.0-rc01'
}

class TestSelectionFragment : Fragment() {    private lateinit var adapter: LocalAdapter    override fun onCreateView(        inflater: LayoutInflater, container: ViewGroup?,        savedInstanceState: Bundle?    ): View? {        return inflater.inflate(R.layout.testselection, container, false)    }    override fun onActivityCreated(savedInstanceState: Bundle?) {        super.onActivityCreated(savedInstanceState)        initList()    }    private fun initList() {        val layoutManager = GridLayoutManager(context, 3)        list.layoutManager = layoutManager        if (!::adapter.isInitialized) {            adapter = LocalAdapter()            adapter.setHasStableIds(true)            list.adapter = adapter            val tracker = SelectionTracker.Builder<Long>(                "number-selection",                list,                StableIdKeyProvider(list),                LocalItemDetailsLookup(list),                StorageStrategy.createLongStorage()            ).withSelectionPredicate(                SelectionPredicates.createSelectAnything()            ).build()            adapter.tracker = tracker            tracker.addObserver(object : SelectionTracker.SelectionObserver<Long>() {                override fun onSelectionChanged() {                    super.onSelectionChanged()                    Timber.d("selection=${tracker.selection}")                }            })        }        val items = mutableListOf<ViewItem>()        for (number in 1..10) {            items.add(ViewItem.NumberItem(number.toString()))        }        adapter.submitList(items)    }    private class LocalItemDetailsLookup(private val recyclerView: RecyclerView) :        ItemDetailsLookup<Long>() {        override fun getItemDetails(event: MotionEvent): ItemDetails<Long>? {            val view = recyclerView.findChildViewUnder(event.x, event.y)            if (view != null) {                return (recyclerView.getChildViewHolder(view) as LocalAdapter.ViewHolder)                    .getItemDetails()            }            return null        }    }    sealed class ViewItem(open val id: String, val resource: Int) {        data class NumberItem(override val id: String) : ViewItem(id, R.layout.testselection_item)    }    class LocalAdapter() : ListAdapter<ViewItem, LocalAdapter.ViewHolder>(DiffCallback()) {        lateinit var tracker: SelectionTracker<Long>        override fun getItemId(position: Int): Long = position.toLong()        override fun getItemViewType(position: Int): Int {            return getItem(position).resource        }        override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {            val view = LayoutInflater.from(parent.context)                .inflate(viewType, parent, false)            return ViewHolder(view)        }        override fun onBindViewHolder(holder: ViewHolder, position: Int) {            Timber.d("position=$position, selected=${tracker.isSelected(position.toLong())}, selection=${tracker.selection}")            holder.bind(getItem(position), tracker.isSelected(position.toLong()))        }        private class DiffCallback: DiffUtil.ItemCallback<ViewItem>() {            override fun areItemsTheSame(oldItem: ViewItem, newItem: ViewItem): Boolean {                if (oldItem.resource != newItem.resource) return false                // check if id is the same                return oldItem.id == newItem.id            }            @SuppressLint("DiffUtilEquals")            override fun areContentsTheSame(oldItem: ViewItem, newItem: ViewItem): Boolean {                // check if content is the same                // equals using data class                return oldItem == newItem            }        }        inner class ViewHolder(override val containerView: View) : RecyclerView.ViewHolder(containerView),            LayoutContainer {            // why update ui here? easier to access view without need to holder.titleTextView            fun bind(item: ViewItem, isSelected: Boolean) {                when(item) {                    is ViewItem.NumberItem -> {                        numberTextView.text = item.id                        val res = if (isSelected) R.drawable.ic_baseline_check_circle_24 else R.drawable.ic_baseline_radio_button_unchecked_24                        selectionImageView.setImageResource(res)                    }                }            }            fun getItemDetails(): ItemDetailsLookup.ItemDetails<Long> =                object : ItemDetailsLookup.ItemDetails<Long>() {                    override fun getPosition(): Int = adapterPosition                    override fun getSelectionKey(): Long? = itemId                }        }    }}

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    tools:context="com.luasoftware.garden.view.TestSelectionFragment">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/list"
        app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</FrameLayout>

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:tools="http://schemas.android.com/tools"
    tools:layout_height="500dp">

    <TextView
        android:id="@+id/numberTextView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:gravity="center"
        app:layout_constraintDimensionRatio="H,1:1"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:text="Test">

    </TextView>


    <ImageView
        android:id="@+id/selectionImageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="8dp"
        android:src="@drawable/ic_baseline_radio_button_unchecked_24"
        android:tint="@android:color/black"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>