Ahmad-Hamwi

/**
 *     Example:
 *
 *     <!--parent container (that's expanded to fullscreen)-->
 *     <androidx.constraintlayout.widget.ConstraintLayout
 *         android:layout_width="match_parent"
 *         android:layout_height="match_parent"
 *         ...
 *         app:applySystemBarsInsetOnPadding="@{true}">
 *         ...

Ahmad-Hamwi

/**
 *     example:
 *
 *     <!--parent container (that's expanded to fullscreen)-->
 *     <androidx.constraintlayout.widget.ConstraintLayout
 *         android:layout_width="match_parent"
 *         android:layout_height="match_parent"
 *         ...
 *         app:setDecorFitSystemWindow="@{true}">
 *         ...

Ahmad-Hamwi

class Item(val content: String) {

}

Ahmad-Hamwi

class Category(val name: String, vararg item: Item) {

    val listOfItems: List<Item> = item.toList()

}

Ahmad-Hamwi

class ItemsAdapter(
    private val context: Context,
    private var items: List<Item>
) :
    RecyclerView.Adapter<ItemsAdapter.ItemViewHolder>() {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ItemViewHolder {
        return ItemViewHolder(
            LayoutInflater.from(context).inflate(R.layout.item_item, parent, false)
        )

Ahmad-Hamwi

class CategoriesAdapter(
    private val context: Context,
    private val listOfCategories: List<Category>
) : RecyclerView.Adapter<CategoriesAdapter.CategoryViewHolder>() {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CategoryViewHolder {
        return CategoryViewHolder(
            LayoutInflater.from(context).inflate(R.layout.item_category, parent, false)
        )
    }

Ahmad-Hamwi

private val categories = mutableListOf(
    Category(
        "Category 1",
        Item("Item 1"),
        Item("Item 2"),
        Item("Item 3"),
        Item("Item 4"),
        Item("Item 5"),
        Item("Item 6")
    ),

Ahmad-Hamwi

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    initViews()
    initTabLayout()
    initRecycler()
}

private fun initViews() {

Ahmad-Hamwi

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    initViews()
    initTabLayout()
    initRecycler()
    initMediator() // NEW
}

Ahmad-Hamwi

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.MainActivity">

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/tabLayout"