Otus-Android · Werechess · Nov 28, 2025
diff --git a/app/src/main/java/ru/otus/cryptosample/coins/feature/CoinListFragment.kt b/app/src/main/java/ru/otus/cryptosample/coins/feature/CoinListFragment.kt
@@ -14,6 +14,7 @@ import androidx.recyclerview.widget.GridLayoutManager
 import kotlinx.coroutines.launch
 import ru.otus.cryptosample.CoinsSampleApp
 import ru.otus.cryptosample.coins.feature.adapter.CoinsAdapter
+import ru.otus.cryptosample.coins.feature.adapter.CustomItemAnimator
 import ru.otus.cryptosample.coins.feature.di.DaggerCoinListComponent
 import ru.otus.cryptosample.databinding.FragmentCoinListBinding
 import javax.inject.Inject
@@ -67,6 +68,7 @@ class CoinListFragment : Fragment() {
                 return when (coinsAdapter.getItemViewType(position)) {
                     0 -> 2 // Category header spans full width
                     1 -> 1 // Coin item spans half width
+                    2 -> 2 // Carousel spans full width
                     else -> 1
                 }
             }
@@ -75,6 +77,8 @@ class CoinListFragment : Fragment() {
         binding.recyclerView.apply {
             layoutManager = gridLayoutManager
             adapter = coinsAdapter
+            itemAnimator = CustomItemAnimator()
+            setRecycledViewPool(CoinsAdapter.sharedPool)
         }
     }
 

diff --git a/app/src/main/java/ru/otus/cryptosample/coins/feature/adapter/CarouselAdapter.kt b/app/src/main/java/ru/otus/cryptosample/coins/feature/adapter/CarouselAdapter.kt
@@ -0,0 +1,43 @@
+package ru.otus.cryptosample.coins.feature.adapter
+
+import android.view.LayoutInflater
+import android.view.ViewGroup
+import androidx.recyclerview.widget.DiffUtil
+import androidx.recyclerview.widget.ListAdapter
+import androidx.recyclerview.widget.RecyclerView
+import ru.otus.cryptosample.coins.feature.CoinState
+import ru.otus.cryptosample.databinding.ItemCoinBinding
+
+class CarouselAdapter : ListAdapter<CoinState, CoinViewHolder>(CarouselDiffUtil) {
+
+    override fun getItemCount(): Int = currentList.size
+
+    override fun getItemViewType(position: Int): Int = CoinsAdapter.VIEW_TYPE_COIN
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CoinViewHolder {
+        val binding = ItemCoinBinding.inflate(LayoutInflater.from(parent.context), parent, false)
+        val params = binding.root.layoutParams
+            ?: RecyclerView.LayoutParams(
+                RecyclerView.LayoutParams.WRAP_CONTENT,
+                RecyclerView.LayoutParams.WRAP_CONTENT
+            )
+        val screenWidth = parent.resources.displayMetrics.widthPixels
+        params.width = (screenWidth / 2) - 16
+
+        binding.root.layoutParams = params
+        return CoinViewHolder(binding)
+    }
+
+    override fun onBindViewHolder(holder: CoinViewHolder, position: Int) {
+        holder.bind(getItem(position))
+    }
+
+    override fun onBindViewHolder(holder: CoinViewHolder, position: Int, payloads: List<Any>) {
+        holder.bind(getItem(position), payloads)
+    }
+}
+
+object CarouselDiffUtil : DiffUtil.ItemCallback<CoinState>() {
+    override fun areItemsTheSame(old: CoinState, new: CoinState) = old.id == new.id
+    override fun areContentsTheSame(old: CoinState, new: CoinState) = old == new
+}
diff --git a/app/src/main/java/ru/otus/cryptosample/coins/feature/adapter/CarouselViewHolder.kt b/app/src/main/java/ru/otus/cryptosample/coins/feature/adapter/CarouselViewHolder.kt
@@ -0,0 +1,29 @@
+package ru.otus.cryptosample.coins.feature.adapter
+
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import ru.otus.cryptosample.coins.feature.CoinState
+import ru.otus.cryptosample.databinding.ItemCarouselBinding
+
+class CarouselViewHolder(
+    binding: ItemCarouselBinding,
+    sharedPool: RecyclerView.RecycledViewPool
+) : RecyclerView.ViewHolder(binding.root) {
+
+    private val carouselAdapter = CarouselAdapter()
+
+    init {
+        binding.carouselRecyclerView.apply {
+            layoutManager = LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false)
+            adapter = carouselAdapter
+            setRecycledViewPool(sharedPool)
+            setHasFixedSize(true)
+            isNestedScrollingEnabled = false
+            itemAnimator = CustomItemAnimator()
+        }
+    }
+
+    fun bind(coins: List<CoinState>) {
+        carouselAdapter.submitList(coins)
+    }
+}
diff --git a/app/src/main/java/ru/otus/cryptosample/coins/feature/adapter/CoinViewHolder.kt b/app/src/main/java/ru/otus/cryptosample/coins/feature/adapter/CoinViewHolder.kt
@@ -1,5 +1,6 @@
 package ru.otus.cryptosample.coins.feature.adapter
 
+import android.os.Bundle
 import androidx.core.content.ContextCompat
 import androidx.core.view.isVisible
 import androidx.recyclerview.widget.RecyclerView
@@ -33,4 +34,19 @@ class CoinViewHolder(
             fireBadge.isVisible = coin.highlight
         }
     }
+
+    fun bind(coin: CoinState, payloads: List<Any>) {
+        if (payloads.isNotEmpty()) {
+            val bundle = payloads[0] as Bundle
+            if (bundle.containsKey("highlight")) {
+                updateHighlight(bundle.getBoolean("highlight"))
+            }
+        } else {
+            bind(coin)
+        }
+    }
+
+    private fun updateHighlight(highlight: Boolean) {
+        binding.fireBadge.isVisible = highlight
+    }
 }
diff --git a/app/src/main/java/ru/otus/cryptosample/coins/feature/adapter/CoinsAdapter.kt b/app/src/main/java/ru/otus/cryptosample/coins/feature/adapter/CoinsAdapter.kt
@@ -1,44 +1,58 @@
 package ru.otus.cryptosample.coins.feature.adapter
 
+import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.ViewGroup
+import androidx.recyclerview.widget.DiffUtil
+import androidx.recyclerview.widget.ListAdapter
 import androidx.recyclerview.widget.RecyclerView
 import ru.otus.cryptosample.coins.feature.CoinCategoryState
+import ru.otus.cryptosample.coins.feature.adapter.CoinsAdapterItem.CarouselItems
+import ru.otus.cryptosample.coins.feature.adapter.CoinsAdapterItem.CategoryHeader
+import ru.otus.cryptosample.coins.feature.adapter.CoinsAdapterItem.CoinItem
+import ru.otus.cryptosample.databinding.ItemCarouselBinding
 import ru.otus.cryptosample.databinding.ItemCategoryHeaderBinding
 import ru.otus.cryptosample.databinding.ItemCoinBinding
 
-class CoinsAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
-    
+class CoinsAdapter : ListAdapter<CoinsAdapterItem, RecyclerView.ViewHolder>(CoinDiffUtil) {
+
     companion object {
-        private const val VIEW_TYPE_CATEGORY = 0
-        private const val VIEW_TYPE_COIN = 1
+        const val VIEW_TYPE_CATEGORY = 0
+        const val VIEW_TYPE_COIN = 1
+        const val VIEW_TYPE_CAROUSEL = 2
+
+        val sharedPool = RecyclerView.RecycledViewPool()
     }
-
-    private var items = listOf<CoinsAdapterItem>()
-
+
     fun setData(categories: List<CoinCategoryState>) {
         val adapterItems = mutableListOf<CoinsAdapterItem>()
-        
+
         categories.forEach { category ->
-            adapterItems.add(CoinsAdapterItem.CategoryHeader(category.name))
-            category.coins.forEach { coin ->
-                adapterItems.add(CoinsAdapterItem.CoinItem(coin))
+            adapterItems.add(CategoryHeader(category.name))
+            when (category.coins.size) {
+                in 0..10 -> {
+                    category.coins.forEach { coin ->
+                        adapterItems.add(CoinItem(coin))
+                    }
+                }
+
+                else -> adapterItems.add(CarouselItems(category.coins))
             }
         }
-
-        items = adapterItems
-        notifyDataSetChanged()
+
+        submitList(adapterItems)
     }
-    
-    override fun getItemCount(): Int = items.size
-    
+
+    override fun getItemCount(): Int = currentList.size
+
     override fun getItemViewType(position: Int): Int {
-        return when (items[position]) {
-            is CoinsAdapterItem.CategoryHeader -> VIEW_TYPE_CATEGORY
-            is CoinsAdapterItem.CoinItem -> VIEW_TYPE_COIN
+        return when (getItem(position)) {
+            is CategoryHeader -> VIEW_TYPE_CATEGORY
+            is CoinItem -> VIEW_TYPE_COIN
+            is CarouselItems -> VIEW_TYPE_CAROUSEL
         }
     }
-    
+
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
         return when (viewType) {
             VIEW_TYPE_CATEGORY -> CategoryHeaderViewHolder(
@@ -48,25 +62,100 @@ class CoinsAdapter : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
                     false
                 )
             )
-            VIEW_TYPE_COIN -> CoinViewHolder(
-                ItemCoinBinding.inflate(
-                    LayoutInflater.from(parent.context),
-                    parent,
-                    false
+
+            VIEW_TYPE_COIN -> {
+                val binding =
+                    ItemCoinBinding.inflate(LayoutInflater.from(parent.context), parent, false)
+                val params = binding.root.layoutParams
+                    ?: RecyclerView.LayoutParams(
+                        RecyclerView.LayoutParams.WRAP_CONTENT,
+                        RecyclerView.LayoutParams.WRAP_CONTENT
+                    )
+                val screenWidth = parent.resources.displayMetrics.widthPixels
+                params.width = (screenWidth / 2) - 16
+
+                binding.root.layoutParams = params
+                CoinViewHolder(binding)
+            }
+
+            VIEW_TYPE_CAROUSEL -> {
+                CarouselViewHolder(
+                    ItemCarouselBinding.inflate(
+                        LayoutInflater.from(parent.context),
+                        parent,
+                        false
+                    ),
+                    sharedPool
                 )
-            )
+            }
+
             else -> throw IllegalArgumentException("Unknown view type: $viewType")
         }
     }
-    
+
     override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
-        when (val item = items[position]) {
-            is CoinsAdapterItem.CategoryHeader -> {
+        when (val item = getItem(position)) {
+            is CategoryHeader -> {
                 (holder as CategoryHeaderViewHolder).bind(item.categoryName)
             }
-            is CoinsAdapterItem.CoinItem -> {
+
+            is CoinItem -> {
                 (holder as CoinViewHolder).bind(item.coin)
             }
+
+            is CarouselItems -> {
+                (holder as CarouselViewHolder).bind(item.coins)
+            }
         }
     }
+
+    override fun onBindViewHolder(
+        holder: RecyclerView.ViewHolder,
+        position: Int,
+        payloads: List<Any>
+    ) {
+        when (val item = getItem(position)) {
+            is CategoryHeader -> {
+                (holder as CategoryHeaderViewHolder).bind(item.categoryName)
+            }
+
+            is CoinItem -> {
+                if (payloads.isNotEmpty()) {
+                    (holder as CoinViewHolder).bind(item.coin, payloads)
+                } else {
+                    (holder as CoinViewHolder).bind(item.coin)
+                }
+            }
+
+            is CarouselItems -> {
+                (holder as CarouselViewHolder).bind(item.coins)
+            }
+        }
+    }
+}
+
+object CoinDiffUtil : DiffUtil.ItemCallback<CoinsAdapterItem>() {
+
+    override fun areItemsTheSame(
+        oldItem: CoinsAdapterItem,
+        newItem: CoinsAdapterItem
+    ): Boolean = when (oldItem) {
+        is CategoryHeader if newItem is CategoryHeader -> oldItem.categoryName == newItem.categoryName
+        is CoinItem if newItem is CoinItem -> oldItem.coin.id == newItem.coin.id
+        is CarouselItems if newItem is CarouselItems -> oldItem.coins.size == newItem.coins.size
+        else -> false
+    }
+
+    override fun areContentsTheSame(oldItem: CoinsAdapterItem, newItem: CoinsAdapterItem): Boolean =
+        oldItem == newItem
+
+    override fun getChangePayload(oldItem: CoinsAdapterItem, newItem: CoinsAdapterItem): Any? {
+        if (oldItem is CoinItem && newItem is CoinItem) {
+            val diffBundle = Bundle()
+            if (oldItem.coin.highlight != newItem.coin.highlight) {
+                diffBundle.putBoolean("highlight", newItem.coin.highlight)
+            }
+            return if (diffBundle.size() > 0) diffBundle else null
+        } else return super.getChangePayload(oldItem, newItem)
+    }
 }
diff --git a/app/src/main/java/ru/otus/cryptosample/coins/feature/adapter/CoinsAdapterItem.kt b/app/src/main/java/ru/otus/cryptosample/coins/feature/adapter/CoinsAdapterItem.kt
@@ -5,4 +5,5 @@ import ru.otus.cryptosample.coins.feature.CoinState
 sealed class CoinsAdapterItem {
     data class CategoryHeader(val categoryName: String) : CoinsAdapterItem()
     data class CoinItem(val coin: CoinState) : CoinsAdapterItem()
+    data class CarouselItems(val coins: List<CoinState>) : CoinsAdapterItem()
 }