Merge pull request #13 from intive-FDV/troubleshooting/paging_adapter_scrolling_bug

[Fix] scroll bug + column width

Author: andres-seoane-intive

app/src/main/java/com/intive/tmdbandroid/common/TVShowAsyncPagingDataDiffCallback.kt

@@ -0,0 +1,14 @@
+package com.intive.tmdbandroid.common
+
+import androidx.recyclerview.widget.DiffUtil
+import com.intive.tmdbandroid.model.TVShow
+
+class TVShowAsyncPagingDataDiffCallback : DiffUtil.ItemCallback<TVShow>() {
+    override fun areItemsTheSame(oldItem: TVShow, newItem: TVShow): Boolean {
+        return oldItem.id == newItem.id
+    }
+
+    override fun areContentsTheSame(oldItem: TVShow, newItem: TVShow): Boolean {
+        return oldItem == newItem
+    }
+}

app/src/main/java/com/intive/tmdbandroid/home/ui/HomeFragment.kt

@@ -28,7 +28,11 @@ import kotlin.math.floor
 class HomeFragment : Fragment() {
     private val viewModel: HomeViewModel by viewModels()
 
-    private lateinit var tvShowPageAdapter: TVShowPageAdapter
+    private val clickListener = { tvShow: TVShow ->
+        val action = HomeFragmentDirections.actionHomeFragmentDestToTVShowDetail(tvShow.id)
+        findNavController().navigate(action)
+    }
+    private val tvShowPageAdapter = TVShowPageAdapter(clickListener)
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -122,17 +126,12 @@ class HomeFragment : Fragment() {
     private fun initViews(binding: FragmentHomeBinding) {
         val rvTopTVShows = binding.rvPopularTVShows
 
-        val clickListener = { tvShow: TVShow ->
-            val action = HomeFragmentDirections.actionHomeFragmentDestToTVShowDetail(tvShow.id)
-            findNavController().navigate(action)
-        }
-        tvShowPageAdapter = TVShowPageAdapter(clickListener)
-
         rvTopTVShows.apply {
             val displayMetrics = context.resources.displayMetrics
             val dpWidth = displayMetrics.widthPixels / displayMetrics.density
+            Timber.i("MAS - dpWidth: $dpWidth")
 
-            val scaling = 200
+            val scaling = resources.getInteger(R.integer.screening_width)
             val columnCount = floor(dpWidth / scaling).toInt()
             Timber.i("MAS - columnCount: $columnCount")
 
@@ -146,6 +145,8 @@ class HomeFragment : Fragment() {
                 }
             }
 
+            tvShowPageAdapter.widthSize = ((floor(dpWidth / columnCount) - resources.getInteger(R.integer.short_padding)) * displayMetrics.density).toInt()
+
             layoutManager = manager
             adapter = tvShowPageAdapter
         }

app/src/main/java/com/intive/tmdbandroid/home/ui/adapters/TVShowPageAdapter.kt

@@ -3,55 +3,83 @@ package com.intive.tmdbandroid.home.ui.adapters
 import android.content.res.Resources
 import android.view.LayoutInflater
 import android.view.ViewGroup
-import androidx.paging.PagingDataAdapter
-import androidx.recyclerview.widget.DiffUtil
-import androidx.recyclerview.widget.LinearLayoutManager
-import androidx.recyclerview.widget.RecyclerView
+import androidx.paging.AsyncPagingDataDiffer
+import androidx.paging.PagingData
+import androidx.recyclerview.widget.*
 import com.intive.tmdbandroid.R
+import com.intive.tmdbandroid.common.TVShowAsyncPagingDataDiffCallback
 import com.intive.tmdbandroid.databinding.ItemHorizontalListBinding
 import com.intive.tmdbandroid.databinding.ItemScreeningBinding
 import com.intive.tmdbandroid.databinding.ItemTitleBinding
 import com.intive.tmdbandroid.model.TVShow
 
-class TVShowPageAdapter(private val clickListener: ((TVShow) -> Unit)) : PagingDataAdapter<TVShow, RecyclerView.ViewHolder>(COMPARATOR) {
+class TVShowPageAdapter(private val clickListener: ((TVShow) -> Unit)) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
     companion object {
-        private val COMPARATOR = object : DiffUtil.ItemCallback<TVShow>() {
-            override fun areItemsTheSame(oldItem: TVShow, newItem: TVShow): Boolean = (oldItem == newItem)
-            override fun areContentsTheSame(oldItem: TVShow, newItem: TVShow): Boolean = (oldItem == newItem)
-        }
-
         private const val HEADER = 0
         private const val WATCHLIST = 1
         private const val POPULAR = 2
     }
 
+    var widthSize: Int = 0
+    val adapterCallback = AdapterListUpdateCallback(this)
+
+    private val differ = AsyncPagingDataDiffer(
+        TVShowAsyncPagingDataDiffCallback(),
+        object : ListUpdateCallback {
+            override fun onInserted(position: Int, count: Int) {
+                adapterCallback.onInserted(position + 1, count)
+            }
+
+            override fun onRemoved(position: Int, count: Int) {
+                adapterCallback.onRemoved(position + 1, count)
+            }
+
+            override fun onMoved(fromPosition: Int, toPosition: Int) {
+                adapterCallback.onMoved(fromPosition + 1, toPosition + 1)
+            }
+
+            override fun onChanged(position: Int, count: Int, payload: Any?) {
+                adapterCallback.onChanged(position + 1, count, payload)
+            }
+        }
+    )
+
+    suspend fun submitData(tvShowPagingData: PagingData<TVShow>) {
+        differ.submitData(tvShowPagingData)
+    }
+
     private val watchlistAdapter = WatchlistAdapter(clickListener)
 
+    override fun getItemCount(): Int {
+        return differ.itemCount + 3
+    }
+
     fun refreshWatchlistAdapter(list: List<TVShow>) {
         watchlistAdapter.submitList(list)
     }
 
     override fun getItemViewType(position: Int): Int {
         return when (position) {
-            0,2 -> HEADER
+            0, 2 -> HEADER
             1 -> WATCHLIST
             else -> POPULAR
         }
     }
 
     override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
+
         when (holder) {
             is HeaderHolder -> holder.bind(position)
             is WatchlistHolder -> holder.bind()
-            is TVShowHolder -> getItem(position - 3)?.let { holder.bind(it) }
+            is TVShowHolder -> differ.getItem(position - 3)?.let { holder.bind(it) }
         }
     }
 
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
         return when (viewType) {
             HEADER -> HeaderHolder(ItemTitleBinding.inflate(LayoutInflater.from(parent.context), parent, false))
             WATCHLIST -> WatchlistHolder(ItemHorizontalListBinding.inflate(LayoutInflater.from(parent.context), parent, false))
-            POPULAR -> TVShowHolder(ItemScreeningBinding.inflate(LayoutInflater.from(parent.context), parent, false), clickListener )
+            POPULAR -> TVShowHolder(ItemScreeningBinding.inflate(LayoutInflater.from(parent.context), parent, false), clickListener)
             else -> throw Exception("Illegal ViewType")
         }
     }
@@ -78,6 +106,7 @@ class TVShowPageAdapter(private val clickListener: ((TVShow) -> Unit)) : PagingD
         fun bind() {
             rvWatchlist.apply {
                 layoutManager = LinearLayoutManager(itemView.context, LinearLayoutManager.HORIZONTAL, false)
+                watchlistAdapter.widthSize = widthSize
                 adapter = watchlistAdapter
             }
         }

app/src/main/java/com/intive/tmdbandroid/home/ui/adapters/WatchlistAdapter.kt

@@ -6,8 +6,11 @@ import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ListAdapter
 import com.intive.tmdbandroid.databinding.ItemScreeningBinding
 import com.intive.tmdbandroid.model.TVShow
+import timber.log.Timber
 
 class WatchlistAdapter(private val clickListener: ((TVShow) -> Unit)) : ListAdapter<TVShow, TVShowHolder>(COMPARATOR) {
+    var widthSize: Int = 0
+
     companion object {
         private val COMPARATOR = object : DiffUtil.ItemCallback<TVShow>() {
             override fun areItemsTheSame(oldItem: TVShow, newItem: TVShow): Boolean = (oldItem == newItem)
@@ -19,8 +22,14 @@ class WatchlistAdapter(private val clickListener: ((TVShow) -> Unit)) : ListAdap
         holder.bind(getItem(position))
     }
 
-    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): TVShowHolder = TVShowHolder(
-        ItemScreeningBinding.inflate(LayoutInflater.from(parent.context), parent, false),
-        clickListener
-    )
-}
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): TVShowHolder {
+        val binding = ItemScreeningBinding.inflate(LayoutInflater.from(parent.context), parent, false)
+        Timber.i("MAS - width: $widthSize")
+        binding.screeningContainer.layoutParams.width = widthSize
+
+        return TVShowHolder(
+            binding,
+            clickListener
+        )
+    }
+}

app/src/main/res/drawable/poster_placeholder.jpg

@@ -1,34 +1,32 @@
 <?xml version="1.0" encoding="utf-8"?>
 
 <androidx.cardview.widget.CardView
+    android:id="@+id/screening_container"
     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="wrap_content"
+    android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    android:layout_marginTop="8dp"
-    android:layout_marginEnd="8dp"
-    android:layout_marginStart="8dp"
-    android:layout_marginBottom="16dp"
+    android:layout_margin="8dp"
+    android:paddingBottom="8dp"
     app:cardCornerRadius="5dp"
     android:elevation="5dp">
 
     <androidx.constraintlayout.widget.ConstraintLayout
-        android:layout_width="wrap_content"
+        android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_gravity="center">
 
         <androidx.appcompat.widget.AppCompatImageView
             android:id="@+id/screening_poster"
-            android:layout_width="wrap_content"
+            android:layout_width="match_parent"
             android:layout_height="0dp"
-            android:minWidth="192dp"
             app:layout_constraintDimensionRatio="1:1.5"
             app:layout_constraintHorizontal_bias="0.0"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintTop_toTopOf="parent"
-            tools:src="@drawable/ic_launcher_foreground" />
+            tools:src="@drawable/poster_placeholder" />
 
         <androidx.appcompat.widget.AppCompatTextView
             android:id="@+id/screening_title"

app/src/main/res/layout/item_screening.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <integer name="screening_width">100</integer>
+    <integer name="short_padding">8</integer>
+</resources>

app/src/main/res/values-w200dp/integer.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <integer name="screening_width">150</integer>
+    <integer name="short_padding">8</integer>
+</resources>

app/src/main/res/values-w300dp/integer.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <integer name="screening_width">200</integer>
+    <integer name="short_padding">8</integer>
+</resources>

app/src/main/res/values-w400dp/integer.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <integer name="screening_width">250</integer>
+    <integer name="short_padding">8</integer>
+</resources>