Refactoring RecyclerView.Adapter to ListAdapter

app/src/main/java/br/com/renatoarg/ui/home/HomeFragment.kt

@@ -1,19 +1,16 @@
 package br.com.renatoarg.ui.home
 
-import android.content.Context
 import android.os.Bundle
 import android.view.View
 import android.widget.ImageView
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.Observer
-import androidx.navigation.fragment.FragmentNavigatorExtras
 import androidx.navigation.fragment.findNavController
 import br.com.renatoarg.R
 import br.com.renatoarg.model.pojo.User
 import br.com.renatoarg.ui.home.adapter.UsersListAdapter
 import br.com.renatoarg.ui.home.adapter.viewholder.UsersListInterface
 import kotlinx.android.synthetic.main.fragment_home.*
-import kotlinx.android.synthetic.main.item_user.*
 import org.koin.androidx.viewmodel.ext.android.sharedViewModel
 import timber.log.Timber
 
@@ -23,12 +20,7 @@ import timber.log.Timber
 class HomeFragment : Fragment(R.layout.fragment_home), UsersListInterface {
 
     private val viewModel: HomeViewModel by sharedViewModel()
-    private lateinit var usersListAdapter : UsersListAdapter
-
-    override fun onAttach(context: Context) {
-        super.onAttach(context)
-        usersListAdapter = UsersListAdapter(context, emptyList(), this)
-    }
+    private val usersListAdapter : UsersListAdapter = UsersListAdapter(this)
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
@@ -48,7 +40,7 @@ class HomeFragment : Fragment(R.layout.fragment_home), UsersListInterface {
     }
 
     private fun setupForUsersLoaded(usersList: List<User>) {
-        usersListAdapter.updateUsers(usersList)
+        usersListAdapter.submitList(usersList)
     }
 
     private fun setupForInit() {

app/src/main/java/br/com/renatoarg/ui/home/adapter/UsersDiffUtilCallback.kt

@@ -0,0 +1,14 @@
+package br.com.renatoarg.ui.home.adapter
+
+import androidx.recyclerview.widget.DiffUtil
+import br.com.renatoarg.model.pojo.User
+
+class UsersDiffUtilCallback : DiffUtil.ItemCallback<User>() {
+    override fun areItemsTheSame(oldItem: User, newItem: User): Boolean {
+        return oldItem == newItem
+    }
+
+    override fun areContentsTheSame(oldItem: User, newItem: User): Boolean {
+        return oldItem == newItem
+    }
+}

app/src/main/java/br/com/renatoarg/ui/home/adapter/UsersListAdapter.kt

@@ -1,57 +1,40 @@
 package br.com.renatoarg.ui.home.adapter
 
-import android.content.Context
-import android.view.LayoutInflater
-import android.view.View
 import android.view.ViewGroup
-import androidx.recyclerview.widget.RecyclerView
-import br.com.renatoarg.R
+import androidx.recyclerview.widget.ListAdapter
 import br.com.renatoarg.model.pojo.User
+import br.com.renatoarg.ui.home.adapter.viewholder.ErrorViewHolder
 import br.com.renatoarg.ui.home.adapter.viewholder.UserOkViewHolder
 import br.com.renatoarg.ui.home.adapter.viewholder.UsersListInterface
+import br.com.renatoarg.ui.home.adapter.viewholder.UsersViewHolder
 
 class UsersListAdapter(
-    private val context: Context,
-    private var users: List<User>,
     private val usersInterface: UsersListInterface
-) : RecyclerView.Adapter<UsersListAdapter.BaseViewHolder<*>>() {
+) : ListAdapter<User, UsersViewHolder>(UsersDiffUtilCallback()) {
 
     companion object {
         private const val TYPE_OK = 0
         private const val TYPE_ERROR = 100
     }
 
-    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BaseViewHolder<*> {
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): UsersViewHolder {
         return when(viewType) {
-            TYPE_OK -> UserOkViewHolder(
-                LayoutInflater.from(context).inflate(R.layout.item_user, parent, false),
-                usersInterface
-            )
+            TYPE_OK -> UserOkViewHolder(parent, usersInterface)
+            TYPE_ERROR -> ErrorViewHolder(parent, usersInterface)
             else -> throw IllegalArgumentException("Invalid view type")
         }
     }
 
     override fun getItemViewType(position: Int): Int {
-        return TYPE_OK
-    }
-
-
-    override fun getItemCount(): Int {
-        return users.size
-    }
-
-    override fun onBindViewHolder(holder: BaseViewHolder<*>, position: Int) {
-        when(holder) {
-            is UserOkViewHolder -> holder.bind(users[position])
+        val firstNameSize = getItem(position).first_name?.length ?: 0
+        return when(firstNameSize){
+            in 0 .. 5 -> TYPE_OK
+            else -> TYPE_ERROR
         }
-    }
 
-    fun updateUsers(usersList: List<User>) {
-        this.users = usersList
-        notifyDataSetChanged()
     }
 
-    abstract class BaseViewHolder<T>(itemView: View) : RecyclerView.ViewHolder(itemView) {
-        abstract fun bind(item: T)
+    override fun onBindViewHolder(holder: UsersViewHolder, position: Int) {
+        holder.bind(getItem(position))
     }
 }

app/src/main/java/br/com/renatoarg/ui/home/adapter/viewholder/ErrorViewHolder.kt

@@ -0,0 +1,36 @@
+package br.com.renatoarg.ui.home.adapter.viewholder
+import android.text.Spannable
+import android.text.SpannableString
+import android.text.style.StrikethroughSpan
+import android.view.LayoutInflater
+import android.view.ViewGroup
+import androidx.core.text.set
+import br.com.renatoarg.R
+import br.com.renatoarg.model.pojo.User
+import com.bumptech.glide.Glide
+import com.bumptech.glide.request.RequestOptions
+import kotlinx.android.synthetic.main.item_user.view.*
+
+class ErrorViewHolder(
+    parent: ViewGroup,
+    usersInterface: UsersListInterface
+) : UsersViewHolder(
+    LayoutInflater.from(parent.context).inflate(R.layout.item_error, parent, false),
+    usersInterface
+) {
+
+    override fun bind(user: User) {
+        super.bind(user)
+        val name = itemView.name.text
+        val spannableString = SpannableString(name)
+        spannableString.setSpan(
+            StrikethroughSpan(),
+            0,
+            user.first_name?.length ?: 0,
+            Spannable.SPAN_EXCLUSIVE_EXCLUSIVE
+        )
+        itemView.name.text = spannableString
+    }
+
+}
+

app/src/main/java/br/com/renatoarg/ui/home/adapter/viewholder/UserOkViewHolder.kt

@@ -1,29 +1,23 @@
 package br.com.renatoarg.ui.home.adapter.viewholder
+import android.view.LayoutInflater
 import android.view.View
+import android.view.ViewGroup
 import android.widget.ImageView
 import android.widget.TextView
 import androidx.constraintlayout.widget.ConstraintLayout
+import androidx.recyclerview.widget.RecyclerView
 import br.com.renatoarg.R
 import br.com.renatoarg.model.pojo.User
 import br.com.renatoarg.ui.home.adapter.UsersListAdapter
 import com.bumptech.glide.Glide
 import com.bumptech.glide.request.RequestOptions
+import kotlinx.android.synthetic.main.item_user.view.*
 
 class UserOkViewHolder(
-    itemView: View,
-    var usersInterface: UsersListInterface
-) :
-        UsersListAdapter.BaseViewHolder<User>(itemView) {
-
-    override fun bind(item: User) {
-        val photo = itemView.findViewById<ImageView>(R.id.photo)
-        Glide.with(itemView.context).load(item.avatar).apply(RequestOptions().circleCrop()).into(photo)
-        itemView.findViewById<TextView>(R.id.name).text = itemView.context.getString(R.string.user_name, item.first_name, item.last_name)
-        itemView.findViewById<TextView>(R.id.email).text = item.email
-        itemView.findViewById<ConstraintLayout>(R.id.wrapper).setOnClickListener {
-            usersInterface.selectUser(item, photo)
-        }
-    }
-
-}
+    parent: ViewGroup,
+    usersInterface: UsersListInterface
+) : UsersViewHolder(
+    LayoutInflater.from(parent.context).inflate(R.layout.item_user, parent, false),
+    usersInterface
+)
 

app/src/main/java/br/com/renatoarg/ui/home/adapter/viewholder/UsersViewHolder.kt

@@ -0,0 +1,30 @@
+package br.com.renatoarg.ui.home.adapter.viewholder
+
+import android.view.View
+import androidx.recyclerview.widget.RecyclerView
+import br.com.renatoarg.R
+import br.com.renatoarg.model.pojo.User
+import com.bumptech.glide.Glide
+import com.bumptech.glide.request.RequestOptions
+import kotlinx.android.synthetic.main.item_user.view.*
+
+abstract class UsersViewHolder(
+    itemView : View,
+    private val usersInterface: UsersListInterface
+) : RecyclerView.ViewHolder(itemView) {
+    open fun bind(user : User){
+        with(itemView){
+
+            Glide.with(itemView.context)
+                .load(user.avatar)
+                .apply(RequestOptions().circleCrop())
+                .into(photo)
+
+            name.text = itemView.context.getString(R.string.user_name, user.first_name, user.last_name)
+            email.text = user.email
+            wrapper.setOnClickListener {
+                usersInterface.selectUser(user, photo)
+            }
+        }
+    }
+}

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

@@ -0,0 +1,40 @@
+<?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:id="@+id/wrapper"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:background="@color/colorAccent"
+    android:padding="16dp">
+
+    <ImageView
+        android:id="@+id/photo"
+        android:layout_width="@dimen/photo_size"
+        android:layout_height="@dimen/photo_size"
+        android:transitionName="photo"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <TextView
+        android:id="@+id/name"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="8dp"
+        android:textAppearance="@style/TextAppearance.AppCompat.Title"
+        app:layout_constraintStart_toEndOf="@+id/photo"
+        app:layout_constraintTop_toTopOf="parent"
+        tools:text="Fulano de tal" />
+
+    <TextView
+        android:id="@+id/email"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="8dp"
+        android:layout_marginLeft="8dp"
+        app:layout_constraintStart_toEndOf="@+id/photo"
+        app:layout_constraintTop_toBottomOf="@+id/name"
+        tools:text="[email protected]" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>