Решение к домашней работе #RecyclerView

app/build.gradle

@@ -17,6 +17,10 @@ android {
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
 
+    buildFeatures {
+        viewBinding = true
+    }
+
     buildTypes {
         release {
             minifyEnabled false
@@ -41,4 +45,8 @@ dependencies {
     testImplementation 'junit:junit:4.13.2'
     androidTestImplementation 'androidx.test.ext:junit:1.1.3'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
+
+    // Glide для оптимизированной загрузки изображений
+    implementation 'com.github.bumptech.glide:glide:4.16.0'
+    annotationProcessor 'com.github.bumptech.glide:compiler:4.16.0'
 }

app/src/main/AndroidManifest.xml

@@ -2,6 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools">
 
+    <uses-permission android:name="android.permission.INTERNET" />
+
     <application
         android:allowBackup="true"
         android:dataExtractionRules="@xml/data_extraction_rules"

app/src/main/java/otus/gpb/recyclerview/AppGlideModule.kt

@@ -0,0 +1,11 @@
+package otus.gpb.recyclerview
+
+import com.bumptech.glide.annotation.GlideModule
+import com.bumptech.glide.module.AppGlideModule
+
+/**
+ * Модуль Glide для оптимизации загрузки изображений
+ * Устраняет предупреждение о GeneratedAppGlideModule
+ */
+@GlideModule
+class AppGlideModule : AppGlideModule()

app/src/main/java/otus/gpb/recyclerview/ChatAdapter.kt

@@ -0,0 +1,261 @@
+package otus.gpb.recyclerview
+
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.ImageView
+import android.widget.TextView
+import androidx.recyclerview.widget.DiffUtil
+import androidx.recyclerview.widget.ListAdapter
+import androidx.recyclerview.widget.RecyclerView
+import com.bumptech.glide.Glide
+import otus.gpb.recyclerview.databinding.ViewHolderGroupBinding
+import otus.gpb.recyclerview.databinding.ViewHolderPersonBinding
+
+class ChatAdapter(private val onItemClick: (Int) -> Unit) :
+    ListAdapter<ChatItem, RecyclerView.ViewHolder>(ChatDiffCallback()) {
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
+        return when (ViewTypes.fromId(viewType)) {
+            ViewTypes.GROUP -> {
+                val binding = ViewHolderGroupBinding.inflate(LayoutInflater.from(parent.context), parent, false)
+                GroupChatViewHolder(binding)
+            }
+            ViewTypes.PERSON -> {
+                val binding = ViewHolderPersonBinding.inflate(LayoutInflater.from(parent.context), parent, false)
+                PersonChatViewHolder(binding)
+            }
+            null -> throw IllegalArgumentException("Unknown view type: $viewType")
+        }
+    }
+
+    override fun getItemViewType(position: Int): Int {
+        return when (getItem(position)) {
+            is GroupChat -> ViewTypes.GROUP.id
+            is PersonChat -> ViewTypes.PERSON.id
+            else -> throw IllegalArgumentException("Unknown item type: ${getItem(position)}")
+        }
+    }
+
+    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
+        // привязка данных с проверкой типа и границ
+        if (position < 0 || position >= itemCount) return
+
+        try {
+            when (holder) {
+                is GroupChatViewHolder -> {
+                    val item = getItem(position)
+                    if (item is GroupChat) {
+                        holder.bind(item)
+                    }
+                }
+                is PersonChatViewHolder -> {
+                    val item = getItem(position)
+                    if (item is PersonChat) {
+                        holder.bind(item)
+                    }
+                }
+            }
+            resetViewAppearance(holder.itemView)
+        } catch (e: Exception) {
+            // логируем ошибку и сбрасываем внешний вид View
+            e.printStackTrace()
+            resetViewAppearance(holder.itemView)
+        }
+    }
+
+    fun removeItem(position: Int) {
+        if (position >= 0 && position < currentList.size) {
+            val newList = currentList.toMutableList().apply { removeAt(position) }
+            submitList(newList)
+        }
+    }
+
+    private fun resetViewAppearance(view: View) {
+        view.alpha = 1f
+        view.scaleX = 1f
+        view.scaleY = 1f
+    }
+
+    inner class GroupChatViewHolder(private val binding: ViewHolderGroupBinding) :
+        RecyclerView.ViewHolder(binding.root) {
+
+        fun bind(item: GroupChat) {
+            // кэшируем часто используемые View
+            with(binding) {
+                // Аватар с оптимизацией
+                loadAvatar(item.avatarUrl, imgGroupAvatar, R.drawable.group_badge)
+                // бейджи и иконки
+                imgVoipBadgeContainer.visibility = item.voip.toVisibility()
+                imgVerifiedIcon.visibility = item.verified.toVisibility()
+                imgMuteIcon.visibility = item.muted.toVisibility()
+                // тексты
+                txtGroupName.text = item.groupName
+                txtLastAuthor.text = item.lastAuthor
+                txtLastMessage.text = item.lastMessage
+                txtTimeValue.text = item.time
+                // preview сообщения
+                setupMessagePreview(item.messagePreviewUrl, imgMessagePreviewContainer, imgMessagePreview)
+                // статусы прочтения
+                setupReadStatus(item.checked, item.read, imgCheckedIcon, imgReadIcon)
+                // счетчик
+                setupCounter(item.counter, imgCounterContainer, txtCounterContainer)
+                // дополнительные иконки
+                imgPinnedIcon.visibility = item.pinned.toVisibility()
+                imgMentionIconContainer.visibility = item.mentioned.toVisibility()
+
+                root.setOnClickListener { onItemClick(item.id) }
+            }
+        }
+    }
+
+    inner class PersonChatViewHolder(private val binding: ViewHolderPersonBinding) :
+        RecyclerView.ViewHolder(binding.root) {
+
+        fun bind(item: PersonChat) {
+            with(binding) {
+                // аватар
+                loadAvatar(item.avatarUrl, imgPersonAvatar, R.drawable.person_badge)
+                // бейджи статусов
+                setupPersonBadges(item.checkbox, item.online, item.locked)
+                // тексты
+                txtPersonName.text = item.personName
+                txtLastMessage.text = item.lastMessage
+                txtTimeValue.text = item.time
+                // иконки верификации и scam
+                setupVerificationAndScam(item.verified, item.scam)
+                imgMuteIcon.visibility = item.muted.toVisibility()
+                // preview сообщения с оптимизацией
+                setupMessagePreview(item.messagePreviewUrl, imgMessagePreviewContainer, imgMessagePreview)
+                // статусы прочтения
+                setupReadStatus(item.checked, item.read, imgCheckedIcon, imgReadIcon)
+                // счётчик
+                setupCounter(item.counter, imgCounterContainer, txtCounterContainer)
+                // дополнительные иконки
+                imgPinnedIcon.visibility = item.pinned.toVisibility()
+                imgMentionIconContainer.visibility = item.mentioned.toVisibility()
+
+                root.setOnClickListener { onItemClick(item.id) }
+            }
+        }
+
+        private fun setupPersonBadges(checkbox: Boolean, online: Boolean, locked: Boolean) {
+            with(binding) {
+                imgCheckboxBadgeContainer.visibility = (checkbox && !online).toVisibility()
+                imgOnlineBadgeContainer.visibility = online.toVisibility()
+                imgLockedIcon.visibility = locked.toVisibility()
+            }
+        }
+
+        private fun setupVerificationAndScam(verified: Boolean, scam: Boolean) {
+            with(binding) {
+                imgScamPatch.visibility = scam.toVisibility()
+                imgVerifiedIcon.visibility = (verified && !scam).toVisibility()
+            }
+        }
+    }
+
+    // extension functions для загрузки изображений (эксперимент с оптимизацией)
+    private fun loadAvatar(avatarUrl: String, imageView: ImageView, placeholder: Int) {
+        if (avatarUrl.isNotEmpty()) {
+            Glide.with(imageView.context)
+                .load(avatarUrl)
+                .centerCrop()
+                .placeholder(placeholder)
+                .error(placeholder) // Добавляем error placeholder
+                .diskCacheStrategy(com.bumptech.glide.load.engine.DiskCacheStrategy.ALL) // Кэшируем все
+                .skipMemoryCache(false) // Используем память для быстрого доступа
+                .thumbnail(0.1f) // Показываем уменьшенную версию сначала
+                .into(imageView)
+        } else {
+            imageView.setImageResource(placeholder)
+        }
+    }
+
+    private fun setupMessagePreview(previewUrl: String, container: View, imageView: ImageView) {
+        if (previewUrl.isNotEmpty()) {
+            container.visibility = View.VISIBLE
+            Glide.with(imageView.context)
+                .load(previewUrl)
+                .centerCrop()
+                .diskCacheStrategy(com.bumptech.glide.load.engine.DiskCacheStrategy.ALL)
+                .skipMemoryCache(false)
+                .thumbnail(0.1f)
+                .into(imageView)
+        } else {
+            container.visibility = View.GONE
+        }
+    }
+
+    private fun setupReadStatus(checked: Boolean, read: Boolean, checkedIcon: ImageView, readIcon: ImageView) {
+        checkedIcon.visibility = (checked && !read).toVisibility()
+        readIcon.visibility = read.toVisibility()
+    }
+
+    private fun setupCounter(counter: Int, container: View, counterText: TextView) {
+        if (counter == 0) {
+            container.visibility = View.GONE
+        } else {
+            container.visibility = View.VISIBLE
+            counterText.text = counter.toString()
+        }
+    }
+
+    private fun Boolean.toVisibility() = if (this) View.VISIBLE else View.GONE
+
+    enum class ViewTypes(val id: Int) {
+        GROUP(R.layout.view_holder_group),
+        PERSON(R.layout.view_holder_person);
+
+        companion object {
+            fun fromId(id: Int) = ViewTypes.entries.find { it.id == id }
+        }
+    }
+}
+
+class ChatDiffCallback : DiffUtil.ItemCallback<ChatItem>() {
+    override fun areItemsTheSame(oldItem: ChatItem, newItem: ChatItem): Boolean {
+        return oldItem.id == newItem.id
+    }
+
+    override fun areContentsTheSame(oldItem: ChatItem, newItem: ChatItem): Boolean {
+        // сравнение содержимого для избежания лишних перерисовок
+        return when {
+            oldItem is GroupChat && newItem is GroupChat -> {
+                oldItem.groupName == newItem.groupName &&
+                oldItem.lastAuthor == newItem.lastAuthor &&
+                oldItem.lastMessage == newItem.lastMessage &&
+                oldItem.avatarUrl == newItem.avatarUrl &&
+                oldItem.messagePreviewUrl == newItem.messagePreviewUrl &&
+                oldItem.voip == newItem.voip &&
+                oldItem.verified == newItem.verified &&
+                oldItem.muted == newItem.muted &&
+                oldItem.time == newItem.time &&
+                oldItem.checked == newItem.checked &&
+                oldItem.read == newItem.read &&
+                oldItem.mentioned == newItem.mentioned &&
+                oldItem.pinned == newItem.pinned &&
+                oldItem.counter == newItem.counter
+            }
+            oldItem is PersonChat && newItem is PersonChat -> {
+                oldItem.personName == newItem.personName &&
+                oldItem.lastMessage == newItem.lastMessage &&
+                oldItem.avatarUrl == newItem.avatarUrl &&
+                oldItem.messagePreviewUrl == newItem.messagePreviewUrl &&
+                oldItem.checkbox == newItem.checkbox &&
+                oldItem.online == newItem.online &&
+                oldItem.locked == newItem.locked &&
+                oldItem.scam == newItem.scam &&
+                oldItem.verified == newItem.verified &&
+                oldItem.muted == newItem.muted &&
+                oldItem.time == newItem.time &&
+                oldItem.checked == newItem.checked &&
+                oldItem.read == newItem.read &&
+                oldItem.mentioned == newItem.mentioned &&
+                oldItem.pinned == newItem.pinned &&
+                oldItem.counter == newItem.counter
+            }
+            else -> false
+        }
+    }
+}

app/src/main/java/otus/gpb/recyclerview/ChatItem.kt

@@ -0,0 +1,5 @@
+package otus.gpb.recyclerview
+
+interface ChatItem {
+    val id: Int
+}

app/src/main/java/otus/gpb/recyclerview/CustomDecorator.kt

@@ -0,0 +1,51 @@
+package otus.gpb.recyclerview
+
+import android.content.Context
+import android.content.res.Resources
+import android.graphics.Canvas
+import android.graphics.Paint
+import android.graphics.Rect
+import androidx.recyclerview.widget.DividerItemDecoration
+import androidx.recyclerview.widget.RecyclerView
+
+class CustomDecorator(private val context: Context) : DividerItemDecoration(context, VERTICAL) {
+
+    private val bounds = Rect()
+    private val paint = Paint()
+    private var offset = 0
+    private var color = 0xFF000000.toInt()
+
+    override fun onDraw(c: Canvas, parent: RecyclerView, state: RecyclerView.State) {
+        paint.color = color
+
+        val childCount = parent.childCount
+        for (index: Int in 0 until childCount) {
+            val child = parent.getChildAt(index)
+            parent.getDecoratedBoundsWithMargins(child, bounds)
+            bounds.left += offset
+
+            val positionCurrent = parent.getChildAdapterPosition(child)
+            if (positionCurrent != RecyclerView.NO_POSITION) {
+                val lastElementPosition = parent.adapter?.itemCount?.minus(1)
+                if (positionCurrent != lastElementPosition) {
+                    c.drawLine(
+                        (bounds.left).toFloat(),
+                        bounds.bottom.toFloat(),
+                        bounds.right.toFloat(),
+                        bounds.bottom.toFloat(),
+                        paint
+                    )
+                }
+            }
+        }
+    }
+
+    fun setColor(id: Int) {
+        color = context.getColor(id)
+    }
+
+    fun setOffset(id: Int) { //73
+        offset =
+            (context.resources.getInteger(id) * Resources.getSystem().displayMetrics.density).toInt()
+    }
+}