ДЗ RecyclerView #2

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

@@ -0,0 +1,10 @@
+package otus.gpb.recyclerview
+
+data class Chat(
+    val id: Int,
+    val title: String,
+    val author: String,
+    val message: String,
+    val time: String,
+    val icon: Int
+)

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

@@ -0,0 +1,94 @@
+package otus.gpb.recyclerview
+
+class DataSource {
+    private val messagesList = listOf(
+        Chat(
+            id = 1,
+            title = "Title1",
+            author = "User1",
+            message = "Message1",
+            time = "12:00",
+            icon = R.drawable.cat
+        ),
+        Chat(
+            id = 2,
+            title = "Title2",
+            author = "User2",
+            message = "Message2",
+            time = "13:05",
+            icon = R.drawable.dog
+        ),
+        Chat(
+            id = 3,
+            title = "Title3",
+            author = "User3",
+            message = "Message3",
+            time = "9:13",
+            icon = R.drawable.fox
+        ),
+        Chat(
+            id = 4,
+            title = "Title4",
+            author = "User4",
+            message = "Message4",
+            time = "4:17",
+            icon = R.drawable.giraffe
+        ),
+        Chat(
+            id = 5,
+            title = "Title5",
+            author = "User5",
+            message = "Message5",
+            time = "10:00",
+            icon = R.drawable.koala
+        ),
+        Chat(
+            id = 6,
+            title = "Title6",
+            author = "User6",
+            message = "Message6",
+            time = "10:35",
+            icon = R.drawable.lion
+        ),
+        Chat(
+            id = 7,
+            title = "Title7",
+            author = "User7",
+            message = "Message7",
+            time = "15:16",
+            icon = R.drawable.owl
+        ),
+        Chat(
+            id = 8,
+            title = "Title8",
+            author = "User8",
+            message = "Message8",
+            time = "16:22",
+            icon = R.drawable.panda
+        ),
+        Chat(
+            id = 9,
+            title = "Title9",
+            author = "User9",
+            message = "Message9",
+            time = "21:18",
+            icon = R.drawable.rabbit
+        ),
+        Chat(
+            id = 10,
+            title = "Title10",
+            author = "User10",
+            message = "Message10",
+            time = "22:45",
+            icon = R.drawable.wolf
+        )
+    )
+
+    fun getMessages(page: Int, pageSize: Int): List<Chat> {
+        val fromIndex = page * pageSize
+        val toIndex = minOf(fromIndex + pageSize, messagesList.size)
+        if (fromIndex >= messagesList.size) return emptyList()
+
+        return messagesList.subList(fromIndex, toIndex)
+    }
+}

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

@@ -0,0 +1,31 @@
+package otus.gpb.recyclerview
+
+import androidx.recyclerview.widget.ItemTouchHelper
+import androidx.recyclerview.widget.RecyclerView
+
+class ItemTouchHelperCallback(private val listener: MessagesAdapterListener) : ItemTouchHelper.Callback() {
+    override fun getMovementFlags(
+        recyclerView: RecyclerView,
+        viewHolder: RecyclerView.ViewHolder
+    ): Int {
+        return makeMovementFlags(
+            0,
+            ItemTouchHelper.LEFT
+        )
+    }
+
+    override fun onMove(
+        recyclerView: RecyclerView,
+        viewHolder: RecyclerView.ViewHolder,
+        target: RecyclerView.ViewHolder
+    ): Boolean {
+        return false
+    }
+
+    override fun onSwiped(
+        viewHolder: RecyclerView.ViewHolder,
+        direction: Int
+    ) {
+        listener.onItemSwipe(viewHolder.adapterPosition)
+    }
+}

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

@@ -2,11 +2,83 @@ package otus.gpb.recyclerview
 
 import androidx.appcompat.app.AppCompatActivity
 import android.os.Bundle
+import androidx.recyclerview.widget.DividerItemDecoration
+import androidx.recyclerview.widget.ItemTouchHelper
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
 
-class MainActivity : AppCompatActivity() {
+class MainActivity : AppCompatActivity(), MessagesAdapterListener {
+
+    private lateinit var recycleView: RecyclerView
+    private lateinit var layoutManager: LinearLayoutManager
+
+    private val messagesAdapter by lazy { MessagesAdapter() }
+    private val messagesListDataSource = DataSource()
+
+    private val pageSize = 7
+    private var currentPage = 0
+    private var isLastPage = false
+
+    private lateinit var scrollListener: ScrollListener
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
+
+        recycleView = findViewById(R.id.recyclerView)
+        layoutManager = LinearLayoutManager(this)
+
+        recycleView.layoutManager = layoutManager
+        recycleView.adapter = messagesAdapter
+        recycleView
+            .addItemDecoration(
+                DividerItemDecoration(
+                    this,
+                    DividerItemDecoration.VERTICAL
+                )
+            )
+
+        ItemTouchHelper(ItemTouchHelperCallback(this))
+            .attachToRecyclerView(recycleView)
+
+        loadFirstPage()
+
+        scrollListener = ScrollListener(layoutManager) {
+            loadNextPage()
+        }
+
+        recycleView.addOnScrollListener(scrollListener)
+
+    }
+
+    private fun loadFirstPage() {
+        val firstPage = messagesListDataSource.getMessages(page = currentPage, pageSize = pageSize)
+        messagesAdapter.submitList(firstPage)
+        currentPage++
+    }
+
+    private fun loadNextPage() {
+        if (isLastPage) return
+
+        val nextPage = messagesListDataSource.getMessages(page = currentPage, pageSize = pageSize)
+
+        if (nextPage.isEmpty()) {
+            isLastPage = true
+            scrollListener.onLoadFinished()
+            return
+        }
+
+        val newList = messagesAdapter.currentList.toMutableList()
+        newList.addAll(nextPage)
+        messagesAdapter.submitList(newList)
+        currentPage++
+
+        scrollListener.onLoadFinished()
+    }
+
+    override fun onItemSwipe(position: Int) {
+        val newList = messagesAdapter.currentList.toMutableList()
+        newList.removeAt(position)
+        messagesAdapter.submitList(newList)
     }
 }

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

@@ -0,0 +1,26 @@
+package otus.gpb.recyclerview
+
+import android.view.View
+import android.widget.ImageView
+import android.widget.TextView
+import androidx.core.content.res.ResourcesCompat
+import androidx.recyclerview.widget.RecyclerView
+
+class MessageViewHolder(val view: View) : RecyclerView.ViewHolder(view) {
+    private val title: TextView = view.findViewById(R.id.title)
+    private val author: TextView = view.findViewById(R.id.author)
+    private val message: TextView = view.findViewById(R.id.message)
+    private val time: TextView = view.findViewById(R.id.time)
+    private val icon: ImageView = view.findViewById(R.id.icon)
+
+    fun bind(chat: Chat) {
+        val drawableImage = ResourcesCompat
+            .getDrawable(view.resources, chat.icon, null)
+        icon.setImageDrawable(drawableImage)
+
+        title.text = chat.title
+        author.text = chat.author
+        message.text = chat.message
+        time.text = chat.time
+    }
+}

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

@@ -0,0 +1,25 @@
+package otus.gpb.recyclerview
+
+import android.view.LayoutInflater
+import android.view.ViewGroup
+import androidx.recyclerview.widget.ListAdapter
+
+class MessagesAdapter() :
+    ListAdapter<Chat, MessageViewHolder>(MessagesDiffCallback()) {
+    override fun onCreateViewHolder(
+        parent: ViewGroup,
+        viewType: Int
+    ): MessageViewHolder {
+        val view = LayoutInflater
+            .from(parent.context)
+            .inflate(R.layout.chat_item, parent, false)
+        return MessageViewHolder(view)
+    }
+
+    override fun onBindViewHolder(
+        holder: MessageViewHolder,
+        position: Int
+    ) {
+        holder.bind(getItem(position))
+    }
+}

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

@@ -0,0 +1,5 @@
+package otus.gpb.recyclerview
+
+interface MessagesAdapterListener {
+    fun onItemSwipe(position: Int)
+}

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

@@ -0,0 +1,14 @@
+package otus.gpb.recyclerview
+
+import androidx.recyclerview.widget.DiffUtil
+
+class MessagesDiffCallback : DiffUtil.ItemCallback<Chat>() {
+
+    override fun areContentsTheSame(oldItem: Chat, newItem: Chat): Boolean {
+        return oldItem == newItem
+    }
+
+    override fun areItemsTheSame(oldItem: Chat, newItem: Chat): Boolean {
+        return oldItem.id == newItem.id
+    }
+}

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

@@ -0,0 +1,30 @@
+package otus.gpb.recyclerview
+
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+
+class ScrollListener(
+    private val layoutManager: LinearLayoutManager,
+    private val loadMore: () -> Unit
+) : RecyclerView.OnScrollListener() {
+
+    private var isLoading = false
+
+    override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
+        if (dy <= 0) return
+
+        val totalItemCount = layoutManager.itemCount
+        val lastVisibleItem = layoutManager.findLastVisibleItemPosition()
+
+        val isAtEnd = lastVisibleItem >= totalItemCount - 1
+
+        if (!isLoading && isAtEnd) {
+            isLoading = true
+            loadMore()
+        }
+    }
+
+    fun onLoadFinished() {
+        isLoading = false
+    }
+}

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

@@ -3,6 +3,7 @@
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     tools:context=".MainActivity">
 
     <androidx.recyclerview.widget.RecyclerView