Replace TypingIndicatorItemDecoration with TypingIndicatorAdapter.

app/src/main/java/org/thoughtcrime/securesms/conversation/mutiselect/MultiselectItemDecoration.kt

@@ -27,6 +27,7 @@ import androidx.core.view.children
 import androidx.core.view.forEach
 import androidx.lifecycle.DefaultLifecycleObserver
 import androidx.lifecycle.LifecycleOwner
+import androidx.recyclerview.widget.ConcatAdapter
 import androidx.recyclerview.widget.RecyclerView
 import com.airbnb.lottie.SimpleColorFilter
 import com.google.android.material.animation.ArgbEvaluatorCompat
@@ -124,7 +125,15 @@ class MultiselectItemDecoration(
   }
 
   private fun getCurrentSelection(parent: RecyclerView): Set<MultiselectPart> {
-    return (parent.adapter as ConversationAdapterBridge).selectedItems
+    return parent.findAdapterBridge().selectedItems
+  }
+
+  private fun RecyclerView.findAdapterBridge(): ConversationAdapterBridge {
+    return when (val parentAdapter = adapter!!) {
+      is ConversationAdapterBridge -> parentAdapter
+      is ConcatAdapter -> (parentAdapter.adapters[1] as ConversationAdapterBridge)
+      else -> error("Unexpected adapter configuration")
+    }
   }
 
   override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
@@ -156,14 +165,14 @@ class MultiselectItemDecoration(
     outRect.setEmpty()
     updateChildOffsets(parent, view)
 
-    consumePulseRequest(parent.adapter as ConversationAdapterBridge)
+    consumePulseRequest(parent.findAdapterBridge())
   }
 
   /**
    * Draws the background shade.
    */
   override fun onDraw(canvas: Canvas, parent: RecyclerView, state: RecyclerView.State) {
-    val adapter = parent.adapter as ConversationAdapterBridge
+    val adapter = parent.findAdapterBridge()
 
     if (adapter.selectedItems.isEmpty()) {
       drawFocusShadeUnderIfNecessary(canvas, parent)
@@ -231,7 +240,7 @@ class MultiselectItemDecoration(
    * Draws the selected check or empty circle.
    */
   override fun onDrawOver(canvas: Canvas, parent: RecyclerView, state: RecyclerView.State) {
-    val adapter = parent.adapter as ConversationAdapterBridge
+    val adapter = parent.findAdapterBridge()
     if (adapter.selectedItems.isEmpty()) {
       drawFocusShadeOverIfNecessary(canvas, parent)
     }
@@ -347,7 +356,7 @@ class MultiselectItemDecoration(
    * called in getItemOffsets to ensure the gutter goes away when multiselect mode ends.
    */
   private fun updateChildOffsets(parent: RecyclerView, child: View) {
-    val adapter = parent.adapter as ConversationAdapterBridge
+    val adapter = parent.findAdapterBridge()
     val isLtr = ViewUtil.isLtr(child)
     val multiselectable: Multiselectable = resolveMultiselectable(parent, child) ?: return
 

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationFragment.kt

@@ -62,6 +62,7 @@ import androidx.lifecycle.DefaultLifecycleObserver
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.LifecycleOwner
 import androidx.lifecycle.Observer
+import androidx.recyclerview.widget.ConcatAdapter
 import androidx.recyclerview.widget.ConversationLayoutManager
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
@@ -468,6 +469,7 @@ class ConversationFragment :
   private lateinit var conversationActivityResultContracts: ConversationActivityResultContracts
   private lateinit var scrollToPositionDelegate: ScrollToPositionDelegate
   private lateinit var adapter: ConversationAdapterV2
+  private lateinit var typingIndicatorAdapter: ConversationTypingIndicatorAdapter
   private lateinit var recyclerViewColorizer: RecyclerViewColorizer
   private lateinit var attachmentManager: AttachmentManager
   private lateinit var multiselectItemDecoration: MultiselectItemDecoration
@@ -475,7 +477,6 @@ class ConversationFragment :
   private lateinit var threadHeaderMarginDecoration: ThreadHeaderMarginDecoration
   private lateinit var conversationItemDecorations: ConversationItemDecorations
   private lateinit var optionsMenuCallback: ConversationOptionsMenuCallback
-  private lateinit var typingIndicatorDecoration: TypingIndicatorDecoration
   private lateinit var backPressedCallback: BackPressedDelegate
 
   private var animationsAllowed = false
@@ -1086,18 +1087,24 @@ class ConversationFragment :
   }
 
   private fun presentTypingIndicator() {
-    typingIndicatorDecoration = TypingIndicatorDecoration(requireContext(), binding.conversationItemRecycler)
-    binding.conversationItemRecycler.addItemDecoration(typingIndicatorDecoration)
+    typingIndicatorAdapter.registerAdapterDataObserver(object : RecyclerView.AdapterDataObserver() {
+      override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
+        if (positionStart == 0 && itemCount == 1 && layoutManager.findFirstCompletelyVisibleItemPosition() == 0) {
+          scrollToPositionDelegate.resetScrollPosition()
+        }
+      }
+    })
 
     ApplicationDependencies.getTypingStatusRepository().getTypists(args.threadId).observe(viewLifecycleOwner) {
       val recipient = viewModel.recipientSnapshot ?: return@observe
 
-      typingIndicatorDecoration.setTypists(
-        GlideApp.with(this),
-        it.typists,
-        recipient.isGroup,
-        recipient.hasWallpaper(),
-        it.isReplacedByIncomingMessage
+      typingIndicatorAdapter.setState(
+        ConversationTypingIndicatorAdapter.State(
+          typists = it.typists,
+          isGroupThread = recipient.isGroup,
+          hasWallpaper = recipient.hasWallpaper(),
+          isReplacedByIncomingMessage = it.isReplacedByIncomingMessage
+        )
       )
     }
   }
@@ -1531,6 +1538,8 @@ class ConversationFragment :
       startExpirationTimeout = viewModel::startExpirationTimeout
     )
 
+    typingIndicatorAdapter = ConversationTypingIndicatorAdapter(GlideApp.with(this))
+
     scrollToPositionDelegate = ScrollToPositionDelegate(
       recyclerView = binding.conversationItemRecycler,
       canJumpToPosition = adapter::canJumpToPosition
@@ -1541,7 +1550,7 @@ class ConversationFragment :
     recyclerViewColorizer = RecyclerViewColorizer(binding.conversationItemRecycler)
     recyclerViewColorizer.setChatColors(args.chatColors)
 
-    binding.conversationItemRecycler.adapter = adapter
+    binding.conversationItemRecycler.adapter = ConcatAdapter(typingIndicatorAdapter, adapter)
     multiselectItemDecoration = MultiselectItemDecoration(
       requireContext()
     ) { viewModel.wallpaperSnapshot }

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationItemDecorations.kt

@@ -55,7 +55,14 @@ class ConversationItemDecorations(hasWallpaper: Boolean = false, private val sch
     }
 
   override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
-    val position = parent.getChildAdapterPosition(view)
+    val viewHolder = parent.getChildViewHolder(view)
+
+    if (viewHolder is ConversationTypingIndicatorAdapter.ViewHolder) {
+      outRect.set(0, 0, 0, 0)
+      return
+    }
+
+    val position = viewHolder.bindingAdapterPosition
 
     val unreadHeight = if (isFirstUnread(position)) {
       getUnreadViewHolder(parent).height
@@ -76,9 +83,15 @@ class ConversationItemDecorations(hasWallpaper: Boolean = false, private val sch
     val count = parent.childCount
     for (layoutPosition in 0 until count) {
       val child = parent.getChildAt(count - 1 - layoutPosition)
-      val position = parent.getChildAdapterPosition(child)
+      val viewHolder = parent.getChildViewHolder(child)
 
-      val unreadOffset = if (isFirstUnread(position)) {
+      if (viewHolder is ConversationTypingIndicatorAdapter.ViewHolder) {
+        continue
+      }
+
+      val bindingAdapterPosition = viewHolder.bindingAdapterPosition
+
+      val unreadOffset = if (isFirstUnread(bindingAdapterPosition)) {
         val unread = getUnreadViewHolder(parent)
         unread.itemView.drawAsTopItemDecoration(c, parent, child)
         unread.height
@@ -86,8 +99,8 @@ class ConversationItemDecorations(hasWallpaper: Boolean = false, private val sch
         0
       }
 
-      if (hasHeader(position)) {
-        val headerView = getHeader(parent, currentItems[position] as ConversationMessageElement).itemView
+      if (hasHeader(bindingAdapterPosition)) {
+        val headerView = getHeader(parent, currentItems[bindingAdapterPosition] as ConversationMessageElement).itemView
         headerView.drawAsTopItemDecoration(c, parent, child, unreadOffset)
       }
     }
@@ -136,18 +149,18 @@ class ConversationItemDecorations(hasWallpaper: Boolean = false, private val sch
     }
   }
 
-  private fun isFirstUnread(position: Int): Boolean {
+  private fun isFirstUnread(bindingAdapterPosition: Int): Boolean {
     val state = unreadState
 
     return state is UnreadState.CompleteUnreadState &&
       state.firstUnreadTimestamp != null &&
-      position in currentItems.indices &&
-      (currentItems[position] as? ConversationMessageElement)?.timestamp() == state.firstUnreadTimestamp
+      bindingAdapterPosition in currentItems.indices &&
+      (currentItems[bindingAdapterPosition] as? ConversationMessageElement)?.timestamp() == state.firstUnreadTimestamp
   }
 
-  private fun hasHeader(position: Int): Boolean {
-    val model = if (position in currentItems.indices) {
-      currentItems[position]
+  private fun hasHeader(bindingAdapterPosition: Int): Boolean {
+    val model = if (bindingAdapterPosition in currentItems.indices) {
+      currentItems[bindingAdapterPosition]
     } else {
       null
     }
@@ -156,7 +169,7 @@ class ConversationItemDecorations(hasWallpaper: Boolean = false, private val sch
       return false
     }
 
-    val previousPosition = position + 1
+    val previousPosition = bindingAdapterPosition + 1
     val previousDay: Long
     if (previousPosition in currentItems.indices) {
       val previousModel = currentItems[previousPosition]

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationTypingIndicatorAdapter.kt

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.thoughtcrime.securesms.conversation.v2
+
+import android.view.LayoutInflater
+import android.view.ViewGroup
+import androidx.recyclerview.widget.RecyclerView
+import org.signal.core.util.toInt
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.components.ConversationTypingView
+import org.thoughtcrime.securesms.mms.GlideRequests
+import org.thoughtcrime.securesms.recipients.Recipient
+
+class ConversationTypingIndicatorAdapter(
+  private val glideRequests: GlideRequests
+) : RecyclerView.Adapter<ConversationTypingIndicatorAdapter.ViewHolder>() {
+
+  private var state: State = State()
+
+  fun setState(state: State) {
+    val isInsert = this.state.typists.isEmpty() && state.typists.isNotEmpty()
+    val isRemoval = state.typists.isEmpty() && this.state.typists.isNotEmpty()
+    val isChange = state.typists.isNotEmpty() && this.state.typists.isNotEmpty()
+
+    this.state = state
+
+    when {
+      isInsert -> notifyItemInserted(0)
+      isRemoval -> notifyItemRemoved(0)
+      isChange -> notifyItemChanged(0)
+      else -> Unit
+    }
+  }
+
+  override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
+    return ViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.conversation_typing_view, parent, false) as ConversationTypingView)
+  }
+
+  override fun getItemCount(): Int = state.typists.isNotEmpty().toInt()
+
+  override fun onBindViewHolder(holder: ViewHolder, position: Int) {
+    holder.bind(glideRequests, state)
+  }
+
+  class ViewHolder(private val conversationTypingView: ConversationTypingView) : RecyclerView.ViewHolder(conversationTypingView) {
+    fun bind(
+      glideRequests: GlideRequests,
+      state: State
+    ) {
+      conversationTypingView.setTypists(
+        glideRequests,
+        state.typists,
+        state.isGroupThread,
+        state.hasWallpaper
+      )
+    }
+  }
+
+  data class State(
+    val typists: List<Recipient> = emptyList(),
+    val hasWallpaper: Boolean = false,
+    val isGroupThread: Boolean = false,
+    val isReplacedByIncomingMessage: Boolean = false // TODO
+  )
+}

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/TypingIndicatorDecoration.kt

@@ -1,149 +0,0 @@
-/*
- * Copyright 2023 Signal Messenger, LLC
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-package org.thoughtcrime.securesms.conversation.v2
-
-import android.animation.ValueAnimator
-import android.content.Context
-import android.graphics.Canvas
-import android.graphics.Rect
-import android.view.LayoutInflater
-import android.view.View
-import android.view.View.MeasureSpec
-import androidx.core.graphics.withTranslation
-import androidx.core.view.children
-import androidx.recyclerview.widget.RecyclerView
-import androidx.recyclerview.widget.RecyclerView.ItemDecoration
-import org.signal.core.util.logging.Log
-import org.thoughtcrime.securesms.R
-import org.thoughtcrime.securesms.components.ConversationTypingView
-import org.thoughtcrime.securesms.mms.GlideRequests
-import org.thoughtcrime.securesms.recipients.Recipient
-
-/**
- * Displays a typing indicator as a part of the very last (first) item in the adapter.
- */
-class TypingIndicatorDecoration(
-  private val context: Context,
-  private val rootView: RecyclerView
-) : ItemDecoration() {
-
-  companion object {
-    private val TAG = Log.tag(TypingIndicatorDecoration::class.java)
-  }
-
-  private val typingView: ConversationTypingView by lazy(LazyThreadSafetyMode.NONE) {
-    LayoutInflater.from(context).inflate(R.layout.conversation_typing_view, rootView, false) as ConversationTypingView
-  }
-
-  private var displayIndicator = false
-  private var animationFraction = 0f
-  private var offsetAnimator: ValueAnimator? = null
-
-  init {
-    rootView.addOnLayoutChangeListener { _, left, top, right, bottom, oldLeft, oldTop, oldRight, oldBottom ->
-      if (left != oldLeft || top != oldTop || right != oldRight || bottom != oldBottom) {
-        remeasureTypingView()
-        rootView.invalidateItemDecorations()
-      }
-    }
-  }
-
-  override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
-    if (!displayIndicator && animationFraction == 0f) {
-      return outRect.set(0, 0, 0, 0)
-    }
-
-    if (parent.getChildAdapterPosition(view) == 0) {
-      remeasureTypingView()
-      outRect.set(0, 0, 0, (typingView.measuredHeight * animationFraction).toInt())
-    } else {
-      outRect.set(0, 0, 0, 0)
-    }
-  }
-
-  override fun onDrawOver(c: Canvas, parent: RecyclerView, state: RecyclerView.State) {
-    if (!displayIndicator && offsetAnimator?.isRunning != true) {
-      return
-    }
-
-    val firstChild = parent.children.firstOrNull() ?: return
-
-    if (parent.getChildAdapterPosition(firstChild) == 0) {
-      c.withTranslation(
-        x = firstChild.left.toFloat(),
-        y = firstChild.bottom.toFloat()
-      ) {
-        typingView.draw(this)
-      }
-
-      if (typingView.isActive) {
-        rootView.post { rootView.invalidateItemDecorations() }
-      }
-    }
-  }
-
-  fun setTypists(
-    glideRequests: GlideRequests,
-    typists: List<Recipient>,
-    isGroupThread: Boolean,
-    hasWallpaper: Boolean,
-    isReplacedByIncomingMessage: Boolean
-  ) {
-    Log.d(TAG, "setTypists: Updating typists: ${typists.size} $isGroupThread $hasWallpaper $isReplacedByIncomingMessage")
-
-    val isEdge = displayIndicator != typists.isNotEmpty()
-    displayIndicator = typists.isNotEmpty()
-
-    typingView.setTypists(
-      glideRequests,
-      typists,
-      isGroupThread,
-      hasWallpaper
-    )
-    remeasureTypingView()
-    rootView.invalidateItemDecorations()
-
-    if (isReplacedByIncomingMessage) {
-      offsetAnimator?.cancel()
-      animationFraction = 0f
-    } else if (isEdge) {
-      animateOffset()
-    }
-  }
-
-  private fun animateOffset() {
-    offsetAnimator?.cancel()
-
-    val (start, end) = if (displayIndicator) {
-      animationFraction to 1f
-    } else {
-      animationFraction to 0f
-    }
-
-    offsetAnimator = ValueAnimator.ofFloat(start, end).apply {
-      addUpdateListener {
-        animationFraction = it.animatedValue as Float
-        rootView.invalidateItemDecorations()
-      }
-      start()
-    }
-  }
-
-  private fun remeasureTypingView() {
-    with(typingView) {
-      measure(
-        MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
-        MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)
-      )
-      layout(
-        0,
-        0,
-        measuredWidth,
-        measuredHeight
-      )
-    }
-  }
-}