Suppress LayoutTransition during scroll events.

app/src/androidTest/java/org/thoughtcrime/securesms/conversation/v2/items/V2ConversationItemShapeTest.kt

@@ -217,6 +217,7 @@ class V2ConversationItemShapeTest {
     override val isMessageRequestAccepted: Boolean = true
     override val searchQuery: String? = null
     override val glideRequests: GlideRequests = mockk()
+    override val isParentInScroll: Boolean = false
 
     override fun onStartExpirationTimeout(messageRecord: MessageRecord) = Unit
 

app/src/main/java/org/thoughtcrime/securesms/BindableConversationItem.java

@@ -57,6 +57,10 @@ public interface BindableConversationItem extends Unbindable, GiphyMp4Playable,
 
   void setEventListener(@Nullable EventListener listener);
 
+  default void setParentScrolling(boolean isParentScrolling) {
+    // Intentionally Blank.
+  }
+
   default void updateTimestamps() {
     // Intentionally Blank.
   }

app/src/main/java/org/thoughtcrime/securesms/conversation/ConversationAdapterBridge.kt

@@ -16,6 +16,7 @@ interface ConversationAdapterBridge {
     const val PAYLOAD_TIMESTAMP = 0
     const val PAYLOAD_NAME_COLORS = 1
     const val PAYLOAD_SELECTED = 2
+    const val PAYLOAD_PARENT_SCROLLING = 3
   }
 
   fun hasNoConversationMessages(): Boolean

app/src/main/java/org/thoughtcrime/securesms/conversation/ConversationItem.java

@@ -418,6 +418,11 @@ public final class ConversationItem extends RelativeLayout implements BindableCo
     this.conversationRecipient.observeForever(this);
   }
 
+  @Override
+  public void setParentScrolling(boolean isParentScrolling) {
+    bodyBubble.setParentScrolling(isParentScrolling);
+  }
+
   @Override
   public void updateSelectedState() {
     setHasBeenQuoted(conversationMessage);

app/src/main/java/org/thoughtcrime/securesms/conversation/ConversationItemBodyBubble.java

@@ -12,6 +12,7 @@ import androidx.annotation.Nullable;
 import com.annimon.stream.Collectors;
 import com.annimon.stream.Stream;
 
+import org.signal.core.util.logging.Log;
 import org.thoughtcrime.securesms.components.Outliner;
 import org.thoughtcrime.securesms.util.Projection;
 import org.thoughtcrime.securesms.util.Util;
@@ -30,19 +31,33 @@ public class ConversationItemBodyBubble extends LinearLayout {
   private Projection             quoteViewProjection;
   private Projection             videoPlayerProjection;
 
+  private final BodyBubbleLayoutTransition bodyBubbleLayoutTransition = new BodyBubbleLayoutTransition();
+
   public ConversationItemBodyBubble(Context context) {
     super(context);
-    setLayoutTransition(new BodyBubbleLayoutTransition());
+    init();
   }
 
   public ConversationItemBodyBubble(Context context, @Nullable AttributeSet attrs) {
     super(context, attrs);
-    setLayoutTransition(new BodyBubbleLayoutTransition());
+    init();
   }
 
   public ConversationItemBodyBubble(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
     super(context, attrs, defStyleAttr);
-    setLayoutTransition(new BodyBubbleLayoutTransition());
+    init();
+  }
+
+  private void init() {
+    setLayoutTransition(bodyBubbleLayoutTransition);
+  }
+
+  public void setParentScrolling(boolean isParentScrolling) {
+    if (isParentScrolling) {
+      setLayoutTransition(null);
+    } else {
+      setLayoutTransition(bodyBubbleLayoutTransition);
+    }
   }
 
   public void setOutliners(@NonNull List<Outliner> outliners) {

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/ConversationAdapterV2.kt

@@ -90,6 +90,10 @@ class ConversationAdapterV2(
 
   override var isMessageRequestAccepted: Boolean = false
 
+  override var isParentInScroll: Boolean = false
+
+  private val onScrollStateChangedListener = OnScrollStateChangedListener()
+
   init {
     registerFactory(ThreadHeader::class.java, ::ThreadHeaderViewHolder, R.layout.conversation_item_thread_header)
 
@@ -162,6 +166,8 @@ class ConversationAdapterV2(
         recyclerView.recycledViewPool.setMaxRecycledViews(type, count)
       }
     }
+
+    recyclerView.addOnScrollListener(onScrollStateChangedListener)
   }
 
   override fun onViewRecycled(holder: MappingViewHolder<*>) {
@@ -176,6 +182,8 @@ class ConversationAdapterV2(
       .children
       .filterIsInstance<Unbindable>()
       .forEach { it.unbind() }
+
+    recyclerView.removeOnScrollListener(onScrollStateChangedListener)
   }
 
   override val displayMode: ConversationItemDisplayMode
@@ -498,6 +506,11 @@ class ConversationAdapterV2(
     fun bindPayloadsIfAvailable(): Boolean {
       var payloadApplied = false
 
+      bindable.setParentScrolling(isParentInScroll)
+      if (payload.contains(ConversationAdapterBridge.PAYLOAD_PARENT_SCROLLING)) {
+        payloadApplied = true
+      }
+
       if (payload.contains(ConversationAdapterBridge.PAYLOAD_TIMESTAMP)) {
         bindable.updateTimestamps()
         payloadApplied = true
@@ -627,4 +640,14 @@ class ConversationAdapterV2(
       }
     }
   }
+
+  private inner class OnScrollStateChangedListener : RecyclerView.OnScrollListener() {
+    override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
+      val oldState = isParentInScroll
+      isParentInScroll = newState != RecyclerView.SCROLL_STATE_IDLE
+      if (isParentInScroll != oldState) {
+        notifyItemRangeChanged(0, itemCount, ConversationAdapterBridge.PAYLOAD_PARENT_SCROLLING)
+      }
+    }
+  }
 }

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/items/V2ConversationContext.kt

@@ -23,6 +23,7 @@ interface V2ConversationContext {
   val selectedItems: Set<MultiselectPart>
   val isMessageRequestAccepted: Boolean
   val searchQuery: String?
+  val isParentInScroll: Boolean
 
   fun onStartExpirationTimeout(messageRecord: MessageRecord)
 

app/src/main/java/org/thoughtcrime/securesms/conversation/v2/items/V2ConversationItemTextOnlyViewHolder.kt

@@ -100,6 +100,7 @@ open class V2ConversationItemTextOnlyViewHolder<Model : MappingModel<Model>>(
 
   private val bodyBubbleDrawable = ChatColorsDrawable()
   private val footerDrawable = ChatColorsDrawable()
+  private val bodyBubbleLayoutTransition = BodyBubbleLayoutTransition()
 
   protected lateinit var shape: V2ConversationItemShape.MessageShape
 
@@ -155,7 +156,7 @@ open class V2ConversationItemTextOnlyViewHolder<Model : MappingModel<Model>>(
     }
 
     binding.conversationItemBodyWrapper.background = bodyBubbleDrawable
-    binding.conversationItemBodyWrapper.layoutTransition = BodyBubbleLayoutTransition()
+    binding.conversationItemBodyWrapper.layoutTransition = bodyBubbleLayoutTransition
 
     binding.conversationItemFooterBackground.background = footerDrawable
   }
@@ -166,6 +167,22 @@ open class V2ConversationItemTextOnlyViewHolder<Model : MappingModel<Model>>(
   }
 
   override fun bind(model: Model) {
+    var hasProcessedSupportedPayload = false
+
+    binding.conversationItemBodyWrapper.layoutTransition = if (conversationContext.isParentInScroll) {
+      null
+    } else {
+      bodyBubbleLayoutTransition
+    }
+
+    if (ConversationAdapterBridge.PAYLOAD_PARENT_SCROLLING in payload) {
+      if (payload.size == 1) {
+        return
+      } else {
+        hasProcessedSupportedPayload = true
+      }
+    }
+
     check(model is ConversationMessageElement)
     conversationMessage = model.conversationMessage
 
@@ -176,7 +193,6 @@ open class V2ConversationItemTextOnlyViewHolder<Model : MappingModel<Model>>(
       adapterPosition = bindingAdapterPosition
     )
 
-    var hasProcessedSupportedPayload = false
     if (ConversationAdapterBridge.PAYLOAD_TIMESTAMP in payload) {
       presentDate()
       hasProcessedSupportedPayload = true