Add CFV2 Scroll-to-position wiring.

app/src/main/java/org/thoughtcrime/securesms/components/ScrollToPositionDelegate.kt

@@ -52,9 +52,36 @@ class ScrollToPositionDelegate private constructor(
         recyclerView.doAfterNextLayout {
           handleScrollPositionRequest(position, recyclerView)
         }
+
+        if (!(recyclerView.isLayoutRequested || recyclerView.isInLayout)) {
+          recyclerView.requestLayout()
+        }
       })
   }
 
+  /**
+   * Entry point for requesting a specific scroll position.
+   */
+  fun requestScrollPosition(position: Int, smooth: Boolean = true) {
+    scrollPositionRequested.onNext(ScrollToPositionRequest(position, smooth))
+  }
+
+  /**
+   * Reset the scroll position to 0
+   */
+  fun resetScrollPosition() {
+    requestScrollPosition(0, true)
+  }
+
+  /**
+   * This should be called every time a list is submitted to the RecyclerView's adapter.
+   */
+  fun notifyListCommitted() {
+    listCommitted.onNext(Unit)
+  }
+
+  fun isListCommitted(): Boolean = listCommitted.value != null
+
   private fun handleScrollPositionRequest(
     request: ScrollToPositionRequest,
     recyclerView: RecyclerView
@@ -87,28 +114,6 @@ class ScrollToPositionDelegate private constructor(
     }
   }
 
-  /**
-   * Entry point for requesting a specific scroll position.
-   */
-  fun requestScrollPosition(position: Int, smooth: Boolean = true) {
-    scrollPositionRequested.onNext(ScrollToPositionRequest(position, smooth))
-  }
-
-  /**
-   * Reset the scroll position to 0
-   */
-  fun resetScrollPosition() {
-    requestScrollPosition(0, true)
-    recyclerView.requestLayout()
-  }
-
-  /**
-   * This should be called every time a list is submitted to the RecyclerView's adapter.
-   */
-  fun notifyListCommitted() {
-    listCommitted.onNext(Unit)
-  }
-
   private data class ScrollToPositionRequest(
     val position: Int,
     val smooth: Boolean

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

@@ -402,6 +402,39 @@ public class ConversationAdapter
     }
   }
 
+  /**
+   * Checks a range around the given position for nulls.
+   *
+   * @param position The position we wish to jump to.
+   * @return true if we seem like we've paged in the right data, false if not so.
+   */
+  public boolean canJumpToPosition(int position) {
+    position = isTypingViewEnabled() ? position - 1 : position;
+    if (position < 0) {
+      return false;
+    }
+
+    if (position > super.getItemCount()) {
+      Log.d(TAG, "Could not access corrected position " + position + " as it is out of bounds.");
+      return false;
+    }
+
+    int start = Math.max(position - 10, 0);
+    int end = Math.min(position + 5, super.getItemCount());
+
+    for (int i = start; i < end; i++) {
+      if (super.getItem(i) == null) {
+        if (pagingController != null) {
+          pagingController.onDataNeededAroundIndex(position);
+        }
+
+        return false;
+      }
+    }
+
+    return true;
+  }
+
   public void setPagingController(@Nullable PagingController pagingController) {
     this.pagingController = pagingController;
   }
@@ -431,7 +464,7 @@ public class ConversationAdapter
    * an adjusted message position based on adapter state.
    */
   @MainThread
-  int getAdapterPositionForMessagePosition(int messagePosition) {
+  public int getAdapterPositionForMessagePosition(int messagePosition) {
     return isTypingViewEnabled() ? messagePosition + 1 : messagePosition;
   }
 
@@ -580,7 +613,7 @@ public class ConversationAdapter
    * Provided a pool, this will initialize it with view counts that make sense.
    */
   @MainThread
-  static void initializePool(@NonNull RecyclerView.RecycledViewPool pool) {
+  public static void initializePool(@NonNull RecyclerView.RecycledViewPool pool) {
     pool.setMaxRecycledViews(MESSAGE_TYPE_INCOMING_TEXT, 25);
     pool.setMaxRecycledViews(MESSAGE_TYPE_INCOMING_MULTIMEDIA, 15);
     pool.setMaxRecycledViews(MESSAGE_TYPE_OUTGOING_TEXT, 25);

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

@@ -22,6 +22,15 @@ data class ConversationData(
     return lastSeenPosition > 0
   }
 
+  fun getStartPosition(): Int {
+    return when {
+      shouldJumpToMessage() -> jumpToPosition
+      messageRequestData.isMessageRequestAccepted && shouldScrollToLastSeen() -> lastSeenPosition
+      messageRequestData.isMessageRequestAccepted -> lastScrolledPosition
+      else -> threadSize
+    }
+  }
+
   data class MessageRequestData @JvmOverloads constructor(
     val isMessageRequestAccepted: Boolean,
     val isHidden: Boolean,

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

@@ -115,6 +115,7 @@ import org.thoughtcrime.securesms.conversation.quotes.MessageQuotesBottomSheet;
 import org.thoughtcrime.securesms.conversation.ui.edit.EditMessageHistoryDialog;
 import org.thoughtcrime.securesms.conversation.ui.error.EnableCallNotificationSettingsDialog;
 import org.thoughtcrime.securesms.conversation.v2.AddToContactsContract;
+import org.thoughtcrime.securesms.conversation.v2.BubbleLayoutTransitionListener;
 import org.thoughtcrime.securesms.database.DatabaseObserver;
 import org.thoughtcrime.securesms.database.MessageTable;
 import org.thoughtcrime.securesms.database.SignalDatabase;
@@ -258,8 +259,6 @@ public class ConversationFragment extends LoggingFragment implements Multiselect
   private OnScrollListener            conversationScrollListener;
   private int                         lastSeenScrollOffset;
   private Stopwatch                   startupStopwatch;
-  private LayoutTransition            layoutTransition;
-  private TransitionListener          transitionListener;
   private View                        reactionsShade;
   private SignalBottomActionBar       bottomActionBar;
   private OpenableGiftItemDecoration  openableGiftItemDecoration;
@@ -309,8 +308,8 @@ public class ConversationFragment extends LoggingFragment implements Multiselect
     list           = view.findViewById(android.R.id.list);
     composeDivider = view.findViewById(R.id.compose_divider);
 
-    layoutTransition   = new LayoutTransition();
-    transitionListener = new TransitionListener(list);
+    BubbleLayoutTransitionListener bubbleLayoutTransitionListener = new BubbleLayoutTransitionListener(list);
+    getViewLifecycleOwner().getLifecycle().addObserver(bubbleLayoutTransitionListener);
 
     scrollToBottomButton  = view.findViewById(R.id.scroll_to_bottom);
     scrollToMentionButton = view.findViewById(R.id.scroll_to_mention);
@@ -514,7 +513,6 @@ public class ConversationFragment extends LoggingFragment implements Multiselect
     super.onStart();
     initializeTypingObserver();
     SignalProxyUtil.startListeningToWebsocket();
-    layoutTransition.getAnimator(LayoutTransition.CHANGE_DISAPPEARING).addListener(transitionListener);
   }
 
   @Override
@@ -538,7 +536,6 @@ public class ConversationFragment extends LoggingFragment implements Multiselect
   public void onStop() {
     super.onStop();
     ApplicationDependencies.getTypingStatusRepository().getTypists(threadId).removeObservers(getViewLifecycleOwner());
-    layoutTransition.getAnimator(LayoutTransition.CHANGE_DISAPPEARING).removeListener(transitionListener);
   }
 
   @Override
@@ -2396,34 +2393,4 @@ public class ConversationFragment extends LoggingFragment implements Multiselect
       }, 400);
     }
   }
-
-  private static final class TransitionListener implements Animator.AnimatorListener {
-
-    private final ValueAnimator animator = ValueAnimator.ofFloat(0f, 1f);
-
-    TransitionListener(RecyclerView recyclerView) {
-      animator.addUpdateListener(unused -> recyclerView.invalidate());
-      animator.setDuration(100L);
-    }
-
-    @Override
-    public void onAnimationStart(Animator animation) {
-      animator.start();
-    }
-
-    @Override
-    public void onAnimationEnd(Animator animation) {
-      animator.end();
-    }
-
-    @Override
-    public void onAnimationCancel(Animator animation) {
-      // Do Nothing
-    }
-
-    @Override
-    public void onAnimationRepeat(Animator animation) {
-      // Do Nothing
-    }
-  }
 }

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

@@ -0,0 +1,47 @@
+package org.thoughtcrime.securesms.conversation.v2
+
+import android.animation.Animator
+import android.animation.LayoutTransition
+import android.animation.ValueAnimator
+import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.LifecycleOwner
+import androidx.recyclerview.widget.RecyclerView
+
+class BubbleLayoutTransitionListener(
+  recyclerView: RecyclerView
+) : DefaultLifecycleObserver {
+
+  private val layoutTransition = LayoutTransition()
+  private val transitionListener = TransitionListener(recyclerView)
+
+  override fun onStart(owner: LifecycleOwner) {
+    super.onStart(owner)
+    layoutTransition.getAnimator(LayoutTransition.CHANGE_DISAPPEARING).addListener(transitionListener)
+  }
+
+  override fun onStop(owner: LifecycleOwner) {
+    super.onStop(owner)
+    layoutTransition.getAnimator(LayoutTransition.CHANGE_DISAPPEARING).removeListener(transitionListener)
+  }
+
+  private class TransitionListener(recyclerView: RecyclerView) : Animator.AnimatorListener {
+    private val animator = ValueAnimator.ofFloat(0f, 1f)
+
+    init {
+      animator.addUpdateListener { recyclerView.invalidate() }
+      animator.duration = 100L
+    }
+
+    override fun onAnimationStart(animation: Animator) {
+      animator.start()
+    }
+
+    override fun onAnimationEnd(animation: Animator) {
+      animator.end()
+    }
+
+    override fun onAnimationCancel(animation: Animator) = Unit
+
+    override fun onAnimationRepeat(animation: Animator) = Unit
+  }
+}

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

@@ -32,6 +32,7 @@ import org.thoughtcrime.securesms.MainActivity
 import org.thoughtcrime.securesms.R
 import org.thoughtcrime.securesms.badges.gifts.viewgift.received.ViewReceivedGiftBottomSheet
 import org.thoughtcrime.securesms.badges.gifts.viewgift.sent.ViewSentGiftBottomSheet
+import org.thoughtcrime.securesms.components.ScrollToPositionDelegate
 import org.thoughtcrime.securesms.components.ViewBinderDelegate
 import org.thoughtcrime.securesms.components.recyclerview.SmoothScrollingLinearLayoutManager
 import org.thoughtcrime.securesms.components.voice.VoiceNoteMediaControllerOwner
@@ -48,6 +49,7 @@ import org.thoughtcrime.securesms.conversation.ConversationOptionsMenu
 import org.thoughtcrime.securesms.conversation.MarkReadHelper
 import org.thoughtcrime.securesms.conversation.colors.Colorizer
 import org.thoughtcrime.securesms.conversation.colors.RecyclerViewColorizer
+import org.thoughtcrime.securesms.conversation.mutiselect.ConversationItemAnimator
 import org.thoughtcrime.securesms.conversation.mutiselect.MultiselectItemDecoration
 import org.thoughtcrime.securesms.conversation.mutiselect.MultiselectPart
 import org.thoughtcrime.securesms.conversation.v2.groups.ConversationGroupCallViewModel
@@ -56,6 +58,7 @@ import org.thoughtcrime.securesms.database.model.InMemoryMessageRecord
 import org.thoughtcrime.securesms.database.model.MessageRecord
 import org.thoughtcrime.securesms.database.model.MmsMessageRecord
 import org.thoughtcrime.securesms.databinding.V2ConversationFragmentBinding
+import org.thoughtcrime.securesms.dependencies.ApplicationDependencies
 import org.thoughtcrime.securesms.giph.mp4.GiphyMp4ItemDecoration
 import org.thoughtcrime.securesms.giph.mp4.GiphyMp4PlaybackController
 import org.thoughtcrime.securesms.giph.mp4.GiphyMp4PlaybackPolicy
@@ -89,6 +92,7 @@ import org.thoughtcrime.securesms.util.ContextUtil
 import org.thoughtcrime.securesms.util.DrawableUtil
 import org.thoughtcrime.securesms.util.FullscreenHelper
 import org.thoughtcrime.securesms.util.WindowUtil
+import org.thoughtcrime.securesms.util.doAfterNextLayout
 import org.thoughtcrime.securesms.util.fragments.requireListener
 import org.thoughtcrime.securesms.util.hasGiftBadge
 import org.thoughtcrime.securesms.util.visible
@@ -145,8 +149,12 @@ class ConversationFragment : LoggingFragment(R.layout.v2_conversation_fragment)
     FullscreenHelper(requireActivity()).showSystemUI()
 
     layoutManager = SmoothScrollingLinearLayoutManager(requireContext(), true)
+    binding.conversationItemRecycler.setHasFixedSize(false)
     binding.conversationItemRecycler.layoutManager = layoutManager
 
+    val layoutTransitionListener = BubbleLayoutTransitionListener(binding.conversationItemRecycler)
+    viewLifecycleOwner.lifecycle.addObserver(layoutTransitionListener)
+
     val recyclerViewColorizer = RecyclerViewColorizer(binding.conversationItemRecycler)
     recyclerViewColorizer.setChatColors(args.chatColors)
 
@@ -174,6 +182,10 @@ class ConversationFragment : LoggingFragment(R.layout.v2_conversation_fragment)
         presentConversationTitle(it)
       })
 
+    disposables += viewModel.markReadRequests
+      .observeOn(AndroidSchedulers.mainThread())
+      .subscribeBy(onNext = markReadHelper::onViewsRevealed)
+
     EventBus.getDefault().registerForLifecycle(groupCallViewModel, viewLifecycleOwner)
     presentGroupCallJoinButton()
   }
@@ -184,6 +196,15 @@ class ConversationFragment : LoggingFragment(R.layout.v2_conversation_fragment)
     WindowUtil.setLightNavigationBarFromTheme(requireActivity())
     WindowUtil.setLightStatusBarFromTheme(requireActivity())
     groupCallViewModel.peekGroupCall()
+
+    if (!args.conversationScreenType.isInBubble) {
+      ApplicationDependencies.getMessageNotifier().setVisibleThread(ConversationId.forConversation(args.threadId))
+    }
+  }
+
+  override fun onPause() {
+    super.onPause()
+    ApplicationDependencies.getMessageNotifier().clearVisibleThread()
   }
 
   private fun registerForResults() {
@@ -204,23 +225,50 @@ class ConversationFragment : LoggingFragment(R.layout.v2_conversation_fragment)
       colorizer
     )
 
+    val scrollToPositionDelegate = ScrollToPositionDelegate(
+      binding.conversationItemRecycler,
+      adapter::canJumpToPosition,
+      adapter::getAdapterPositionForMessagePosition
+    )
+
+    binding.conversationItemRecycler.itemAnimator = ConversationItemAnimator(
+      isInMultiSelectMode = adapter.selectedItems::isNotEmpty,
+      shouldPlayMessageAnimations = {
+        scrollToPositionDelegate.isListCommitted() && binding.conversationItemRecycler.scrollState == RecyclerView.SCROLL_STATE_IDLE
+      },
+      isParentFilled = {
+        binding.conversationItemRecycler.canScrollVertically(1) || binding.conversationItemRecycler.canScrollVertically(-1)
+      }
+    )
+
+    ConversationAdapter.initializePool(binding.conversationItemRecycler.recycledViewPool)
     adapter.setPagingController(viewModel.pagingController)
+    adapter.registerAdapterDataObserver(DataObserver(scrollToPositionDelegate))
     viewLifecycleOwner.lifecycle.addObserver(LastSeenPositionUpdater(adapter, layoutManager, viewModel))
     binding.conversationItemRecycler.adapter = adapter
     giphyMp4ProjectionRecycler = initializeGiphyMp4()
 
-    binding.conversationItemRecycler.addItemDecoration(
-      MultiselectItemDecoration(
+    val multiselectItemDecoration = MultiselectItemDecoration(
       requireContext()
     ) { viewModel.wallpaperSnapshot }
-    )
+
+    binding.conversationItemRecycler.addItemDecoration(multiselectItemDecoration)
+    viewLifecycleOwner.lifecycle.addObserver(multiselectItemDecoration)
+
+    disposables += viewModel.conversationThreadState.subscribeBy {
+      scrollToPositionDelegate.requestScrollPosition(it.meta.getStartPosition(), false)
+    }
 
     disposables += viewModel
       .conversationThreadState
-      .flatMap { it.items.data }
+      .flatMapObservable { it.items.data }
       .observeOn(AndroidSchedulers.mainThread())
       .subscribeBy(onNext = {
-        adapter.submitList(it)
+        adapter.submitList(it) {
+          binding.conversationItemRecycler.doAfterNextLayout {
+            scrollToPositionDelegate.notifyListCommitted()
+          }
+        }
       })
 
     disposables += viewModel
@@ -231,6 +279,13 @@ class ConversationFragment : LoggingFragment(R.layout.v2_conversation_fragment)
         adapter.notifyItemRangeChanged(0, adapter.itemCount)
       })
 
+    binding.conversationItemRecycler.addOnScrollListener(object : RecyclerView.OnScrollListener() {
+      override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
+        val timestamp = MarkReadHelper.getLatestTimestamp(adapter, layoutManager)
+        timestamp.ifPresent(viewModel::requestMarkRead)
+      }
+    })
+
     presentActionBarMenu()
   }
 
@@ -353,6 +408,18 @@ class ConversationFragment : LoggingFragment(R.layout.v2_conversation_fragment)
     return callback
   }
 
+  private inner class DataObserver(
+    private val scrollToPositionDelegate: ScrollToPositionDelegate
+  ) : RecyclerView.AdapterDataObserver() {
+    override fun onItemRangeInserted(positionStart: Int, itemCount: Int) {
+      Log.d(TAG, "onItemRangeInserted $positionStart $itemCount")
+      if (positionStart == 0 && itemCount == 1 && !binding.conversationItemRecycler.canScrollVertically(1)) {
+        Log.d(TAG, "Requesting scroll to bottom.")
+        scrollToPositionDelegate.resetScrollPosition()
+      }
+    }
+  }
+
   private inner class ConversationItemClickListener : ConversationAdapter.ItemClickListener {
     override fun onQuoteClicked(messageRecord: MmsMessageRecord?) {
       // TODO [alex] - ("Not yet implemented")

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

@@ -11,10 +11,8 @@ import org.signal.paging.PagingConfig
 import org.thoughtcrime.securesms.conversation.ConversationDataSource
 import org.thoughtcrime.securesms.conversation.colors.GroupAuthorNameColorHelper
 import org.thoughtcrime.securesms.conversation.colors.NameColor
-import org.thoughtcrime.securesms.database.DatabaseObserver
 import org.thoughtcrime.securesms.database.SignalDatabase
 import org.thoughtcrime.securesms.database.SignalDatabase.Companion.threads
-import org.thoughtcrime.securesms.dependencies.ApplicationDependencies
 import org.thoughtcrime.securesms.recipients.Recipient
 import org.thoughtcrime.securesms.recipients.RecipientId
 import kotlin.math.max
@@ -50,16 +48,10 @@ class ConversationRepository(context: Context) {
    * Loads the details necessary to display the conversation thread.
    */
   fun getConversationThreadState(threadId: Long, requestedStartPosition: Int): Single<ConversationThreadState> {
-    return Single.create { emitter ->
-      val recipient = SignalDatabase.threads.getRecipientForThreadId(threadId)!!
+    return Single.fromCallable {
+      val recipient = threads.getRecipientForThreadId(threadId)!!
       val metadata = oldConversationRepository.getConversationData(threadId, recipient, requestedStartPosition)
       val messageRequestData = metadata.messageRequestData
-      val startPosition = when {
-        metadata.shouldJumpToMessage() -> metadata.jumpToPosition
-        messageRequestData.isMessageRequestAccepted && metadata.shouldScrollToLastSeen() -> metadata.lastSeenPosition
-        messageRequestData.isMessageRequestAccepted -> metadata.lastScrolledPosition
-        else -> metadata.threadSize
-      }
       val dataSource = ConversationDataSource(
         applicationContext,
         threadId,
@@ -69,36 +61,13 @@ class ConversationRepository(context: Context) {
       )
       val config = PagingConfig.Builder().setPageSize(25)
         .setBufferPages(2)
-        .setStartIndex(max(startPosition, 0))
+        .setStartIndex(max(metadata.getStartPosition(), 0))
         .build()
 
-      val threadState = ConversationThreadState(
+      ConversationThreadState(
         items = PagedData.createForObservable(dataSource, config),
         meta = metadata
       )
-
-      val controller = threadState.items.controller
-      val messageUpdateObserver = DatabaseObserver.MessageObserver {
-        controller.onDataItemChanged(it)
-      }
-      val messageInsertObserver = DatabaseObserver.MessageObserver {
-        controller.onDataItemInserted(it, 0)
-      }
-      val conversationObserver = DatabaseObserver.Observer {
-        controller.onDataInvalidated()
-      }
-
-      ApplicationDependencies.getDatabaseObserver().registerMessageUpdateObserver(messageUpdateObserver)
-      ApplicationDependencies.getDatabaseObserver().registerMessageInsertObserver(threadId, messageInsertObserver)
-      ApplicationDependencies.getDatabaseObserver().registerConversationObserver(threadId, conversationObserver)
-
-      emitter.setCancellable {
-        ApplicationDependencies.getDatabaseObserver().unregisterObserver(messageUpdateObserver)
-        ApplicationDependencies.getDatabaseObserver().unregisterObserver(messageInsertObserver)
-        ApplicationDependencies.getDatabaseObserver().unregisterObserver(conversationObserver)
-      }
-
-      emitter.onSuccess(threadState)
     }
   }
 

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

@@ -2,18 +2,23 @@ package org.thoughtcrime.securesms.conversation.v2
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
+import io.reactivex.rxjava3.core.Flowable
 import io.reactivex.rxjava3.core.Observable
+import io.reactivex.rxjava3.core.Single
 import io.reactivex.rxjava3.disposables.CompositeDisposable
 import io.reactivex.rxjava3.kotlin.plusAssign
 import io.reactivex.rxjava3.kotlin.subscribeBy
+import io.reactivex.rxjava3.processors.PublishProcessor
 import io.reactivex.rxjava3.subjects.BehaviorSubject
 import io.reactivex.rxjava3.subjects.Subject
 import org.signal.paging.ProxyPagingController
 import org.thoughtcrime.securesms.conversation.ConversationIntents.Args
 import org.thoughtcrime.securesms.conversation.colors.GroupAuthorNameColorHelper
 import org.thoughtcrime.securesms.conversation.colors.NameColor
+import org.thoughtcrime.securesms.database.DatabaseObserver
 import org.thoughtcrime.securesms.database.model.MessageId
 import org.thoughtcrime.securesms.database.model.MessageRecord
+import org.thoughtcrime.securesms.dependencies.ApplicationDependencies
 import org.thoughtcrime.securesms.recipients.Recipient
 import org.thoughtcrime.securesms.recipients.RecipientId
 import org.thoughtcrime.securesms.util.hasGiftBadge
@@ -35,7 +40,12 @@ class ConversationViewModel(
   val recipient: Observable<Recipient> = _recipient
 
   private val _conversationThreadState: Subject<ConversationThreadState> = BehaviorSubject.create()
-  val conversationThreadState: Observable<ConversationThreadState> = _conversationThreadState
+  val conversationThreadState: Single<ConversationThreadState> = _conversationThreadState.firstOrError()
+
+  private val _markReadProcessor: PublishProcessor<Long> = PublishProcessor.create()
+  val markReadRequests: Flowable<Long> = _markReadProcessor
+    .onBackpressureBuffer()
+    .distinct()
 
   val pagingController = ProxyPagingController<MessageId>()
 
@@ -56,6 +66,31 @@ class ConversationViewModel(
         pagingController.set(it.items.controller)
         _conversationThreadState.onNext(it)
       })
+
+    disposables += _conversationThreadState.firstOrError().flatMapObservable { threadState ->
+      Observable.create<Unit> { emitter ->
+        val controller = threadState.items.controller
+        val messageUpdateObserver = DatabaseObserver.MessageObserver {
+          controller.onDataItemChanged(it)
+        }
+        val messageInsertObserver = DatabaseObserver.MessageObserver {
+          controller.onDataItemInserted(it, 0)
+        }
+        val conversationObserver = DatabaseObserver.Observer {
+          controller.onDataInvalidated()
+        }
+
+        ApplicationDependencies.getDatabaseObserver().registerMessageUpdateObserver(messageUpdateObserver)
+        ApplicationDependencies.getDatabaseObserver().registerMessageInsertObserver(threadId, messageInsertObserver)
+        ApplicationDependencies.getDatabaseObserver().registerConversationObserver(threadId, conversationObserver)
+
+        emitter.setCancellable {
+          ApplicationDependencies.getDatabaseObserver().unregisterObserver(messageUpdateObserver)
+          ApplicationDependencies.getDatabaseObserver().unregisterObserver(messageInsertObserver)
+          ApplicationDependencies.getDatabaseObserver().unregisterObserver(conversationObserver)
+        }
+      }
+    }.subscribe()
   }
 
   override fun onCleared() {
@@ -75,6 +110,9 @@ class ConversationViewModel(
     }
   }
 
+  fun requestMarkRead(timestamp: Long) {
+  }
+
   class Factory(
     private val args: Args,
     private val repository: ConversationRepository

app/src/main/res/layout/v2_conversation_fragment.xml

@@ -37,9 +37,14 @@
     <org.thoughtcrime.securesms.conversation.mutiselect.MultiselectRecyclerView
         android:id="@+id/conversation_item_recycler"
         android:layout_width="match_parent"
-        android:layout_height="0dp"
-        app:layout_constraintBottom_toTopOf="@+id/conversation_bottom_panel_barrier"
+        android:layout_height="0dip"
+        android:clipChildren="false"
+        android:clipToPadding="false"
+        android:overScrollMode="ifContentScrolls"
+        android:scrollbars="vertical"
+        android:splitMotionEvents="false"
         app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintBottom_toTopOf="@id/conversation_bottom_panel_barrier"
         tools:itemCount="20"
         tools:listitem="@layout/conversation_item_sent_text_only" />
 
@@ -94,10 +99,10 @@
 
     <androidx.constraintlayout.widget.Barrier
         android:id="@+id/conversation_bottom_panel_barrier"
-        app:barrierDirection="top"
-        app:constraint_referenced_ids="conversation_input_panel"
         android:layout_width="wrap_content"
-        android:layout_height="wrap_content" />
+        android:layout_height="wrap_content"
+        app:barrierDirection="top"
+        app:constraint_referenced_ids="conversation_input_panel" />
 
     <include
         android:id="@+id/conversation_input_panel"