Add date headers to CFv2.

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

@@ -326,6 +326,7 @@ class ConversationFragment : LoggingFragment(R.layout.v2_conversation_fragment)
   private lateinit var multiselectItemDecoration: MultiselectItemDecoration
   private lateinit var openableGiftItemDecoration: OpenableGiftItemDecoration
   private lateinit var threadHeaderMarginDecoration: ThreadHeaderMarginDecoration
+  private lateinit var dateHeaderDecoration: DateHeaderDecoration
 
   private var animationsAllowed = false
   private var actionMode: ActionMode? = null
@@ -464,6 +465,7 @@ class ConversationFragment : LoggingFragment(R.layout.v2_conversation_fragment)
 
         adapter.submitList(it) {
           scrollToPositionDelegate.notifyListCommitted()
+          dateHeaderDecoration.currentItems = it
 
           if (firstRender) {
             firstRender = false
@@ -785,6 +787,7 @@ class ConversationFragment : LoggingFragment(R.layout.v2_conversation_fragment)
     binding.conversationDisabledInput.setWallpaperEnabled(wallpaperEnabled)
 
     adapter.onHasWallpaperChanged(wallpaperEnabled)
+    dateHeaderDecoration.hasWallpaper = wallpaperEnabled
   }
 
   private fun presentChatColors(chatColors: ChatColors) {
@@ -909,6 +912,9 @@ class ConversationFragment : LoggingFragment(R.layout.v2_conversation_fragment)
 
     threadHeaderMarginDecoration = ThreadHeaderMarginDecoration()
     binding.conversationItemRecycler.addItemDecoration(threadHeaderMarginDecoration)
+
+    dateHeaderDecoration = DateHeaderDecoration(hasWallpaper = args.wallpaper != null)
+    binding.conversationItemRecycler.addItemDecoration(dateHeaderDecoration, 0)
   }
 
   private fun initializeGiphyMp4(): GiphyMp4ProjectionRecycler {

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

@@ -0,0 +1,149 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.thoughtcrime.securesms.conversation.v2
+
+import android.graphics.Canvas
+import android.graphics.Rect
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.TextView
+import androidx.core.content.ContextCompat
+import androidx.recyclerview.widget.RecyclerView
+import org.thoughtcrime.securesms.R
+import org.thoughtcrime.securesms.conversation.v2.data.ConversationMessageElement
+import org.thoughtcrime.securesms.database.model.MediaMmsMessageRecord
+import org.thoughtcrime.securesms.util.DateUtils
+import org.thoughtcrime.securesms.util.adapter.mapping.MappingModel
+import org.thoughtcrime.securesms.util.toLocalDate
+import java.util.Locale
+
+private typealias ConversationElement = MappingModel<*>
+
+/**
+ * Given the same list as used by the [ConversationAdapterV2], determines where date headers should be rendered
+ * and manages adjusting the list accordingly.
+ *
+ * This is a converted and trimmed down version of [org.thoughtcrime.securesms.util.StickyHeaderDecoration].
+ */
+class DateHeaderDecoration(hasWallpaper: Boolean = false, private val scheduleMessageMode: Boolean = false) : RecyclerView.ItemDecoration() {
+
+  private val headerCache: MutableMap<Long, DateHeaderViewHolder> = hashMapOf()
+
+  var currentItems: MutableList<ConversationElement?> = mutableListOf()
+
+  var hasWallpaper: Boolean = hasWallpaper
+    set(value) {
+      field = value
+      headerCache.values.forEach { it.updateForWallpaper() }
+    }
+
+  override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
+    val position = parent.getChildAdapterPosition(view)
+
+    val headerHeight = if (position in currentItems.indices && hasHeader(position)) {
+      getHeader(parent, currentItems[position] as ConversationMessageElement).height
+    } else {
+      0
+    }
+
+    outRect.set(0, headerHeight, 0, 0)
+  }
+
+  override fun onDrawOver(c: Canvas, parent: RecyclerView, state: RecyclerView.State) {
+    val count = parent.childCount
+    for (layoutPosition in 0 until count) {
+      val child = parent.getChildAt(parent.childCount - 1 - layoutPosition)
+      val position = parent.getChildAdapterPosition(child)
+
+      if (hasHeader(position)) {
+        val headerView = getHeader(parent, currentItems[position] as ConversationMessageElement).itemView
+        c.save()
+        val left = parent.left
+        val top = child.y.toInt() - headerView.height
+        c.translate(left.toFloat(), top.toFloat())
+        headerView.draw(c)
+        c.restore()
+      }
+    }
+  }
+
+  private fun hasHeader(position: Int): Boolean {
+    val model = currentItems[position]
+
+    if (model == null || model !is ConversationMessageElement) {
+      return false
+    }
+
+    val previousPosition = position + 1
+    val previousDay: Long
+    if (previousPosition in currentItems.indices) {
+      val previousModel = currentItems[previousPosition]
+      if (previousModel == null || previousModel !is ConversationMessageElement) {
+        return true
+      } else {
+        previousDay = previousModel.toEpochDay()
+      }
+    } else {
+      return false
+    }
+
+    return model.toEpochDay() != previousDay
+  }
+
+  private fun getHeader(parent: RecyclerView, model: ConversationMessageElement): DateHeaderViewHolder {
+    val headerHolder: DateHeaderViewHolder = headerCache.getOrPut(model.toEpochDay()) {
+      val view = LayoutInflater.from(parent.context).inflate(R.layout.conversation_item_header, parent, false)
+      val holder = DateHeaderViewHolder(view)
+      holder.bind(model)
+      holder
+    }
+
+    val headerView = headerHolder.itemView
+    val widthSpec = View.MeasureSpec.makeMeasureSpec(parent.width, View.MeasureSpec.EXACTLY)
+    val heightSpec = View.MeasureSpec.makeMeasureSpec(parent.height, View.MeasureSpec.UNSPECIFIED)
+    val childWidth = ViewGroup.getChildMeasureSpec(widthSpec, parent.paddingLeft + parent.paddingRight, headerView.layoutParams.width)
+    val childHeight = ViewGroup.getChildMeasureSpec(heightSpec, parent.paddingTop + parent.paddingBottom, headerView.layoutParams.height)
+    headerView.measure(childWidth, childHeight)
+    headerView.layout(0, 0, headerView.measuredWidth, headerView.measuredHeight)
+    return headerHolder
+  }
+
+  private fun ConversationMessageElement.timestamp(): Long {
+    return if (scheduleMessageMode) {
+      (conversationMessage.messageRecord as MediaMmsMessageRecord).scheduledDate
+    } else {
+      conversationMessage.messageRecord.dateSent
+    }
+  }
+
+  private fun ConversationMessageElement.toEpochDay(): Long {
+    return timestamp().toLocalDate().toEpochDay()
+  }
+
+  private inner class DateHeaderViewHolder(val itemView: View) {
+    private val date = itemView.findViewById<TextView>(R.id.text)
+
+    val height: Int
+      get() = itemView.height
+
+    fun bind(model: ConversationMessageElement) {
+      val dateText = DateUtils.getConversationDateHeaderString(itemView.context, Locale.getDefault(), model.timestamp())
+      date.text = dateText
+      updateForWallpaper()
+    }
+
+    fun updateForWallpaper() {
+      if (hasWallpaper) {
+        date.setBackgroundResource(R.drawable.wallpaper_bubble_background_18)
+        date.setTextColor(ContextCompat.getColor(itemView.context, R.color.signal_colorNeutralInverse))
+      } else {
+        date.background = null
+        date.setTextColor(ContextCompat.getColor(itemView.context, R.color.signal_colorOnSurfaceVariant))
+      }
+    }
+  }
+}

app/src/main/java/org/thoughtcrime/securesms/util/JavaTimeExtensions.kt

@@ -5,6 +5,7 @@ import android.os.Build
 import android.text.format.DateFormat
 import java.time.DayOfWeek
 import java.time.Instant
+import java.time.LocalDate
 import java.time.LocalDateTime
 import java.time.LocalTime
 import java.time.OffsetDateTime
@@ -68,6 +69,13 @@ fun Long.toLocalDateTime(zoneId: ZoneId = ZoneId.systemDefault()): LocalDateTime
   return LocalDateTime.ofInstant(Instant.ofEpochMilli(this), zoneId)
 }
 
+/**
+ * Convert milliseconds to local date with provided [zoneId].
+ */
+fun Long.toLocalDate(zoneId: ZoneId = ZoneId.systemDefault()): LocalDate {
+  return Instant.ofEpochMilli(this).atZone(zoneId).toLocalDate()
+}
+
 /**
  * Convert milliseconds to local date time with provided [zoneId].
  */