tai/research/tui-framework-design/telegram-android-chat-message-cell.md

Telegram Android ChatMessageCell — bubble grouping, tails, in-bubble metadata

Metadata

Field	Value
Institute	Molodetz Institute — Research & Retrieval Division
Subject	tui-framework-design
Document type	Source Dossier
Tier	1
Source title	ChatMessageCell.java (Telegram Android message cell)
Source URL	https://raw.githubusercontent.com/DrKLO/Telegram/master/TMessagesProj/src/main/java/org/telegram/ui/Cells/ChatMessageCell.java
Source publisher / author	Telegram (DrKLO/Telegram, official Android client)
Source type	repository
Source date (published)	Unknown — not stated
Date researched	2026-10-11
Researched by	tai (agent), model: Muse Spark, on behalf of retoor
Research method	direct page fetch
Confidence	High
Status	Active

Summary

The actual Android implementation of message grouping and in-bubble metadata: consecutive same-sender messages join via position flags with squared inner corners, the tail appears only on the last message of a group, and the timestamp sits at the bubble's bottom-right with the sender's checks immediately after.

Key findings

• Joined message groups use POSITION_FLAG top/bottom/left/right combinations; inner (joined) corners are squared.
• The bubble tail renders only on the last message of a consecutive same-sender group.
• Timestamp is bottom-right inside the bubble (timeX = backgroundWidth - dp(4) - timeWidth); on own messages the checks render immediately after the time.
• Group sender names are header-colored from the 8-hue peer palette.
• Incoming bubbles sit left, outgoing right; the in/out key split holds across clients.

Pros / strengths

• Ground-truth grouping and tail logic straight from the shipped renderer.
• Exact time-placement formula leaves no ambiguity about metadata position.

Cons / limitations / caveats

• Android only; tail side, corner radii, paddings, and inter-message spacing per client were not captured (open gap).
• Media-bubble time-overlay details were not captured (open gap).
• The class is large; only the grouping/tail/metadata subset was synthesized.

Relevance to tai

Defines the grouping grammar tai keeps even without bubbles (join consecutive same-sender rows, metadata at the row's trailing end, peer-hue sender names) and the bubble geometry tai deliberately does not need.

Changelog

Date	Change
2026-10-11	Initial dossier created.