Re:Dollars — Android

Native Android client for Bangumi Dollars, the realtime chat room on Bangumi. Kotlin + Jetpack Compose + Material 3.

Reading and realtime updates go through the re-dollars-backend service; posting goes directly to Bangumi using your logged-in session, the same way the re-dollars-preact userscript does. See ANDROID_APP_SPEC.md for the full technical spec this app was built from.

Features

• Live message stream over WebSocket, with REST-backed history/scrollback and gap recovery on reconnect
• Sending messages with optimistic bubbles, send/confirm, and retry on failure
• Replies (quote), reactions, edit/delete for your own messages
• BBCode rendering: text styles, links, [user] mentions, [quote], [img]/[video]/[audio], [code], [mask] spoilers, smilies, and BMO emoji
• Image lightbox, media gallery, in-app search
• Presence (online count, typing indicators), push notifications (FCM), voice message recording
• Per-user blocking, account sheet, Material 3 theming with dynamic color and light/dark support

Requirements

• Android Studio (current stable)
• JDK 17
• Android SDK: minSdk 26, targetSdk 36, compileSdk 37

Setup

1. Open the re-dollars-Android/ directory in Android Studio and let it sync Gradle.
2. Push notifications require Firebase: drop your own app/google-services.json in place of/next to the existing one, or leave it as-is if you're not touching FCM. The build stays green either way (the google-services plugin is only applied if the file exists).
3. Release builds are signed using release.keystore at the project root, with credentials from local.properties (RELEASE_STORE_PASSWORD, RELEASE_KEY_ALIAS, RELEASE_KEY_PASSWORD) or the matching environment variables. Not needed for debug builds.
4. Backend/auth endpoints are hardcoded in Config.kt — edit there to point at a different backend or Bangumi host.

Build & run

./gradlew assembleDebug      # debug APK
./gradlew installDebug       # install on a connected device/emulator
./gradlew assembleRelease    # signed release APK

Authentication

There's no separate account system — login happens inside an in-app WebView against Bangumi itself (bgm.tv), and posting reuses that browser session (cookies + formhash). A second, one-time login via rymk-auth obtains a backend JWT, needed for reactions, edit/delete, read state, uploads, and push registration. See §3 of the spec for details.

Architecture

MVVM with a single-activity Compose UI:

app/src/main/java/mk/ry/redollars/
 ├─ net/       REST client, WebSocket client, models, config, uploads
 ├─ data/      MessageRepository — merges WS events + REST paging + Room cache
 ├─ di/        Hilt modules
 ├─ ui/
 │   ├─ chat/    ChatScreen and its sheets (account, block manager, gallery,
 │   │            notifications, reactions, search, typing indicator, ...)
 │   ├─ render/  BBCode → Compose renderer, image/video/audio, smilies
 │   └─ theme/   Material 3 theme
 ├─ bmo/       BMO emoji codec/renderer (Bangumi's custom emoji system)
 ├─ push/      FCM messaging service
 └─ voice/     Voice message recording

ChatViewModel drives ChatScreen; MessageRepository is the single source of truth, backed by Room and kept in sync by DollarsWs (WebSocket) and RestApi.