SaveSwitcher

SaveSwitcher is an Android app for managing per-user emulator saves by swapping the active save file for a game. Designed to work on small screens e.g. the secondary screen on the Ayn Thor.

Warning

This app was vibe-coded with Codex and performs real file operations on emulator saves. Always back up your saves before using it. Save switching can overwrite, rename, or remove files.

I’m happy to accept issues and pull requests, but this is a quick spare-time project. I can’t guarantee active maintenance. It may be better to fork the project.

What It Does

• Register multiple emulators (name + save folder + extensions)
• Register multiple users
• Recursively scan save directories via Android SAF
• Detect game save groups:
  • base save: game.ext
  • user variant: game_user.ext
• Switch active user per game:
  • archives current base save to the current owner variant
  • restores target user variant as base if present
  • otherwise removes base so emulator can create a fresh save
• Store emulator/user/history data in Room (persists across app restarts)
• Order games by most recently switched first

Current Status

This is an MVP and still rough around the edges.

Implemented:

• Emulator setup via folder picker (SAF)
• User setup
• Save scanning
• Save switching flow
• History tracking
• Persistent local database for core app data

Not yet implemented / limited:

• Advanced conflict handling and rollback UI
• Emulator-specific bundle/file-family handling
• Import/export/backup helper inside app
• Full test coverage

Platform

• Android min SDK: 29 (Android 10+)
• Works on Android 13 (API 33)
• Built with Kotlin + Jetpack Compose + Room

Build (Local)

Prerequisites:

• JDK 17
• Android SDK installed and configured (sdk.dir in local.properties)

Example:

JAVA_HOME=/opt/homebrew/opt/openjdk@17/libexec/openjdk.jdk/Contents/Home \
GRADLE_USER_HOME=$PWD/.gradle-home \
./gradlew assembleDebug

Debug APK output:

• app/build/outputs/apk/debug/app-debug.apk

Usage Notes

1. Add at least one user.
2. Add emulator profile(s) and choose each save folder.
3. Open Games and tap Scan Saves.
4. Choose a game and tap Switch User.
5. Confirm owner/target user.

Before using with real saves:

• Make a full backup copy of your save folders.
• Test with throwaway saves first.

Data and Privacy

• No cloud sync in MVP
• No network service required for app functionality
• Metadata is stored locally in SQLite (Room)
• Save files remain in your selected storage location

Contributing

Issues and PRs are welcome.

Please keep in mind:

• This repository is not guaranteed to be actively maintained.
• If you need guaranteed progress/features, forking may be the best option.

If you open a PR, include:

• what changed
• why it changed
• how you tested it