brarchive-flutter

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A cross-platform GUI tool for converting between Minecraft Bedrock resource/behavior packs (.zip / .mcpack) and the __brarchive format used by the Bedrock engine. Built with Flutter and Material 3, it is the desktop companion to the brarchive-go CLI.

Overview

Bedrock Edition packs ship as .zip or .mcpack archives. Internally, the engine can consume a compact binary container called __brarchive that bundles many small JSON/UI files into a single file with a fixed-size index. This tool performs both directions of that conversion without requiring a command line:

• Pack - extracts an archive, scans for target files (.json, .json5, .ui), serializes them into __brarchive/*.brarchive, removes the originals, and re-zips the result.
• Unpack - extracts an archive, locates every __brarchive/*.brarchive, restores the original files, removes the __brarchive folder, and re-zips the result.

The binary format is little-endian and consists of a 16-byte header (magic, entry count, version), a fixed-size descriptor table (247-byte name slot + offset + length per entry), and a contiguous content section. It is fully compatible with the output of brarchive-go.

Features

• Material 3 design with dynamic color and expressive components
• Light, dark, and system theme modes
• English and Simplified Chinese, with a "follow system" option
• Native file and folder pickers on each platform (no third-party picker dependency)
• Live console output with timestamps during conversion
• Output directory defaults to the system Downloads folder
• Persistent user preferences via shared_preferences

Supported Platforms

Platform	Status	Artifact
Android	Stable	APK
iOS	Unsigned (sideload required)	IPA
Windows	Stable	ZIP
macOS	Stable	ZIP
Linux	Stable	tar.gz

Getting Started

Prerequisites

• Flutter 3.27 or newer (stable channel)
• Android SDK 35+ for Android builds
• Visual Studio 2022 with the "Desktop development with C++" workload for Windows builds

Build from Source

git clone https://github.com/wisebreeze/brarchive-flutter.git
cd brarchive-flutter
flutter pub get

# Android
flutter build apk --release

# Windows
flutter build windows --release

Pre-built binaries for every release are available on the releases page.

Download

Download the latest release for your platform from GitHub Releases. Artifacts are also attached to each successful workflow run on the main branch.

Installation

Platform	File	Instructions
Android	brarchive-android-release.apk	Tap to install. Allow "install from unknown sources" if prompted. Grant storage permission on first launch.
Windows	brarchive-windows-release.zip	Extract and run brarchive.exe. Right-click to create a desktop shortcut.
macOS	brarchive-macos-release.zip	Extract and drag brarchive.app to Applications. Right-click → Open on first launch to bypass Gatekeeper.
Linux	brarchive-linux-release.tar.gz	Extract and run ./brarchive from the bundle directory.
iOS	brarchive-ios-release.ipa	Sideload via AltStore or Sideloadly. Self-signed certificates expire after 7 days.

Usage

1. Launch the app.
2. In the Input file row, tap the browse button and select a .zip or .mcpack file.
3. In the Output directory row, confirm or change the destination (defaults to your Downloads folder).
4. Click Pack to convert a normal pack into the __brarchive format, or Unpack to reverse it.
5. Watch the console panel for progress. The output archive is written to the chosen directory.

Use the overflow menu in the top-right corner to switch language or theme at any time. Selections are remembered across launches.

How It Works

Pack

1. The input archive is extracted in memory.
2. The converter walks the tree, skipping textures, materials, texts, and sounds directories, while descending into subpacks.
3. In each qualifying folder, files with .json, .json5, or .ui extensions are collected (excluding ui/_global_variables.json).
4. Those files are serialized into a single .brarchive blob placed under a new __brarchive/ subfolder, and the originals are deleted.
5. Empty directories are pruned and the tree is re-zipped.

Unpack

1. The input archive is extracted in memory.
2. Every __brarchive/*.brarchive file is located and deserialized.
3. The original files are written back to their parent directories.
4. The __brarchive folder is removed and the tree is re-zipped.

Binary Format

Offset  Size  Field
0       8     Magic (0x267052A0B125277D, little-endian)
8       4     Entry count
12      4     Version (currently 1)

Per entry (repeated):
0       1     Name length (n)
1       247   Name (UTF-8, zero-padded)
248     4     Content offset (relative to content section)
252     4     Content length

Content section:
Concatenated file contents in descriptor order.

Project Structure

lib/
  core/
    brarchive/        Binary codec and zip/mcpack converter
    file_picker/      Native method-channel file picker
    i18n/             JSON-backed localization
    settings/         Persisted preferences
    theme/            Material 3 theme definitions
  ui/
    screens/          Home screen
  app_state.dart      Root state (i18n + theme)
  main.dart           Entry point
assets/
  i18n/               en.json, zh.json

Development

# Run unit tests
flutter test

# Static analysis
flutter analyze

# Run in debug mode
flutter run

Related Projects

• brarchive-go - The reference CLI implementation in Go.

License

This project is licensed under the Apache License, Version 2.0 - see the LICENSE file for details.