Flutter Android Bionic Builder

Minimal wrapper project for building the Flutter engine, Android embedding artifacts, and a Termux-ready Android-bionic host toolchain bundle with the Android NDK.

This repo does not vendor the full Flutter engine checkout. build.sh bootstraps depot_tools, fetches the Flutter engine source on first run, applies the local compatibility patches, and then builds either the requested Android ABI or the Termux host bundle overlay.

What it builds

• libflutter.so
• flutter.jar
• ABI-specific Android jar such as arm64_v8a_debug.jar
• a Termux host bundle tarball that overlays Flutter's bin/cache with:
  • Android-bionic dart-sdk
  • font-subset
  • const_finder.dart.snapshot
  • gen_snapshot for:
    • android-arm-profile/android-arm64
    • android-arm-release/android-arm64
    • android-arm64-profile/android-arm64
    • android-arm64-release/android-arm64
    • android-x64-profile/android-arm64
    • android-x64-release/android-arm64
• standalone mirror zips in dist/:
  • android-arm-profile-android-arm64.zip
  • android-arm-release-android-arm64.zip
  • android-arm64-profile-android-arm64.zip
  • android-arm64-release-android-arm64.zip
  • android-x64-profile-android-arm64.zip
  • android-x64-release-android-arm64.zip
  • dart-sdk-android-arm64.zip
  • dart-sdk-android-arm64-<engine-stamp>.zip
  • flutter_patched_sdk-<engine-stamp>.zip
  • flutter_patched_sdk_product-<engine-stamp>.zip
  • linux-arm64-tools-<engine-stamp>.zip

The Termux host bundle rewrites the Dart SDK version from prerelease syntax to stable build-metadata syntax (for example 3.7.0-260.0.dev becomes 3.7.0+260.0.dev) so Flutter's pub dependency resolution accepts it.

The current patch set is tuned for Android NDK r27c and keeps libflutter.so linked only against Android system libraries for broad compatibility.

Supported ABIs

• arm64-v8a
• armeabi-v7a
• x86
• x86_64

Prerequisites

• git
• python3
• Android NDK (ANDROID_NDK_HOME is preferred)

The script auto-detects these NDK locations:

• $ANDROID_NDK_HOME
• /root/codex-termux/.build-tools/android/android-ndk-r27c
• Flutter's vendored NDK inside the fetched checkout
• /data/data/com.termux/files/home/.build-tools/android/android-ndk-r27c

If curl or wget is unavailable, the script falls back to python3 for downloads.

Usage

Build one ABI:

./build.sh debug arm64-v8a y

Build all Android ABIs:

./build.sh debug all y

Build the Termux host bundle overlay:

./build.sh termux-sdk

Argument format:

./build.sh <debug|profile|release> <arm64-v8a|armeabi-v7a|x86|x86_64|all> <y|n>

The last flag controls whether Vulkan validation layers are disabled in debug builds for better portability.

The Termux host bundle command currently builds the arm64 host overlay only and writes a tarball into dist/.

Set FLUTTER_TERMUX_ENGINE_STAMP to override the engine-stamp suffix used for mirror zip names (default is Flutter 3.32.8 engine stamp: ef0cd000916d64fa0c5d09cc809fa7ad244a5767).

Patches

Stored patches live in patches/ and are applied automatically to the matching engine checkout (src/ or src/flutter/) when needed.

Contact

• GitHub: @sirvkrm
• Telegram: @sirvkrm (https://t.me/sirvkrm)