📱 Build Android Apps Natively in Termux: apkgen-cli, Gradle & Flutter

You do not need a PC, Android Studio or a cloud build service to make an Android APK anymore. With TermuxVoid, you can install the Android SDK, NDK and CMake directly on your phone, scaffold a project with apkgen-cli, and build both debug and release APKs natively in Termux.

This guide is for beginners. It covers Java, Kotlin, Native C/C++ and Flutter projects, plus how to sign a release APK and install it on your device.

What you need

• Termux installed from F-Droid or GitHub — not the Play Store build
• Android 7 or newer
• A few GB of free storage for the SDK, NDK and build caches
• Internet for the first install and for downloading Gradle dependencies
• aarch64 or x86_64 device (the Flutter package ships builds for these)

Step 1: Add the TermuxVoid repository

Use the setup that matches your Termux:

APT (dpkg):

curl -fsSL https://github.com/termuxvoid/repo/raw/main/install.sh | bash

Pacman:

curl -fsSL https://github.com/termuxvoid/pacman-repo/raw/main/install-repo.sh | bash

Then refresh the package lists:

pkg update

Piping a script to bash runs it immediately. If you prefer, download and read the installer first.

Step 2: Install the Android toolchain

pkg install android-sdk android-ndk android-cmake apkgen-cli

Here is what each package does:

$PREFIX is normally /data/data/com.termux/files/usr.

No environment variables are required. The apkgen templates already point Gradle at the TermuxVoid SDK, NDK and CMake paths.

Step 3: Meet apkgen-cli

apkgen-cli removes the repetitive Android setup. It can create a project and build it without you editing Gradle files by hand.

Open the interactive menu:

apkgen

Or use commands directly:

apkgen build debug and apkgen build release auto-detect the project type. Flutter projects get Flutter commands, everything else goes through Gradle.

Tip: Run apkgen help at any time to see the full command list.

Step 4: Build your first APK (Java)

Create a project:

apkgen create myapp

You will be asked for the app name and package name (for example com.example.myapp). Then enter the directory and build:

cd myapp
apkgen build debug

The debug APK is written to:

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

That file is already signed with the debug key, so it can be installed on a device right away.

Build a release APK

apkgen build release

Output:

app/build/outputs/apk/release/app-release-unsigned.apk

Gradle projects produce an unsigned release APK. You must sign it before installing or sharing it. The next step shows how.

Kotlin, C and C++

The workflow is identical, only the template changes:

apkgen create mykotlin --kotlin
apkgen create mynativec --nativec
apkgen create mynativecpp --nativecpp

Build any of them with apkgen build debug or apkgen build release. Native projects automatically use the installed NDK and CMake.

Step 5: Sign a release APK

Create a signing key once, then reuse it for every future release. Back it up — losing it means you cannot update your app with the same identity.

keytool -genkey -v -keystore my-release-key.jks -keyalg RSA \
  -keysize 2048 -validity 10000 -alias mykey

If keytool is missing, install a JDK:

pkg install openjdk-17

Align and sign the APK:

cd myapp

$PREFIX/opt/android-sdk/build-tools/37.0.0/zipalign -v 4 \
  app/build/outputs/apk/release/app-release-unsigned.apk \
  app-release-aligned.apk

$PREFIX/opt/android-sdk/build-tools/37.0.0/apksigner sign \
  --ks my-release-key.jks --out app-release-signed.apk \
  app-release-aligned.apk

Verify the signature:

$PREFIX/opt/android-sdk/build-tools/37.0.0/apksigner verify \
  --print-certs app-release-signed.apk

If the installed build-tools version differs, adjust the 37.0.0 in the paths:

ls "$PREFIX/opt/android-sdk/build-tools"

Step 6: Flutter on Termux (patched, debug and release)

TermuxVoid ships a custom patched Flutter SDK built from upstream Flutter source with Termux compatibility patches for Dart, Skia and the engine. The current package is based on Flutter 3.50.0 and includes release AOT snapshotters for arm, arm64 and x64.

That means both debug and release Android builds work on-device. Profile mode is not packaged.

Install Flutter

pkg install x11-repo
pkg install flutter

Verify it:

flutter --version

Point Flutter at the Android SDK

flutter config --android-sdk "$PREFIX/opt/android-sdk"
flutter doctor -v

This is a one-time setting. Do not set ANDROID_HOME, ANDROID_SDK_ROOT or ANDROID_NDK_HOME — the TermuxVoid packages and project files handle the paths.

Create a Flutter project

The easiest route is the apkgen Flutter template, because it already contains the required Termux-specific local.properties, gradle.properties and app/build.gradle.kts values:

apkgen create myflutter --flutter
cd myflutter

Check that Flutter sees the SDK:

flutter doctor -v

Build debug and release

Debug, split per ABI:

apkgen build flutter
# or: flutter build apk --debug --split-per-abi

Release:

apkgen build flutter release
# or: flutter build apk --release

Outputs:

build/app/outputs/flutter-apk/
├── app-<abi>-debug.apk    # debug, one per ABI
└── app-release.apk        # release, universal

Warning: Flutter release APKs from the default template are signed with the debug key. That is fine for testing and sideloading, but configure your own signing key before publishing or distributing the app.

Flutter project versions

Flutter 3.50.0 generates projects using:

• Android Gradle Plugin 9.3.1
• Kotlin 2.4.20
• Gradle 9.5.0

The apkgen Flutter template currently pins Android Gradle Plugin 9.1.0, Kotlin 2.4.0 and Gradle 9.3.1. Both combinations work. If you port an older project, align it with one of these sets.

Using flutter create instead

You can still use the normal Flutter command:

flutter create myapp
cd myapp

Then add the Termux paths and overrides yourself. The required edits are:

android/local.properties — absolute paths, no shell variables:

sdk.dir=/data/data/com.termux/files/usr/opt/android-sdk
flutter.sdk=/data/data/com.termux/files/usr/opt/flutter
cmake.dir=/data/data/com.termux/files/usr/opt/android-cmake/4.1.2
ndk.dir=/data/data/com.termux/files/usr/opt/android-ndk

android/gradle.properties — use the TermuxVoid aapt2:

android.aapt2FromMavenOverride=/data/data/com.termux/files/usr/opt/android-sdk/build-tools/37.0.0/aapt2

android/app/build.gradle.kts — match the installed build tools and NDK:

android {
    compileSdk = flutter.compileSdkVersion
    buildToolsVersion = "37.0.0"
    ndkVersion = "30.0.16248370"
    // ...
}

Full details: Building Android apps on Termux.

Step 7: Install the APK on your device

The Android SDK includes adb under platform-tools. Connect a device with USB debugging (or Android 11+ wireless debugging), then:

$PREFIX/opt/android-sdk/platform-tools/adb devices
$PREFIX/opt/android-sdk/platform-tools/adb install app-debug.apk

Use -r to replace an existing installation:

$PREFIX/opt/android-sdk/platform-tools/adb install -r app-release-signed.apk

No second device? Copy the APK to your Downloads folder, tap it in a file manager, and allow “Install unknown apps” for that file manager.

Troubleshooting

apkgen: command not found

The TermuxVoid repository is not configured or apkgen-cli is not installed:

pkg update
pkg install apkgen-cli

aapt2 not found or fails to run

Check the path in android/gradle.properties against the installed build-tools:

ls -l "$PREFIX/opt/android-sdk/build-tools/37.0.0/aapt2"

Update the path if the version number changed.

NDK version mismatch

Gradle must find the exact NDK version named in android/app/build.gradle.kts:

grep Pkg.Revision "$PREFIX/opt/android-ndk/source.properties"

Make both ndk.dir and ndkVersion match that value.

CMake not found

ls "$PREFIX/opt/android-cmake/4.1.2/bin/cmake"

Update cmake.dir if the installed version differs.

Gradle cannot find the Android SDK

flutter config --list | grep android-sdk
cat android/local.properties

Both paths must exist and point at the same SDK directory.

Flutter command not found or package missing

Re-add the TermuxVoid repository, run pkg update, then pkg install flutter again. Open a new shell if $PATH was cached.

Build killed or running out of memory

The templates set a large Gradle heap (-Xmx8G). On a low-RAM phone, lower it in android/gradle.properties:

org.gradle.jvmargs=-Xmx2G -XX:MaxMetaspaceSize=1G

Flutter license errors in flutter doctor

Accept the Android licenses once:

flutter doctor --android-licenses

Quick command cheat sheet

# Setup
pkg install android-sdk android-ndk android-cmake apkgen-cli
pkg install x11-repo flutter
flutter config --android-sdk "$PREFIX/opt/android-sdk"

# Java / Kotlin / C / C++
apkgen create myapp --kotlin
cd myapp
apkgen build debug
apkgen build release

# Flutter
apkgen create myflutter --flutter
cd myflutter
apkgen build flutter          # debug
apkgen build flutter release  # release

# Clean
apkgen clean

Links

• apkgen-cli
• Flutter for Termux
• Building Android apps on Termux
• TermuxVoid repository
• Pacman repository
• TermuxVoid website
• Telegram

Building APKs on a phone is slower than on a PC, but for learning, testing and small projects it works. Start with a debug build, then sign a release when you are ready to share your app.