Apk2kotlin

A native C tool that decompiles Android APK files and reconstructs clean, compilable Android Studio Gradle projects with target source code in either Kotlin (.kt) or Java (.java).

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Features

• Native C Implementation: Written in C for fast execution and lightweight overhead.
• Dual Target Language Support: Decompile and transpile APKs into Kotlin (.kt) or Java (.java) source trees.
• Automatic Package Extraction: Parses package names and components directly from the decompiled AndroidManifest.xml.
• Complete Gradle Project Structure: Generates settings.gradle.kts, build.gradle.kts, gradle.properties, app/build.gradle.kts, and app/src/main/AndroidManifest.xml.
• Resource Sanitization & Preservation: Extracts layouts, drawables, values, and XML resources while sanitizing invalid file names.
• Modular Design: Separated into single-function C modules with header declarations and a unified Makefile.
• Multiplatform: Support for android (arm64 & x86_64), windows (arm64 & x86_64) and GNU linux (arm64 & x86_64).
• One script: Just download the script for your os and execute it and it will do everything.

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Architecture & Module Overview

The codebase is organized under src/ into distinct modules:

Module File	Header	Description
src/apk_to_smali.c	src/apk_to_smali.h	Extracts resources, Smali code, and AndroidManifest.xml via apktool
src/dex_to_smali.c	src/dex_to_smali.h	Disassembles raw .dex bytecode files to .smali
src/smali_to_kotlin.c	src/smali_to_kotlin.h	Decompiles bytecode and handles Kotlin (.kt) or Java (.java) transpilation
src/manifest_parser.c	src/manifest_parser.h	Extracts package="..." attribute from decompiled XML manifests
src/gradle_generator.c	src/gradle_generator.h	Creates Kotlin DSL Gradle build scripts and properties
src/file_utils.c	src/file_utils.h	Manages file I/O, directory creation, recursive copying, and resource sanitization
src/main.c	N/A	Main CLI entrypoint parsing arguments and driving execution

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Prerequisites

Ensure the following dependencies are installed and available in system environment or binary paths:

• GCC (gcc) and Make (make)
• JDK 17 or higher (java)
• apktool (in system PATH)
• jadx (in system PATH)

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Building from Source

To compile the native C binary in your arch using the provided Makefile:

make clean && make <win-x86_64|win-arm64|linux-x86_64|linux-arm64|android-x86_64|android-arm64>

Or to build all:

make clean && make all

The compiled binaries will be placed at bin/apk2kotlin.

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Command-Line Usage

bin/apk2kotlin <input_apk> <output_project_dir> [kotlin|java]

Parameters

1. <input_apk>: Path to the target .apk file.
2. <output_project_dir>: Path where the generated Android Studio Gradle project will be created.
3. [kotlin|java] (Optional): Target programming language for source output.
   • kotlin (default): Places .kt source files in app/src/main/kotlin/.
   • java: Places .java source files in app/src/main/java/.

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Credits <3

• Jadx for the dex decompile tool
• Apktool for apk to smali
• Bard for debugging

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