Build an Android chat app with Llama, ExecuTorch, and XNNPACK
Introduction
Create a development environment
ExecuTorch Setup
Understanding Llama models
Prepare Llama models for ExecuTorch
Run Benchmark on Android phone
Build and Run Android chat app
Review
Next Steps

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Set up your development environment

In this Learning Path, you will learn how to build and deploy a simple LLM-based chat app to an Android device using ExecuTorch and XNNPACK. You will learn how to build the ExecuTorch runtime for Llama models, build JNI libraries for the Android application, and use the libraries in the application.

The first step is to prepare a development environment with the required software:

  • Android Studio (latest version recommended).
  • Android NDK version 25.0.8775105.
  • Java 17 JDK.
  • Git.
  • Python 3.10.

The instructions assume macOS with Apple Silicon, an x86 Debian, or Ubuntu Linux machine with at least 16GB of RAM.

Install Android Studio and Android NDK

Follow these steps to install and configure Android Studio:

  1. Download and install the latest version of Android Studio .

  2. Start Android Studio and open the Settings dialog.

  3. Navigate to Languages & Frameworks -> Android SDK.

  4. In the SDK Platforms tab, check Android 14.0 ("UpsideDownCake").

Next, install the specific version of the Android NDK that you need by first installing the Android command line tools:

Linux:

    

        
        
            curl https://dl.google.com/android/repository/commandlinetools-linux-11076708_latest.zip -o commandlinetools.zip

macOS:

    

        
        
            curl https://dl.google.com/android/repository/commandlinetools-mac-11076708_latest.zip -o commandlinetools.zip

Unzip the Android command line tools:

    

        
        
            unzip commandlinetools.zip

Install the NDK in the directory that Android Studio installed the SDK. This is generally ~/Library/Android/sdk by default:

    

        
        
            export ANDROID_HOME="$(realpath ~/Library/Android/sdk)"
./cmdline-tools/bin/sdkmanager --sdk_root="${ANDROID_HOME}" --install "ndk;25.0.8775105"

Install Java 17 JDK

Open the Java SE 17 Archive Downloads page in your browser.

Select an appropriate download for your development machine operating system.

Downloads are available for macOS as well as Linux.

Install Git

For macOS use Homebrew :

    

        
        
            brew install git

For Linux, use the package manager for your distribution:

    

        
        
            sudo apt install git-all

Install Python 3.10

For macOS:

    

        
        
            brew install python@3.10

For Linux:

    

        
        
            sudo apt update
udo apt install software-properties-common -y
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt install Python3.10

You now have the required development tools installed.

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