From 5cc4decbcf72dd3728c803a2dd515b62a15a7006 Mon Sep 17 00:00:00 2001
From: andriy <andriy@debian.lan>
Date: Tue, 19 Mar 2024 14:06:40 +0100
Subject: [PATCH] initial commit

---
 .gitignore         |  2 ++
 README.md          | 86 ++++++++++++++++++++++++++++++++++++++++++++++
 compile.sh         | 10 ++++++
 run.sh             | 16 +++++++++
 src/CMakeLists.txt |  7 ++++
 src/main.cpp       |  7 ++++
 6 files changed, 128 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 README.md
 create mode 100755 compile.sh
 create mode 100755 run.sh
 create mode 100644 src/CMakeLists.txt
 create mode 100644 src/main.cpp

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5e69491
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+build/
+.obsidian/
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..d650487
--- /dev/null
+++ b/README.md
@@ -0,0 +1,86 @@
+This project is a simple demo of how to compile&run native **Aarch64** (or **x86**) binary on a Android device. 
+
+# TL;DR
+
+*.bashrc*
+```bash
+export ANDROID_NDK="~/bin/android-ndk/r26c-linux"
+export ANDROID_SDK_ROOT="~/bin/android_sdk_root"
+export PATH="$PATH:$ANDROID_SDK_ROOT/cmdline-tools/latest/bin:$ANDROID_SDK_ROOT/emulator:$ANDROID_SDK_ROOT/platform-tools"
+```
+
+# Compile with Android NDK 
+
+- [Download](https://developer.android.com/ndk/downloads) latest version of Android NDK. I'm going go use Linux distribution.
+- Set `ANDROID_NDK` Environment Variable to the extracted contents of an archive.
+- At this point you should be able to compile the project with `compile.sh` script.
+
+# Run
+
+Technically, if you have Android device with `Development Mode ON` and `adb` binary somewhere on your host PC - you shall be able to install and execute compiled artifact from previous step with help of `run.sh` script. If that is not what you want or have - next sections are for you. 
+
+# Android Emulator without Android Studio
+
+**Directory Structure**
+```
+$ANDROID_SDK_ROOT/
+├── cmdline-tools/
+|   └── latest/
+|       └── bin/
+|           ├── avdmanager
+|           ├── sdkmanager
+|           ├── ...
+|── emulator/
+|── platforms/
+|   └─ android-23/
+|── platform-tools/
+|   ├─ adb
+|   ├─ fastboot
+|   ├─ ...
+|── system-images/
+|   └─ android-23/
+```
+
+## cmdline-tools
+
+- [Download](https://developer.android.com/studio#command-tools) Command line tools only.
+- Set  `ANDROID_SDK_ROOT` Environment Variable to the extracted contents of downloaded archive. It is recommended to follow next convention:
+  `$ANDROID_SDK_ROOT/cmdline-tools/latest/bin`
+- Add it to `PATH`. 
+  
+## sdkmanager
+
+- List available packages with:
+```bash
+sdkmanager --list
+```
+
+> [!NOTE] QEMU host limitations
+> It looks that Android API 27 is the latest officially supported OS image that is capable of being executed as **Aarch64** Android on **x86_64** host. Later versions of Android can be used only as **x86_64** binaries.
+
+- Install packages for Android API 27 (MARSHMELLOW (6.0), etc) 
+```bash
+sdkmanager "system-images;android-27;default;arm64-v8a" "platforms;android-27"
+```
+  
+## emulator
+
+- Install emulator and tools: 
+```bash
+sdkmanager "emulator" "platform-tools"
+```
+
+- Add tools to `PATH`: `$ANDROID_SDK_ROOT/emulator`, `$ANDROID_SDK_ROOT/platform-tools`
+
+- Create emulator device: 
+```bash
+avdmanager --verbose create avd --force --name "pixel_6.0_27" --device "pixel" --package "system-images;android-27;default;arm64-v8a" --tag "default" --abi "arm64-v8a"
+``` 
+
+- Start emulator: 
+```bash
+emulator @pixel_6.27  -qemu -machine virt
+```
+
+> [!NOTE] -qemu -machine virt
+> This two options are only necessary if you are going to run **Aarch64** Android on a **x86_64** host.  
diff --git a/compile.sh b/compile.sh
new file mode 100755
index 0000000..a1c1896
--- /dev/null
+++ b/compile.sh
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -euxo pipefail
+
+cmake \
+	-DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake \
+	-DANDROID_ABI=arm64-v8a \
+	-Bbuild \
+	-Ssrc
+	
+cmake --build build/
diff --git a/run.sh b/run.sh
new file mode 100755
index 0000000..5a4aa25
--- /dev/null
+++ b/run.sh
@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -euxo pipefail
+
+#
+# Create emulator
+#
+# avdmanager --verbose create avd --force --name "pixel_6.0" --device "pixel" --package "system-images;android-23;google_apis;arm64-v8a" --tag "google_apis" --abi "arm64-v8a"
+
+
+#
+# Run emulator
+#
+# emulator @pixel_6.0
+
+adb push build/hello-android-cli /data/local/tmp
+adb shell /data/local/tmp/hello-android-cli
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
new file mode 100644
index 0000000..b270e5e
--- /dev/null
+++ b/src/CMakeLists.txt
@@ -0,0 +1,7 @@
+project(hello-android-cli)
+
+cmake_minimum_required(VERSION 3.16.0)
+
+add_executable(${PROJECT_NAME}
+	main.cpp
+	) 
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..8fc9676
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,7 @@
+#include <iostream>
+
+int main(int argc, char** argv)
+{
+    std::cout << "Hello Android CLI" << std::endl;
+    return 0;
+}