Building Android

There are following Apps on Android

• CHIPTool - Android CHIPTool is an application for Android for commissioning and controlling Matter accessory devices. It offers the following features:
  • Scan a Matter QR code and display payload information to the user
  • Read the NFC tag containing Matter onboarding information
  • Commission a Matter device
  • Send echo requests to the Matter echo server
  • Send on/off cluster requests to a Matter device
• CHIPTest
  • Android CHIPTest is an application for Android for running Matter's unit tests

• Building Android
  • Source files
  • Requirements for building
    • Linux
    • MacOS
    • ABIs and TARGET_CPU
    • Gradle & JDK Version
  • Preparing for build
  • Building Android CHIPTool from scripts
  • Building Android CHIPTool from Android Studio
  • Building Android CHIPTest from scripts

Source files

You can find source files of the Android applications in the examples/android/ directory.

Requirements for building

You need Android SDK 21 & NDK 21.4.7075529 downloaded to your machine. Set the $ANDROID_HOME environment variable to where the SDK is downloaded and the $ANDROID_NDK_HOME environment variable to point to where the NDK package is downloaded.

1. Install Android Studio
2. Install NDK:
   1. Tools -> SDK Manager -> SDK Tools Tab
   2. Click [x] Show Package Details
   3. Select NDK (Side by Side) -> 21.4.7075529
   4. Apply
3. Install Command Line Tools:
   1. Tools -> SDK Manager -> SDK Tools Tab -> Android SDK Command Line Tools (latest)
   2. Apply
4. Install SDK 21:
   1. Tools -> SDK Manager -> SDK Platforms Tab -> Android 5.0 (Lollipop) SDK Level 21
   2. Apply
5. Install Emulator:
   1. Tools -> Device Manager -> Create device -> Pixel 5 -> Android S API 31 -> Download

Linux

export ANDROID_HOME=~/Android/Sdk
export ANDROID_NDK_HOME=~/Android/Sdk/ndk/21.4.7075529

MacOS

export ANDROID_HOME=~/Library/Android/sdk
export ANDROID_NDK_HOME=~/Library/Android/sdk/ndk/21.4.7075529

ABIs and TARGET_CPU

TARGET_CPU can have the following values, depending on your smartphone CPU architecture:

ABI	TARGET_CPU
armeabi-v7a	arm
arm64-v8a	arm64
x86	x86
x86_64	x64

Gradle & JDK Version

We are using Gradle 7.1.1 for all android project which does not support Java 17 (https://docs.gradle.org/current/userguide/compatibility.html) while the default JDK version on MacOS for Apple Silicon is ‘openjdk 17.0.1’ or above.

Using JDK bundled with Android Studio will help with that.

export JAVA_HOME=/Applications/Android\ Studio.app/Contents/jre/Contents/Home/

Preparing for build

Complete the following steps to prepare the Matter build:

1. Check out the Matter repository.

2. Run bootstrap (only required first time)

   source scripts/bootstrap.sh
   

3. Choose how you want to build the Android CHIPTool. There are two ways: from script, or from source within Android Studio.

Building Android CHIPTool from scripts

This is the simplest option. In the command line, run the following command from the top CHIP directory:

./scripts/build/build_examples.py --target android-arm64-chip-tool build

See the table above for other values of TARGET_CPU.

The debug Android package app-debug.apk will be generated at out/android-$TARGET_CPU-chip-tool/outputs/apk/debug/, and can be installed with

adb install out/android-$TARGET_CPU-chip-tool/outputs/apk/debug/app-debug.apk

You can use Android Studio to edit the Android CHIPTool app itself and run it after build_examples.py, but you will not be able to edit Matter Android code from src/controller/java, or other Matter C++ code within Android Studio.

Building Android CHIPTool from Android Studio

This option allows Android Studio to build the core Matter code from source, which allows us to directly edit core Matter code in-IDE.

1. In the command line, run the following command from the top Matter directory:

   TARGET_CPU=arm64 ./scripts/examples/android_app_ide.sh
   

   See the table above for other values of TARGET_CPU.

2. Modify the matterSdkSourceBuild variable to true, matterBuildSrcDir point to the appropriate output directory (e.g. ../../../../out/android_arm64), and matterSourceBuildAbiFilters to the desired ABIs in examples/android/CHIPTool/gradle.properties

3. Open the project in Android Studio and run File -> Sync Project with Gradle Files.

4. Use one of the following options to build an Android package:

   • Click Make Project in Android Studio.

   • Run the following command in the command line:

     cd examples/android/CHIPTool
     ./gradlew build
     

The debug Android package app-debug.apk will be generated at examples/android/CHIPTool/app/build/outputs/apk/debug/, and can be installed with

adb install examples/android/CHIPTool/app/build/outputs/apk/debug/app-debug.apk

or

(cd examples/android/CHIPTool && ./gradlew installDebug)

Building Android CHIPTest from scripts

Currently, the CHIPTest can only be built from scripts. The steps are similar to building CHIPTool from scripts.

./scripts/build/build_examples.py --target android-arm64-chip-test build

You can modify the matterUTestLib variable to the test lib in examples/android/CHIPTest/gradle.properties to change target to test.