# Matter TV Casting Android App Example

This is a Matter TV Casting Android app that can be used to cast content to a
TV. This app discovers TVs on the local network that act as commissioners, lets
the user select one, sends the TV a User Directed Commissioning request, enters
commissioning mode, advertises itself as a Commissionable Node and gets
commissioned. Then it allows the user to send Matter ContentLauncher commands to
the TV.

<hr>

-   [Matter TV Casting Android App Example](#matter-tv-casting-android-app-example)
    -   [Requirements for building](#requirements-for-building)
        -   [ABIs and TARGET_CPU](#abis-and-target_cpu)
        -   [Gradle \& JDK Version](#gradle--jdk-version)
    -   [Preparing for build](#preparing-for-build)
    -   [Building \& Installing the app](#building--installing-the-app)

<hr>

## Requirements for building

Refer to
[this file](../../../docs/platforms/android/android_building.md#requirements-for-building)
to download the recommended version for the Android SDK and NDK for 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.

```
export ANDROID_HOME=~/Library/Android/sdk
export ANDROID_NDK_HOME=~/Library/Android/sdk/ndk/{NDK_VERSION_NUMBER}
```

### 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.

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

<hr>

## 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**)

    ```shell
    source scripts/bootstrap.sh
    ```

3. The build will produce libraries: AndroidPlatform.jar, CHIPAppServer.jar,
   CHIPInteractionModel.jar and TVCastingApp.jar in [App/app/libs](App/app/libs)
   and libTvCastingApp.so and libc++\_shared.so in
   [App/app/libs/jniLibs/](App/app/libs/jniLibs/) consumed by any casting app to
   leverage the [casting APIs](../APIs.md), like the sample android
   tv-casting-app. If building for your own casting app, make sure your client's
   specific values are set for `CHIP_DEVICE_CONFIG_DEVICE_VENDOR_ID` and
   `CHIP_DEVICE_CONFIG_DEVICE_PRODUCT_ID` in the
   [CHIPProjectAppConfig.h](tv-casting-common/include/CHIPProjectAppConfig.h)
   file, before the build. Other values like the
   `CHIP_DEVICE_CONFIG_DEVICE_NAME` may be optionally updated as well.

## Building & Installing the app

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

```shell
./scripts/build/build_examples.py --target android-arm64-tv-casting-app build
```

(To build this app with no debugging hooks, use the
`android-arm64-tv-casting-app-no-debug` target)

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-tv-casting-app/outputs/apk/debug/`, and can be
installed with

```shell
adb install out/android-$TARGET_CPU-tv-casting-app/outputs/apk/debug/app-debug.apk
```

You can use Android Studio to edit the Android 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.