gRPC-core BinderTransport example apps

Build Instruction

1. Install Android SDK and NDK. Only NDK version >= 25 is supported. We tested against SDK Platform 33 and NDK 26.2.11394342.
2. Make sure Bazel is at least 7.0. Use export OVERRIDE_BAZEL_VERSION=7.3.1 to selected a supported version listed in bazel/supported_versions.txt if necessary.
3. Point environment variables to install locations of SDK and NDK

   export ANDROID_HOME=$HOME/android-sdk
   export ANDROID_NDK_HOME=$HOME/android-sdk/ndk/26.2.11394342
   

4. To build a fat APK that supports x86_64, armv7, and arm64:

   bazel build \
     --extra_toolchains=@androidndk//:all \
     --android_platforms=//bazel/platforms/android:x86_64,//bazel/platforms/android:armeabi-v7a,//bazel/platforms/android:arm64-v8a \
     --copt=-Wno-unknown-warning-option \
     //examples/android/binder/java/io/grpc/binder/cpp/exampleserver:app \
     //examples/android/binder/java/io/grpc/binder/cpp/exampleclient:app
   

5. adb install bazel-bin/examples/android/binder/java/io/grpc/binder/cpp/exampleclient/app.apk
6. adb install bazel-bin/examples/android/binder/java/io/grpc/binder/cpp/exampleserver/app.apk