gRPC Hello World Tutorial (Android Java)

BACKGROUND

For this sample, we've already generated the server and client stubs from helloworld.proto.

Java gRPC
Android Tutorial If you're new to Android development
We only have Android gRPC client in this example. Please follow examples in other languages to build and run a gRPC server.

1 Clone the gRPC Java git repo

$ git clone https://github.com/grpc/grpc-java

2 Install gRPC Java, as described in How to Build

$ # from this dir
$ cd grpc-java
$ # follow the instructions in 'How to Build'

3 Create an Android project under your working directory.

Set Application name to "Helloworld Example" and set Company Domain to "grpc.io". Make sure your package name is "io.grpc.helloworldexample"
Choose appropriate minimum SDK
Use Blank Activity
Set Activity Name to HelloworldActivity
Set Layout Name to activity_helloworld

4 Prepare the app

$ git clone https://github.com/grpc/grpc-common

Replace the generated HelloworldActivity.java and activity_helloworld.xml with the two files in this repo
Copy GreeterGrpc.java and Helloworld.java under your_app_dir/app/src/main/java/io/grpc/examples/
In your AndroidManifest.xml, make sure you have

<uses-permission android:name="android.permission.INTERNET" />

added outside your appplication tag

5 Add dependencies. gRPC Java on Android depends on grpc-java, protobuf nano, okhttp

Copy grpc-java .jar files to your_app_dir/app/libs/:
- grpc-java/core/build/libs/*.jar
- grpc-java/stub/build/libs/*.jar
- grpc-java/nano/build/libs/*.jar
- grpc-java/okhttp/build/libs/*.jar
Copy or download other dependencies to your_app_dir/app/libs/:
- Guava 18
- okhttp 2.2.0
- protobuf nano:

$ cp ~/.m2/repository/com/google/protobuf/nano/protobuf-javanano/2.6.2-pre/protobuf-javanano-2.6.2-pre.jar your_app_dir/app/libs/

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
}