grpc/java/android

gRPC Hello World Tutorial (Android Java)

BACKGROUND

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

PREREQUISITES

• 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.

INSTALL

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

• Clone this git repo

$ 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

$ cp grpc-java/core/build/libs/*.jar your_app_dir/app/libs/
$ cp grpc-java/stub/build/libs/*.jar your_app_dir/app/libs/
$ cp grpc-java/nano/build/libs/*.jar your_app_dir/app/libs/
$ cp grpc-java/okhttp/build/libs/*.jar your_app_dir/app/libs/

• Copy or download other dependencies to your_app_dir/app/libs/
  • Guava 18
  • okhttp 2.2.0
  • okio
  • jsr305
  • protobuf nano:

$ cp ~/.m2/repository/com/google/protobuf/nano/protobuf-javanano/3.0.0-alpha-2/protobuf-javanano-3.0.0-alpha-2.jar your_app_dir/app/libs/

• Make sure your_app_dir/app/build.gradle contains:

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

6 Run your Helloworld Example app