examples: Add an grpc-android dep to helloworld to demonstrate

Author: jdcormie

examples/MODULE.bazel

@@ -2,6 +2,8 @@ bazel_dep(name = "grpc-java", version = "1.82.0-SNAPSHOT", repo_name = "io_grpc_
 bazel_dep(name = "rules_java", version = "9.3.0")
 bazel_dep(name = "grpc-proto", version = "0.0.0-20240627-ec30f58", repo_name = "io_grpc_grpc_proto")
 bazel_dep(name = "protobuf", version = "33.1", repo_name = "com_google_protobuf")
+bazel_dep(name = "rules_android", version = "0.6.0")
+bazel_dep(name = "rules_proto", version = "7.1.0")
 bazel_dep(name = "rules_jvm_external", version = "6.0")
 
 # Do not use this override in your own MODULE.bazel. It is unnecessary when
@@ -26,7 +28,11 @@ maven.install(
     artifacts = [
         "com.google.api.grpc:grpc-google-cloud-pubsub-v1:0.1.24",
         "com.google.api.grpc:proto-google-cloud-pubsub-v1:0.1.24",
+        "androidx.appcompat:appcompat:1.0.0",
+    ],
+    repositories = [
+        "https://repo.maven.apache.org/maven2/",
+        "https://maven.google.com",
     ],
-    repositories = ["https://repo.maven.apache.org/maven2/"],
     strict_visibility = True,
 )

examples/android/helloworld/app/BUILD.bazel

@@ -0,0 +1,42 @@
+load("@rules_android//rules:rules.bzl", "android_binary")
+load("@io_grpc_grpc_java//:java_grpc_library.bzl", "java_grpc_library")
+load("@rules_proto//proto:defs.bzl", "proto_library")
+load("@rules_java//java:defs.bzl", "java_lite_proto_library")
+
+proto_library(
+    name = "helloworld_proto",
+    srcs = ["src/main/proto/helloworld.proto"],
+)
+
+java_lite_proto_library(
+    name = "helloworld_java_proto_lite",
+    deps = [":helloworld_proto"],
+)
+
+java_grpc_library(
+    name = "helloworld_java_grpc_lite",
+    srcs = [":helloworld_proto"],
+    flavor = "lite",
+    deps = [":helloworld_java_proto_lite"],
+)
+
+android_binary(
+    name = "app",
+    srcs = glob([
+        "src/main/java/**/*.java",
+    ]),
+    custom_package = "io.grpc.helloworldexample",
+    manifest = "src/main/AndroidManifest.xml",
+    resource_files = glob(["src/main/res/**"]),
+    visibility = ["//visibility:public"],
+    deps = [
+        ":helloworld_java_grpc_lite",
+        ":helloworld_java_proto_lite",
+        "@io_grpc_grpc_java//api",
+        "@io_grpc_grpc_java//android",
+        "@io_grpc_grpc_java//okhttp",
+        "@io_grpc_grpc_java//protobuf-lite",
+        "@io_grpc_grpc_java//stub",
+        "@maven//:androidx_appcompat_appcompat",
+    ],
+)

examples/android/helloworld/app/build.gradle

@@ -55,4 +55,5 @@ dependencies {
     implementation 'io.grpc:grpc-okhttp:1.82.0-SNAPSHOT' // CURRENT_GRPC_VERSION
     implementation 'io.grpc:grpc-protobuf-lite:1.82.0-SNAPSHOT' // CURRENT_GRPC_VERSION
     implementation 'io.grpc:grpc-stub:1.82.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+    implementation 'io.grpc:grpc-android:1.82.0-SNAPSHOT' // CURRENT_GRPC_VERSION
 }

examples/android/helloworld/app/src/main/java/io/grpc/helloworldexample/HelloworldActivity.java

@@ -29,7 +29,7 @@
 import android.widget.EditText;
 import android.widget.TextView;
 import io.grpc.ManagedChannel;
-import io.grpc.ManagedChannelBuilder;
+import io.grpc.android.AndroidChannelBuilder;
 import io.grpc.examples.helloworld.GreeterGrpc;
 import io.grpc.examples.helloworld.HelloReply;
 import io.grpc.examples.helloworld.HelloRequest;
@@ -91,7 +91,12 @@ protected String doInBackground(String... params) {
       String portStr = params[2];
       int port = TextUtils.isEmpty(portStr) ? 0 : Integer.valueOf(portStr);
       try {
-        channel = ManagedChannelBuilder.forAddress(host, port).usePlaintext().build();
+        Activity activity = activityReference.get();
+        AndroidChannelBuilder channelBuilder = AndroidChannelBuilder.forAddress(host, port);
+        if (activity != null) {
+          channelBuilder.context(activity.getApplicationContext());
+        }
+        channel = channelBuilder.usePlaintext().build();
         GreeterGrpc.GreeterBlockingStub stub = GreeterGrpc.newBlockingStub(channel);
         HelloRequest request = HelloRequest.newBuilder().setName(message).build();
         HelloReply reply = stub.sayHello(request);