Cannot import com.google.cloud.speech.v1.SpeechGrpc in Android

If you add the proto directory on GoogleCloudPlatform/android-docs-samples to your android application source(app/src/main/), it will work fine even though you don't write [compile group: 'com.google.cloud', name: 'google-cloud-speech', version: '0.17.1-alpha'] on your build.gradle(Module:app).

Add the following dependency in your build.gradle.

implementation 'com.google.api.grpc:grpc-google-cloud-speech-v1:1.23.0';