android/app/build.gradle
ここを忘れないよう。
defaultConfig { // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html). applicationId "com.shinriyo.cafemaster" minSdkVersion 16 targetSdkVersion 27 versionCode 2 versionName "1.1" testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"