Version

Tell us which versions you are using ( you can see the versions in your package.json ):

react-native-audio : 4.3.0
gradle-wrapper: 4.10.1
gradle: 3.3.0

Expected behaviour :

./gradlew app:build correctly builds the Android native code.

Actual behaviour

FAILURE: Build failed with an exception.

* What went wrong:
Could not resolve all files for configuration ':react-native-audio:debugCompileClasspath'.
> Could not find com.android.support:appcompat-v7:${supportVersion}.
  Required by:
      project :react-native-audio

The culprit here seems to be the usage of single quotes in build.gradle, which will not substitute the variable ${supportVersion}. After converting the quotes to double quotes, the library compiles.