before(default)

implementation fileTree(include: ['*.jar'], dir: 'libs') 

just add '*.aar' in include array.

implementation fileTree(include: ['*.jar', '*.aar'], dir: 'libs') 

it works well on Android Studio 3.x.

before(default)

implementation fileTree(include: ['*.jar'], dir: 'libs') 

just add '*.aar' in include array.

implementation fileTree(include: ['*.jar', '*.aar'], dir: 'libs') 

it works well on Android Studio 3.x.

if you want ignore some library? do like this.

implementation fileTree(include: ['*.jar', '*.aar'], exclude: 'test_aar*', dir: 'libs') debugImplementation files('libs/test_aar-debug.aar') releaseImplementation files('libs/test_aar-release.aar') 

implementation fileTree(include: ['*.jar', '*.aar'], dir: 'libs') 

before(default)

implementation fileTree(include: ['*.jar'], dir: 'libs') 

just add '*.aar' in include array.

implementation fileTree(include: ['*.jar', '*.aar'], dir: 'libs') 

it works well on Android Studio 3.x.