Error importing library to android studio

Hi there,

I want to edit Smack 4.1 library & add custom tags to message class. I have done this in asmack. I am new to android studio. I have tried importing this library as a submodule to my project but its showing following error

Error:(12, 0) Could not find property ‘androidProjects’ on org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler_Dec orated@4e102b97.

Any idea about this error or how do I import this project as a submodule to edit it.