Context Crashes the App on library call

[JackIrongate]

I am trying the sample on my android app
I try using this

        AppChecker appChecker = new AppChecker();
        String packageName = appChecker.getForegroundApp(ctx);

I tried making a context ctx
Not sure which way I am suppose to call it for it to work with your library.

so far I tried
Context ctx = getApplicationContext();
and
Context ctx = getBaseContext();

Both of them crash the app when it runs the sample code.

I downloaded the library from the download link on github project
I added the .aar library to my project
fgchecker-1.0.1.aar
I added the dependency to my project
and I import
import com.rvalerio.fgchecker.AppChecker;