Choose "Kotlin" as the development language and create a Blank Activity which gives you basic Project Setup. Among it, the below are the only required items in for the Home Activity
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
}
And adding a function is as easy like
this.callMe();
private fun callMe() {
// Function called
}
Pretty much javascript :p
And toast like this
import android.widget.Toast
Toast.makeText(this@YourActivity, "Hello there", Toast.LENGTH_SHORT).show();
That's it !