class BasicFragment : Fragment() {
private var listener: LoopFragment.OnFragmentInteractionListener? = null

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                          savedInstanceState: Bundle?): View? {
    val view = inflater.inflate(R.layout.fragment_basic, container, false)
    val button1 = view.findViewById<Button>(R.id.button1)
    button1.setOnClickListener {
        onButtonPressed("Basic Fragment")
    }
    return view
}

override fun onAttach(context: Context) {
    super.onAttach(context)
    if (context is OnFragmentInteractionListener) {
        listener = context
    } else {
        throw RuntimeException(context.toString() + " must implement OnFragmentInteractionListener")
    }
}

override fun onDetach() {
    super.onDetach()
    listener = null
}


fun onButtonPressed(str: String) {
    listener?.onFragmentInteraction(str)
}

interface OnFragmentInteractionListener {
    fun onFragmentInteraction(str: String)
}}