Check if the content implements an interface

ExampleFragment.kt

import android.content.Context
import androidx.fragment.app.Fragment
import com.codingwithmitch.mviexample.ui.DataStateListener
import java.lang.ClassCastException


class ExampleFragment : Fragment() {

    lateinit var dataStateHandler: DataStateListener

    override fun onAttach(context: Context) {
        super.onAttach(context)
        try {
            dataStateHandler = context as DataStateListener
        }catch(e: ClassCastException) {
            println("DEBUG: $context must implement DataStateListener")
        }
    }
}