Handle activity backpressed from fragment.

fragment-backpressed-listener.kt

/**
 * Extension function for the fragment to handle the activity backPressed().
 * Call this inside [Fragment.onAttach] method.
 *
 * @param backPressed is invoked when the activity triggers onBackPressed().
 * @see [https://developer.android.com/reference/androidx/activity/OnBackPressedDispatcher]
 */
inline fun Fragment.handleActivityBackPressed(
    crossinline backPressed: () -> Unit
) {
    requireActivity().onBackPressedDispatcher.addCallback(
        this,
        object : OnBackPressedCallback(
            true // default to enabled
        ) {
            override fun handleOnBackPressed() {
                backPressed()
            }
        }
    )
}

// Usage ->

class MyFragment : Fragment(R.layout.fragment_my) {

    ...

    override fun onAttach(context: Context) {
        super.onAttach(context)
        handleActivityBackPressed {
            //Do something here.
        }
    }
}