Pass data from Bottom Sheet Dialog Fragment to Fragment

Question

I am using a BottomSheetDialogFragment class with Navigation Architecture component. I am following the Single activity pattern and therefore i have only one activity and several fragments. Below is my code.

BottomSheetDialogFragment.kt

class LogoBottomSheetFragment : BottomSheetDialogFragment() {

private var _binding: FragmentBottomSheetAccountLogoBinding? = null
private val binding get() = _binding!!

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    _binding = FragmentBottomSheetAccountLogoBinding.inflate(inflater, container, false)

    return binding.root
}

override fun onDestroyView() {
    super.onDestroyView()
    _binding = null
}
}

And this is how i open the dialog in my navigation.xml from my main fragment:

    <dialog
    android:id="@+id/logoBottomSheetFragment"
    android:name="com.th3pl4gu3.locky.ui.main.add.account.LogoBottomSheetFragment"
    android:label="LogoBottomSheetFragment"
    tools:layout="@layout/fragment_bottom_sheet_account_logo" />

Now i want to pass data FROM the bottom sheet to the main fragment.

Is there a proper way to do this? Can someone please help me.

Thank you.

Answer 1

As of Navigation 2.3.0-alpha02 , Navigation has built in support for Returning a result to a previous destination.

This works in two parts, your first fragment (the one wanting to receive the result) would use navController.currentBackStackEntry?.savedStateHandle to get a reference to the SavedStateHandle associated with its NavBackStackEntry in the NavController. Then, it can observe a particular key to get a callback whenever that key changes.

The second fragment (the one delivering the result, ie, your LogoBottomSheetFragment ) would get a reference to that exact same SavedStateHandle by using navController.previousBackStackEntry?.savedStateHandle . When that second fragment calls set on the SavedStateHandle , that result is then made available for the first fragment.

Note that there are some DialogFragment specific considerations to keep in mind - because the previous fragment is RESUMED even when the BottomSheetFragment is being shown, the result will instantly be sent to your first fragment.