Communicate from ChildFragment to Parent when parent button's onClick

Question

I have a parent Fragment that has inside a FragementContainerView in which there is a transition of different Fragments. The parentFragment has a button that when is clicked it has to collect all the data from the different children fragments inside the container view. I am using Navigation component and FragmentResultAPI, the first for the fragment navigation/transition and the last for getting the results from the children to the parent. I know how to return back the data from the children to the parent, but I do not know how to notify the children to send the data back. I've found this:

View view = inflater.inflate(R.layout.parent_fragment, container, false);
MyFirstChildFragment fragment = (MyFirstChildFragment) getChildFragmentManager().findFragmentById(R.id.child_fragment_id);
fragment.heyChildrenGiveMeYourDataBack(); //on Button click listener

I know this is the traditional way, but I was wondering there was a more modern way or, let's call it, a Navigation way.

The parent fragment belongs to the main_graph_nav but all children belong to a different nested_graph_nav. So I have a scoped ViewModel to share the data between the children but still no idea how to notice the children to send the data back to the parent.

Convertible

Consider using an event bus. greenrobot.org/eventbus – Binnie

Answer 1

I finally decided to search the FragmentManager of the parent in the child's code in order to set the Fragment result by calling:

getParentFragment().getParentFragmentManager().setFragmentResult...

and inside the parent's code get the result by:

getChildFragmentManager().setFragmentResultListener...

Convertible

also have a look at my questions #70721718 and #70680827 – Hillary

your solutions works as there is another NavHost Fragment between parent and childFragment – Hillary