Android pass value from child fragment back to parent fragment

Question

I was having some problem when trying to get the value from fragment upon dismiss. My fragment A will open up fragment B, when the button in fragment B is clicked, I wanted to get a value and pass back to fragment A to be displayed. However, I am not sure how to do it.

Fragment A:

@Click(R.id.buttonAttach)
void buttonAttachClicked(View v){
        SupportAttachFileFragment fragment = new SupportAttachFileFragment_();
        fragment.show(getFragmentManager(), null);

        // get value here and display
        textViewLogCounter.setText();
    }
}

Fragment B:

When this button onClicked, I wanted to pass the value back to fragment A and display.

@Click(R.id.buttonAttach)
void buttonAttachClicked(View v){
    System.out.println("TOTAL " + selectedRows.size());
    dismiss();
}

I not sure how to do it. I was thinking of Bundle but Bundle is to pass parameter to a new activity. In this case, my fragment is already opened but I wanted to pass some values back.

Any ideas? Thanks!

Answer 1

You can use shared ViewModel. Create ViewModel in activity scope and it will be available for activity and all of its fragment.

MyViewModel sharedViewModel = ViewModelProviders.of(getActivity()).get(MyViewModel::class.java)

Then observe your desire data of sharedViewModel. If you change data of sharedViewModel in any fragment or activity it will be changed for all fragment and activity. See below image or read doc.