使用导航架构组件启动带有结果的片段

Question

Below is how i am navigating from fragment A to fragment B using android navigation

    @Override
    public void onClick(View view) {

        int viewId = view.getId();

        if (viewId == R.id.btn_proceed) {
          
          Navigation.findNavController(view).navigate(R.id.fragmentB);

        }
    }

I would like to achieve returning of results from fragmentB to fragmentA where for example fragmentB has an EditText that a user keys in text and is returned to fragmentA and set to TextView using android architecture navigation components

Answer 1

According to documentation on returning a result i was able to achieve what i was asking with the code below.

Declare a NavController

private NavController navController;

Inside onViewCreated method

navController = Navigation.findNavController(view);

        MutableLiveData<String> liveData = Objects.requireNonNull(navController.getCurrentBackStackEntry())
                .getSavedStateHandle()
                .getLiveData("key");

To get result in FragmentA from FragmentB

 liveData.observe(getViewLifecycleOwner(), s -> {

           tvResult.setText(s);

        });

In FragmentB do the following, for example when a button is clicked

@Override
    public void onClick(View view) {

        int viewId = view.getId();

        NavController navController = Navigation.findNavController(view);

        if (viewId == R.id.btn_returnResult) {

            String etText = editText.getText().toString();

            Objects.requireNonNull(navController.getPreviousBackStackEntry())
                    .getSavedStateHandle().set("key", etText);

            navController.navigateUp();

        }
    }