Move data from Fragment to Activity in the back

I have a ViewPager in my Activity. I need to return the result from the fragments in the ViewPager to the activity. At the same time, the returned data will be added to the list in the activity. So I think the example of activity should not disappear. I don't know if I do it with Bundle. Would it be a good solution to move a singleton with object? What's the best practice for this, friends?

Thank you very much for your reply. I guess I may not have written my question clearly. In fact, the ViewPager in a CameraActivity has CameraFragment and GalleryFragment. This means that more than one activity can call CameraActivity. CameraFragment or GalleryFragment should be able to return the captured or selected photo to Activity / Fragmet, which calls CameraActivity of the "File" type.

add an interface to your fragment and pass your data with that.

class FragmentCategory : Fragment() {
 private lateinit var delegate: Interaction

 interface Interaction {
        fun onSelect(testParam:String)
        fun onShowLoading()
        fun onHideLoading()
    }

 companion object {
        fun newInstance(delegate: Interaction): FragmentCategory {
            val frag = FragmentCategory()
            val args = Bundle()
            frag.arguments = args
            frag.delegate = delegate
            return frag
        }

    }


    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val view: View = inflater.inflate(
            R.layout.fragment_category_main,
            container, false
        )

         //for example you can use delegate.onSelect("test") for pass data to your activity 
         return view
    }
}

using that fragment:

val frgCategory= FragmentCategory.newInstance(object : FragmentCategory.Interaction {
            override fun onSelect(testParam:String) {
               
            }

            override fun onShowLoading() {
               
            }

            override fun onHideLoading() {
               
            }

        })

Here's what you can do (assuming you want to pass back long value):

Define an interface that will be used to communicate between ViewPager's fragments and the activity

public interface CommunicationInterface {
    public void onDataReady(long value);
}

Let your activity implement such interface.

public class MainActivity extends AppCompatActivity implements CommunicationInterface {
    @Override
    public void onDataReady(long value) {
        // data received from the fragments.
        // here you can put the value into the list and display it
    }
}

On the fragments, make sure to get the parent activity reference by getting it on the onActivityCreated callback:

public class FragmentTest extends Fragment {

    private CommunicationInterface parentActivity;

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        parentActivity = (CommunicationInterface) getActivity();
    }
}

Now, when you want to communicate back to the activity, just use

parentActivity.onDataReady(3L);

making sure that parentActivity is not called after onActivityCreated callback (just check that is not null).

Hope this helps.