How to use fragment method in Main Activity class

Create interface

public interface ListenFromActivity {    void doSomethingInFragment();}

In Activity class keep refrence of ListenFromActivity interface

public ListenFromActivity activityListener;   

Make public method to set listener

public void setActivityListener(ListenFromActivity activityListener) {        this.activityListener = activityListener;    }

Add some trigger point in activity class, here I have used user interaction

   @Override    public void onUserInteraction() {        super.onUserInteraction();

        if (null != activityListener) {            activityListener.doSomethingInFragment();        }    }

Now in Fragment class

make your fragment implement interface class

public class SomeFragment extends Fragment implements ListenFromActivity

Android studio will prompt you to implement method of interface in fragment

void doSomethingInFragment(){//Add your code here }

Final part part listener instance to activity like this in fragment onCreate method

((ListnerActivity) getActivity()).setActivityListener(SomeFragment.this);

DONE!!. now you can call fragment method from activity.