Why a fragment from the backstack gets triggered when adding a new fragment

Question

Something strange is happening..!

So I have an activity with TextView in the center of the toolbar acting as toolbar title, once the activity gets launched, I commit the MainFragment or let's name it Fragment (A).

• Inside Fragment (A), I replace it with Fragment (B) when a button gets clicked.
• Inside Fragment (B), I replace it with Fragment (C) when a button gets clicked.

so in each fragment I access the activity's toolbar text view and change it accordingly using this:

TextView title = getActivity().findViewById(R.id.titleText);
  title.setText("Some title");

And it works fine in Fragments (A) & (B), but in (C) it shows the title of Fragment (A)?? I even printed a log inside the onCreateView of each fragment and this is what showed up..!

the last two logs showed at the same time..!?

I/MY_TEST: onCreateView: of Fragment (A) I/MY_TEST: onCreateView: of Fragment (B) I/MY_TEST: onCreateView: of Fragment (C) I/MY_TEST: onCreateView: of Fragment (A)

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Update

Here's the full click listener

orderDetailsButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                AppCompatActivity activity = (AppCompatActivity) getActivity();
                Fragment fragment = new Teacher_Bar_Fragment();
                Bundle bundle = new Bundle();
                bundle.putInt("index", 1); // I use this to show or hide views
                fragment.setArguments(bundle);
                FragmentTransaction ft = activity.getSupportFragmentManager().beginTransaction();
                ft.replace(R.id.fragment_container, fragment);
                ft.addToBackStack(null);
                ft.commit();
            }
        });