When flipping the screen, two EditTexts appear, one overlaps the other, how to fix it?

Question

Java

I wrote a calculator, I used EditText for the number output field, the problem is that when I turn the screen, it looks like I have two EditTexts, as a result, the values ​​\u200b\u200bare added to one, and the other is default, and it interferes

Answer 1

The problem is most likely in how you show the fragment.
You need to check if the fragment is already added, if added, either replace or show

// показываем нужный фрагмент
    private void showFragment(Fragment fragment) {
        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction transaction = fm.beginTransaction();
        if (fm.findFragmentByTag(TAG) == null) {
            transaction.add(R.id.activity_content, fragment, TAG);
        } else if (fragment.getClass().equals(fm.findFragmentByTag(TAG).getClass())){
            transaction.show(fragment);
        } else {
            transaction.replace(R.id.activity_content, fragment, TAG);
        }
        //transaction.addToBackStack(fragment.getClass().getName());
        transaction.commit();
    }