MainActivity.java .... 4.2.2

import java.util.ArrayList;
import android.widget.EditText;
import android.widget.ListView;
import .... whatever

public class newItemFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
return inflater.inflate(R.layout.new_item_fragment, container, false);
}
}
----------------- page 129
Error code says: The public type newItemFragment must be defined in its own file. What does this involve?

Well the error description is pretty clear, you need to define NewItemFragment in a new file if it is not, just like the main activity.
I downloaded the code from this website and ran it, so I can attest that there is no error in this specific chapter. I suggest looking at the code itself and also the instruction they gave e.g. if it should replace a block of code or if it should be in a new file...

Thanks for responding, A23G.