android - onClickListener がフラグメントで機能しない

Question

public class MainFragment extends Fragment {
    public static final String TAG = MainFragment.class.getSimpleName();
    private static final String ABOUT_SCHEME = "settings";
    private static final String ABOUT_AUTHORITY = "main";
    public static final Uri ABOUT_URI = new Uri.Builder().scheme(ABOUT_SCHEME).authority(ABOUT_AUTHORITY).build();

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

        View v = inflater.inflate(R.layout.mainbutton, container, false);

        return v;
    }

}

以下のリンクによると: How to handle button clicks using the XML onClick within Fragments

public class StartFragment extends Fragment implements OnClickListener{


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

        View v = inflater.inflate(R.layout.fragment_start, container, false);

        Button b = (Button) v.findViewById(R.id.StartButton);
        b.setOnClickListener(this);
        return v;
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.StartButton:

                /* ... */

                break;
        }
    }
}

ソースも機能しません。