Why are my CheckBoxe's state never saved?

I have a few CheckBox elements inside one of my Fragments.

Every time I leave this Fragment it seems to nor save or restore the checked state of each one provided by the user.

In the FragmentList example you can find:

CheckBox check1;
boolean active;
@Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putBoolean("state1", check1.isChecked());
    }

Which you can use later like this:

@Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    if (savedInstanceState != null) {
            // Restore last state for checked position.
            check1.setChecked(savedInstanceState.getBoolean("state1"));
        }
}

But somehow the CheckBox elements don`t save their state.

Is this the correct approach I should take?