Android: show / hide preference when checking / unchecking another CheckBoxPreference

I am trying to accomplish such a thing: when I check CheckBoxPreference 'A', another preference ('B') is displayed below A, when I uncheck "A", preference "B" is hidden ...

So generally speaking, it should work just like a dependency, but not only enable / disable preference B, but also hide it.

Here is what I came up with:

prefA = (CheckBoxPreference)findPreference("preference_A");
prefA.setChecked(false);

prefB = findPreference("preference_B");
category.removePreference(prefB);

prefA.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {

    @Override
    public boolean onPreferenceChange(Preference preference, Object newValue) {

        boolean switchedOn = (Boolean)newValue;
        if (switchedOn)
        {
            Log.d("pref_test", "prefA checked");

            category.addPreference(prefB);
        }
        else
        {
            Log.d("pref_test", "prefA UNchecked");

            prefB = findPreference("preference_B");
            category.removePreference(prefB);   
        }

        return switchedOn;  
    }
});

prefA and prefB were previously defined as fields of the PreferenceFragment class.

The problem is that it works just fine in 2 clicks, and my logs say:

prefA checked
prefA UNchecked
prefA UNchecked

As if he had called onPreferenceChangeListener twice to uncheck it (obviously .removePreference (prefB) method returned null).

Any idea to solve the problem?