Potential Compatibility Issue

[strooonger]

Hi, I notice in class RulesPreferenceFragment.java you have used function onAttach(Context), which is added in API version = 23. However, onAttach(Context) will not execute in API version < 23 (See this link).

Class RulesPreferenceFragment directly extends android.preference.PreferenceFragment. As the official document of Android shows, android.preference.PreferenceFragment directly extends android.app.Fragment, unfortunately in practice onAttach(Context) will not executed if one use android.app.Fragment. If you put some important operation into this function, the program may not execute normally in API<23.

My suggestion is simply changing android.preference.PreferenceFragment to android.support.v7.preference.PreferenceFragmentCompat, which have the same function as android.preference.PreferenceFragment, but does not have this potential compatibility issue.

[ukanth]

Thanks for the suggestion. Is it possible to make a pull request ?