It's about how to change from an activity based approach to a fragment based one : 
(1) for RecyclerView action mode (p.1622) 
and (2) a custom DialogPreference preferences dialog (p.1991) for an often used filter.

(1) Why : it's a cascaded detail view (of 1|-> many) on database tables, simple example : LastName |-> cities |-> street |-> full adresses.
So I want to be able on tablets to see two fragment parts (ex. cities with all streets for the selected city (single selection action mode) 
 
(1) Works mostly, my approach was to move everything that needed it (receive/pass intent; RecyclerView; FragmentAdapter based on abstract FragmentBaseAdapter; ViewHolder) 
to the fragment and reference "fragment.getActivity()" to keep the references to the activity where necessary. 
But I can't get the action mode code to work. (The code is not traversed when I put a breakpoint in debug mode).
If I move the code to an OptionsMenu it works fine, but then the actionbar clearly is an optionsmenu and not an actionmenu, 
so I think I've missed "taking a Trick", as we say when playing Whist.

(2) Why : I want to launch a single filter dialog that's often used from a menu; and for the CWAC Colormixer example lint says xml based preferences approach is deprecated.
BTW: Is deprecation the team sport at android dev ;-) ?
The filter is a seekbar + gradual text explanation (so some values have the same text) 
i.e. "everything vaguely similar / loose ressemblance /stricter ressemblance / exact match only"

(2) I have it working now by passing through the preference activity with the intent, which launches the layout (with the XML) that contains the fragment. 
Can a DialogPreference fragment be launched from a normal activity, or should I use a normal dialog that's accessing shared preferences for this ?

In android studio, the Lint popup says "addPreferencesFromResource(R.xml.preferences)" is deprecated,and if you follow the link to the preferenceactivity class : 
     * @deprecated This function is not relevant for a modern fragment-based
     * PreferenceActivity.

Ok, guess it's worth to dive into that book more profoundly as well then 
(Only skimmed it for now, as I'm not using Room for my app

Maybe my wording was wrong, but I indeed meant how to script for debug builds, so this 
if (name.equals(com.android.builder.core.BuilderConstants.DEBUG)) {
            return; // Skip debug builds.
} 
part, is what I was looking for.

Yes, that's a good hint.

Second problem is gradle and the jacoco plugin issues with a specific library dependency: 
to be clear, on Github even the Gradle and Jacoco people refer to each-other for how to fix, 
so I know it's not a solution, but more of a possible problem-approach I'm looking for.
So normally, you can script gradle to exclude classes from the jacoco coverage, 
but it still touches the code excluded(adds jacoco related variables in intermediate class files)
 even if it shouldn't and that messes up the library's checks and balances and fails the compile.
So my question is: is there a way to "debug" gradle scripts, to check what it does / doesn't skip ?

Ok, maybe to round up a question that probably has such a simple answer that the answer is right in front of my nose, but I can't seem to find it: I'm using style windowFullscreen/ windowNoTitle, but I'm still getting my app name in every action/menubar, what have I overlooked?