Our MainStarter is extends the AbstractGame which is inital point of our game. This is constructed once and used until we exit the game, all screens managed by the game class.
SETTING APP SETTINGS
This is so important, AppSetting is our info depo which we get all static info about sizes. It is used in Scene2D Stage creation in AbstractScreen class. Also the we store the word and target world size to calculate DIPActive and use in World contructions.
It has 3 setUp() methods in it, you can just read the descriptions for those. You either use my DIPActive - anti stretch formula or you just use regulat libgdx development style which ends up scaling the stage due to device res. DIPActive is okay formula, but not awsome, for pixel/position perfect games it should be avoided, but it is very handy for live wallpapers.
Just use each setUP() method and run the game 480x320 and 960x540 resolutions in desktop, you will see the what I mean about stretching.
We create 2 text files as mini database after first install, and thats it.