Hi tigrot, thanks for answer.
osmdroid solution probably are the best for my project. But i need to know how to use offline maps, what kind of conversion i have to made. I didn't found how to let osmdroid work despite a very explanative post by his author. My maps are quite little, so in GIS aplications i could have just one raster file. If i right understand, when i make the sqlitedb file it contains both the tiles suddivision of raster image and the correct geographics parameters of the map. But i'm not able to use it with osmdroid...