SEE, GAUSS LAW DEALS WITH A FLUX PASSING THROUGH ANY CLOSED SURFACE AND ACCORDING TO GAUSS IT ONLY DEPENDS UPON THE CHARGE ENCLOSED INSIDE THE SURFACE. SEE, EXACTLY U R GETTING CONFUSED COZ. WHILE APPLYING GAUSS LAW WE ALWAYS DRAW GAUSSIAN SURFACE ON WHICH IT IS SAID THT THE ELECTRIC FIELD MUST BE UNIFORM. BUT U HAVE TO UNDERSTAND THT IS IS DONE ONLY WHEN WE R SUPPOSED TO CALCULATE ELECTRIC FIELD AND THT CALCULATION IS ONLY AN APPLICATION OF GAUSS LAW NOT THE LAW ITSELF. THEREFORE GAUSS LAW DOES NOT BOTHER WHETHER ELECTRIC FIELD IS UNIFORM OR NOT , IT JUST DEALS WITH TOTAL FLUX PASSING WHICH ACCORDING TO IT ONLY DEPENDS UPON THE CHARGE ENCLOSED AND NOT ITS DISTRIBBUTION PATTERN. THUS, GAUSS LAW IS VALID FOR FOR UNIFORM AS WELL AS NON - UNIFORM ELECTRIC FIELD.
RATE IF SATISFIED OR U CAN ASK FOR FURTHER EXPLANATION.