Yeast problem

On my first brewing trial, all is well only the co2 bubbles in the air trap stopped after 24 hrs.
Please advise :-\

what is the fermentation temp?
what kind of beer?
what is the gravity?
what yeast?
Do you see stuff swirling around in the fermenter (if it is clear and not opaque white bucket).

Fermentation happens even though you are not seeing CO2 bubble.  I expect activity three or so days. 

quite often the  initial stages of fermentation are so aggressive that it's all done within a day or so and after that it seems really slow.
Absent you dropping the temperature of your brew to like 35 degrees or so  and cold crashing the little buggers, there's nothing wrong with your yeast.

What temps were you fermenting at and wha yeast were you using?

If you fermented too warm it may have fermented quickly and depending on the yeast you used may have some off flavors.

As mentioned above, if you chilled your beer too quickly you have have cold shocked your yeast in which case I would just bring the temp up and see what happens.

Might not be a problem at all.  You might be done with the primary.  You might have a leak in the cover.
Give it a week.