I am not sure if this is a total stupid question and that I just do not see it but I just get it.
Apple has this nice shiny button used on several occasions, e.g. stop-watch

Now, how can you create those buttons ? In code and Interface Designer ?
Or is it only possible by using images for the different button states ?
Thanks.
There are numerous samples available online.
Try these ones:-
cool-tool-for-quickly-making-glossy-ios-buttons
drawing-gloss-gradients
Gradient Button
I hope, it helps