Does American English adhere to the double negative law?

I hear so many U.S. Celebrities; news reporters; song writers and even politicians using double negatives. Does the same rule apply in the American version of English wherein a double negative is indeed a positive?

i.e. “I didn’t do nothing” = (I’ve done something)
&
“You ain’t heard nothin’ yet, folks!” = (You’ve heard something, folks)