Is "like" used as an adjective by native speakers?

You have to distinguish between transitive and intransitive uses of the adjective.

• Intransitive like, meaning “similar”, occurs only as an attributive (like minds, like considerations); in predicative positions it is replaced by alike (Their minds are alike). It is very rare in speech, and even in writing it is not common. The Google Ngram below, which plots the relative literary frequency of like and similar in a couple of shared contexts, is suggestive, nothing more; but I suspect that if anything it exaggerates the contemporary frequency of attributive like, perhaps because the use is still fairly popular in legal writing.

  

• Transitive like, meaning “similar to”, is very common in both speech and writing. The Google Ngram below shows that in writing it has lost ground to similar to over the past century; but my guess is that it is far more common in speech.

  

  Transitive like is never used as an attributive. You should be aware, too, that many authorities regard like in this context as a preposition rather than an adjective. It certainly behaves like a preposition; but so do adjectives like ready and worth. Use the analysis that fits your immediate need.

There are a handful of set expressions that are more or less common and where you might analyse that "like" is an adjective (though you could possibly analyse that it is a quantifier or other category):

• the phrase "of like mind" and corresponding compound "like-minded"
• the expression "compare like with like"
• in US usage, the legal phrase "like kind" and corresponding compound ("a property of like kind", "a like-kind exchange")

Otherwise, it is occasionally used in formal usage to mean 'similar to the other things mentioned' or 'similar to one another', usually with a plural noun:

"A family is a categorisation of like species."

"Carbon dioxide and other like compounds."