What are Aristotle's views on reality?
One problem with trying to understand Aristotle's theory of "reality" is that the modern term does not necessarily correspond to any specific concept or word found in Aristotle. In fact, the popular sense of reality is vague enough that it can be somewhat of an obstacle to philosophical discourse unless explicitlt defined.
Two possible Aristotelian concepts which might address your question are "physis" (nature) and "ta onta" (beings, things that are). For Aristotle, as mentioned by Redscar, Metaphysics was the study of being qua being. The difficulty of this study is that for Aristotle, universals are not separated (there are no "forms") but rather for an substance to exist it must have qualities -- the only pure being is the unmoved mover. The nature, or physis, of all beings can be understood in terms of four causes, the material cause (the substance of an object), the final cause (its purpose), the formal cause (its form or nature) and the efficient cause (what made it)
While Plato was a clear-cut idealist, considering the phenomenal world unreal, Aristotle's views on the subject of reality is a bit more complex and more positive than Plato's too.
Aristotle's theory of 'mimesis' as the essential process and nature of all arts is in itself a position on reality and its representation. His views on mimesis is not negative. As he says, all great art, at a basic level, is an imitation of action.
But in Poetics, Aristotle developes three different premises in terms of characterization in a literary work--
1. Characters higher than those of reality---this can be termed an 'idealist' premise.
2. Characters lower than those of reality-- this can be called a deflatory and comical premise.
3. Characters as close as possible to those of reality--this can be termed a 'realistic' premise.