Developers do not always have the knowledge needed to understand source code and must refer to different resources (e.g., teammates, documentation, the web). This non-trivial process, called program comprehension, is very time-consuming. While many approaches support the comprehension of a given code at hand, they are mostly focused on defining extractive summaries from the code (i.e., on selecting from a given piece of code the most important statements/comments to comprehend it). However, if the information needed to comprehend the code is not there, their usefulness is limited. We present ADANA, an approach to automatically inject comments describing a given piece of Android code. ADANA reuses the descriptions of similar and well-documented code snippets retrieved from various online resources. Our evaluation has shown that ADANA is able to aid the program comprehension process.