Context-aware smartphone applications refer to those that have the ability to discern information about their working environment and dynamically adapt their behaviors. Often, this involves extensive usage of sensors and other hardware components. As a result, these types of applications have been growing in popularity as developers and researchers discover new and creative ways to aggregate information into contextual data. Context-aware applications have the potential to change behavior based on the environment, compensate when certain hardware components are inaccurate or unavailable, track users’ activities, and generally extend the feature set of a smartphone. There is no “best” way to collect contextual information and, as such, context awareness is a multifaceted research field. In this paper, we present a survey of the recent research directions within context awareness for mobile platforms, specifically for the key fields of localization, movement and activity tracking, and environmental sensing. For each field, we cover significant work, common trends, typical approaches, tradeoffs, and possible future research directions.