In This Chapter
An app that is successful in gaining user acceptance must meet two kinds of requirements: functional and nonfunctional. Functional requirements describe what the app must do (the functions it must perform). A wayfinding app, for example, must allow the user to plot a route from one location to another. As another example, the Tic-Tac-Toe application must show you a board and enable you to place Xs and Os on it. These functional requirements describe what is needed to “build the right app.”
While most developers realize that their apps must implement these functional requirements, they don't focus enough effort on meeting nonfunctional requirements, which mandate how the app must do what it does. Nonfunctional requirements provide guidelines on how to “build the app right.”
In this chapter, we focus on nonfunctional requirements and identify three that apply especially to Android apps: performance, battery conservation, and responsiveness. We then show you ways in which to meet these nonfunctional requirements.
It's a statement worth repeating: Nonfunctional requirements (NFR) — also known as quality requirements or design requirements — provide guidelines on how to build an app right. For example, you might consider it appropriate ...