12.2. Mapping out the application flow

Have you ever downloaded an application’s source code, excited to get access to all that code, but found it overwhelming to navigate? You want to make your own changes, to put your own spin on the code, but you unzip the file into all the various subdirectories, and you don’t know where to start. Before we jump directly into examining the source code, we need to pay attention to the architecture, in particular the flow from one screen to the next.

12.2.1. Mapping out the field service application

In this section, we’ll examine the application flow to better understand the relation among the application’s functionality, the UI, and the classes used to deliver this functionality. Doing this process up-front helps ensure that the application delivers the needed functionality and assists in defining which classes we require when it comes time to start coding (which is soon)! Figure 12.3 shows the relation between the high-level classes in the application, which are implemented as an Android Activity, as well as interaction with other services available in Android.