System Design Principles

This section provides an overview of MyRuns' system design principles. We use MVC as the architectural design pattern. Model–view–controller (MVC) is one of many software design patterns, which has been widely adopted to develop software architecture for user interfaces. The design consideration of MVC is to separate business logic from user interfaces. In what follows, the design of profile management and tracking are illustrated.

Profile Management

The design of the profile management is shown in the diagram below. As you can see from the previous section, the user can input, view, and change their profiles. The user profile contains items such as name, gender, photo, phone, gender, and class. Therefore,we can define a class to represent this data structure. This profile class also handles where to save the profile data and how to retrieve the profile data, which is transparent to other module. The profile definition is the model component in MVC.

We design the user interface in the profile activity layout. It defines how the profile data will be presented to the user and how the user update the profile in term of where they input the information and how they signal the system to save the profile. The profile activity layout is the view component in MVC.

The profile activity glues the profile definition and the user interface together: it get data from the profile definition then push the data to the profile activity layout to show the profile to the user; when the user click the Save button, the activity is signaled. It retrieve the updated data from the view and push it to the profile definition to save.

Tracking

Tracking is the most complex module on MyRuns, which is shown below.

As you can see from the diagram, the model has three sub-modules: tracking service, trace data structure, and trace database. The trace data structure defines what data is in a trace (e.g., GPS coordinates, time, duration, etc). All traces are saved in the trace database. The tracking service collect GPS coordinates as well as other trace related information.

The MapView layout defines how the trace data will be presented to the user. It shows the live location trace, as well as location traces from the history.

The MapView activity glues the user interface and the underline data structure, database, and tracking service together. If the user is tracking, the activity starts the tracking service, which creates an instance of the trace data structure. The service insert GPS coordinates to the trace instance, and notifies the activity, which, in turn, updates the MapView layout to show the latest location trace. After the user finished tracking, the activity stops the service, then save the trace instance to the database.

If the user want to view a trace from history, the MapView activity retrieve the record from the database, then updates the MapView layout to show the trace.

The implementation detail is described in later sections.