Discussions

Scope and conventions:

• Assume local time zone (device time zone) for UI display
• No recurring events supported
• No attendees information
• Events can span multiple days
• All day events should end at midnight the next day, or any day after that, e.g.:
  • Mon 12:00 AM - Tue 12:00 AM for 1-day event
  • Mon 12:00 AM - Thu 12:AM for multi-day event
• A local calendar will be created if none exists, no functionality to edit or add calendars
• Simple coloring of events based on their calendar ID, from a pool of predefined colors
• Only sync weather for today and tomorrow (from forecast.io)
  • Sync once every 24h
  • Rely on last known location for simplicity
  • Cache using SharedPreferences for simplicity

Custom views:

• EventCalendarView: custom calendar view - extends ViewPager
  • mimic the look and feel of android.widget.CalendarView
  • each page is a custom RecyclerView view with a GridLayoutManager
  • shuffle and reuse pages as users swipe to minimize number of pages in memory
  • provide APIs for android.provider.CalendarContract.Events cursor binding for each page
  • provide APIs for controlling UI and interaction callbacks
• AgendaView: custom agenda view - extends RecyclerView
  • automatically prepend/append rows via scroll events
  • automatically prune adapter items to keep its size from growing infinitely
  • provide APIs for android.provider.CalendarContract.Events cursor binding for each row
  • provide APIs for controlling UI and interaction callbacks
• EventEditView: custom form view to create/edit event
• CalendarSelectionView: custom list view for calendar selection
• Content provider operations and coordination among views are handled by Activity

Layout arrangement:

• Portrait: more vertical space
  • Stack calendar view and agenda view
• Landscape: limited vertical space
  • For smaller devices, moderate horizontal space: overlap calendar view and agenda view. In this case the calendar view becomes more of a 'pop-up' picker
  • For larger devices e.g. tablets, more horizontal space: put calendar view and agenda view side-by-side

Data source:

• Use Calendar Provider, required API 14
• Pros:
  • Zero setup efforts needed for local storage
  • Can sync with other calendar apps that make use of the same provider
  • Work with a SyncAdapter to periodically sync to a remote data source
  • Inherit a well-defined model for calendars, events, attendees etc
• Cons:
  • Inflexible content observation, e.g. unable to set custom notification URI for individual observations
  • Become much more complex when having to join multiple tables, e.g. calendars, events, attendees
  • Tricky handling of all-day events, which are stored in UTC
• Some ideas (not implemented):
  • Create a custom content provider that wrap Calendar Provider
  • Abstract complex join queries, by creating SQL Views that get updated when underlying data from Calendar Provider change
  • Design a schema that is more tailored to UI design requirements

Testing:

• Chose Robolectric as I am already familiar and comfortable with it.
• Relax visibilities of several fields for testing convenience. These can be avoided with dependency injection but I just keep it simple here.

Weather icons are from Meteocons set by Alessio Atzeni