This is project #2 from the udacity android nano degree program. The project requirements are online.
The app source is divided into data, ui, and sync. I'll cover each in turn.
I am not an artsy GUI person, so this won't win any design awards. I took this as a learning project to pick up how to write a ContentProvider, a SyncAdapter, various Fragment based Activities that handle both the Activity and Fragment life cycles. I took some care to make sure no database query() or insert() calls were made on the UI thread.
The data section is an SQLite content provider. The database schema:
The three main lists that are displayed are favorites, popular, and toprated. In each case,
we return a movies inner joined with the list based on the mid in each table and
movies left joined with the favorites list. This allows the details view access to all of the
data it needs with a single cursor.
Bulk inserts are supported within a single transaction, which speeds up android devices considerably.
I try to minimize the number of moviedb api calls. We prefetch the popular and toprated lists
but don't prefetch reviews or trailers as this would require two api calls per movie. Instead
we fetch and cache reviews (.data.ReviewLoader) and trailers (.data.TrailerLoader) on demand.
Genre names are loaded and cached (.data.GenreNameMapper)from the moviedb once after
initial installation.
The .data.Contract class contains interfaces that describe the column names, indices, and
default projections in the joined tables returned on calls to query(). It also has static
functions that return fluent builders for the ContentValues needed for insert().
The sync package is pretty simple.
The .sync.StubAuthenticatorService that I can reuse in other projects. I should have put it
in a generic package, but I can just change the package name when I reuse the class.
The .sync.MoviesSyncService is just a couple of lines of code to create a MoviesSyncAdapter or
an IBinder.
.sync.MoviesSyncAdapter contains all of the real code for synchronization. The moviedb api
returns 20 movies per page when fetching the toprated or popular lists. By default,
MoviesSyncAdapter will fetch 5 pages at a time from each list up to a MAX_PAGE=50. Every
SYNC_FLEXTIME (6 hrs +- 3hrs). An initial sync happens on application startup. All network
api calls are made using retrofit2.
I really like RecyclerView, but there is no RecyclerView.Adapter for Cursor. I grabbed
some stuff off of stackoverflow and subclassed RecyclerView.Adapter for a
.ui.RecyclerViewCursorAdapter. I'm using this for both the posters grid layout and for
the individual pages of the details view.
I like the support.v4.view.ViewPager. However, it won't take a RecyclerView.Adapter and the
2K+ detail fragments in memory didn't sound like a good idea.
For the details fragment I am doing a full page ScrollView for the individual details pages
and putting it in a RecyclerView with a horizontal LinearLayoutManager
using the local .ui.RecyclerViewCursorAdapter.
This seems to do what you would want. If you scroll up or down, you can see all of the details on a small screen. Scrolling side to side brings in details of different movies. Side to side scroll is infinite (up to the number of movies).
A view pager locks in full pages on the screen by snapping them into place. I like that behavior
so I'm doing it here by subclassing RecyclerView.OnScrollListener and using it to snap
full details pages into place when the scrolling has stopped.
Details and Posters are Fragments with retainInstance true, so they should go through rotations fine or jumping to other activities and back.
Reviews and trailers are both displayed in very simple ListActivities that are kicked off by buttons in the Details fragment. I didn't want to put details and trailers directly in the DetaislFragment because that would kick off network API calls for every detail that we looked at. Just bring them if somebody cares.
I'm using Glide to load thumbnails and such for posters or details images.
Rather than fix the number of columns in the PostersFragment, I fix the column width in dp, scale to pixels and have a GridAutoFitLayoutManager subclass of GridLayoutManager. The number of columns in the PostersFragment will vary from device to device.
As you scroll through either the gallery or the details fragments on a tablet, the other fragment is scrolled to the same position.
Tablet shots:
Cell shots:
Lot's of things come to mind:
- We should prune the database if/when it gets too big.
- We should fetch new genre names occasionally.
- Once we get trailers/reviews and cache them, we don't fetch them again. Should do that at some point.
- Should do a settings activity to control (among other things) when and how much data fetching to do.
- I should hook in stetho and do some more analysis.
- General code cleanup. Get rid of a lot of the useless logging.