Showing Revision 15 created 05/24/2016 by Udacity Robot.

1. Title:
   Why Content Providers Matter - Developing Android Apps
2. Description:

3. 470 0:00 - 0:02
   Before we go ahead and build a content provider
4. 2400 0:02 - 0:05
   you wouldn't be out of line to ask, well why.
5. 7250 0:07 - 0:09
   The simplest answer is that it allows you to
6. 9060 0:09 - 0:13
   share your data safely and efficiently across app boundaries by
7. 12540 0:13 - 0:16
   abstracting the underlying data source, be it SQLite like
8. 15520 0:16 - 0:19
   this or files or really anything else. So that other
9. 19080 0:19 - 0:22
   apps can access it without really needing to understand how
10. 21870 0:22 - 0:26
    you stored it. In fact, the calendar, SMS, and contacts
11. 25650 0:26 - 0:30
    APIs work that way, using shared content providers.
12. 29620 0:30 - 0:32
    We're going to share our weather database later, but if
13. 31780 0:32 - 0:34
    you're not planning to expose your app's data, you're
14. 34370 0:34 - 0:38
    probably thinking you can skip this bit, right? Well,
15. 38160 0:38 - 0:41
    almost, in a lot of cases you could,
16. 40770 0:41 - 0:45
    but really shouldn't. For example, in Sunshine we're using
17. 44970 0:45 - 0:47
    SQ Lite. But you could be storing data in
18. 47380 0:47 - 0:51
    files, dynamic run-time data or even just a different
19. 50680 0:51 - 0:55
    database library. By using content providers, it's easier for
20. 55040 0:55 - 0:57
    you to potentially switch out the data source and
21. 57380 0:57 - 1:00
    much easier for someone other than you to manage
22. 59740 1:00 - 1:02
    the UI layer code without them having to understand
23. 62410 1:02 - 1:05
    the depths of your data storage implementation. On the
24. 65459 1:05 - 1:09
    UI layer, it's a generic mechanism that returns cursors.
25. 69070 1:09 - 1:12
    The same of those returned by SQLite databases. So,
26. 72270 1:12 - 1:16
    if your data layer implementation changes, then your content provider
27. 75690 1:16 - 1:19
    is effected. Still, it's just you writing the code right
28. 79390 1:19 - 1:22
    now and that's a lot of boilerplate for the sake of
29. 81520 1:22 - 1:25
    following a neat design pattern. Well, keep in mind that
30. 84690 1:25 - 1:28
    as far as the framework is concerned, all data is handled
31. 87730 1:28 - 1:31
    through content providers. So, if you want to interact with
32. 91027 1:31 - 1:34
    anything outside of your app, such as sending data to a
33. 93790 1:34 - 1:38
    widget or returning search results from the newer app, you'll need
34. 97770 1:38 - 1:41
    a content provider for that too. In fact, that's how the
35. 100770 1:41 - 1:44
    Google play store and Gmail widgets work. As well as the
36. 103760 1:44 - 1:48
    ability to get search results from Google Play. Similarly, there's a bunch
37. 107920 1:48 - 1:52
    of APIs designed to optimize the process of synching and querying data,
38. 111960 1:52 - 1:57
    and updating UI accordingly. And all of them also expect content providers.
39. 120490 2:00 - 2:04
    That includes sync adapters and cursor loaders. Which make your
40. 123950 2:04 - 2:07
    app able to efficiently sync with your server, load data in
41. 127140 2:07 - 2:10
    your UI layer, and which include built in content observers that
42. 130360 2:10 - 2:14
    will update your UI automatically when the underlying data changes. You
43. 134167 2:14 - 2:18
    could, of course, build all of that yourself but at
44. 137680 2:18 - 2:20
    a certain point the advantage you gained by not writing a
45. 140350 2:20 - 2:23
    content provider to begin with is lost in the process of
46. 143280 2:23 - 2:27
    having to recreate all of the useful clusters that utilize it.
47. 146900 2:27 - 2:30
    We'll take a look at publishing your content provider and using Lotus
48. 150160 2:30 - 2:34
    to access it efficiently later in this lesson. And we'll explore sync adapters
49. 153980 2:34 - 2:38
    in lesson six when we look at doing efficient background updates. But
50. 157820 2:38 - 2:41
    first, Dan is going to show you how to actually build a content provider.