Dependencies and prerequisites
- Android 1.6 or later
You should also read
Try it out
ThreadSample.zip
Querying a ContentProvider
for data you want to display takes time.
If you run the query directly from an Activity
, it may get blocked and
cause the system to issue an "Application Not Responding" message. Even if it doesn't, users
will see an annoying delay in the UI. To avoid these problems, you should initiate a query on a
separate thread, wait for it to finish, and then display the results.
You can do this in a straightforward way by using an object that runs a query asynchronously in
the background and reconnects to your Activity
when it's finished. This
object is a CursorLoader
. Besides doing the initial
background query, a CursorLoader
automatically re-runs the
query when data associated with the query changes.
This class describes how to use a CursorLoader
to run a
background query. Examples in this class use the v4 Support Library
versions of classes, which support platforms starting with Android 1.6.
Lessons
- Running a Query with a CursorLoader
-
Learn how to run a query in the background, using a
CursorLoader
. - Handling the Results
-
Learn how to handle the
Cursor
returned from the query, and how to remove references to the currentCursor
when the loader framework re-sets theCursorLoader
.