Loaders in Android
Introduction with Honeycomb
Where we can use?
1) to
access data of databases 2) content providers
They
load data asynchronously and notify the listeners when the results
are available/ready.
- They are available to every Activity and Fragment.
- They provide asynchronous loading of data.
- They monitor the source of their data and deliver new results when the content changes.
- They automatically reconnect to the last loader's cursor when being recreated after a configuration change. Thus, they don't need to re-query their data.
For
API please visit
http://developer.android.com/guide/components/loaders.html
the main classes and interfaces are as folllows
1)LoaderManager
= Manages
your Loaders for you. Responsible for dealing with the Activity or
Fragment lifecycle
2)Loader
=The
base class for all Loaders
3)LoaderManager.LoaderCallbacks
= A
callback interface you must implement
4)AsyncTaskLoader
= An
implementation that uses an AsynTask to do its work
5)CursorLoader
= A
subclass of AsyncTaskLoader for accessing ContentProvider data
eXample
please visit at github
and
https://github.com/emil10001/AndroidSerialSQL/tree/sample
(Source code)
Advantage==> Loaders in Android are great, they allow us to asynchronously load data to be used in Adapters. It is found that CursorLoaders very useful for getting data from a database to the UI in a way that minimizes blocking calls on the UI thread.
Google did not only introduce Loaders but also deprecated the previous way to handle a Cursor within your activities. You shouldn’t use
Advantage==> Loaders in Android are great, they allow us to asynchronously load data to be used in Adapters. It is found that CursorLoaders very useful for getting data from a database to the UI in a way that minimizes blocking calls on the UI thread.
Google did not only introduce Loaders but also deprecated the previous way to handle a Cursor within your activities. You shouldn’t use
startManagingCursor()or managedQuery() in your projects anymore.