I was reading the doc, but I am still not too sure. Its says to use getContentResolver()
, but then that really isn't using CursorLoader. So is there a way to do it through CursorLoader
? I know how to do it with query()
. Are the steps very similar? Even just a link that explains exactly this would be helpful.
Please note, do not link me to the Google doc as they do not have an example that ever uses the insert()
method from ContentProvider using a CursorLoader
.
Thanks in advance!!
Edit: I should probably mention the reason I am confused with this is because calling a new CursorLoader
automatically calls ContentProviders
query()
method. But how can I do the same for insert?
Check out my blog post on the subject:
Content Resolvers and Content Providers
CursorLoader
has nothing to do with it.Insertion is a totally different concept... it has absolutely nothing to do with the CursorLoader
. When coupled with the LoaderManager
, the CursorLoader
automatically queries your database and updates itself when the ContentObserver
is notified of a datastore change. It has nothing to do with the actual process of inserting data into your database.
ContentResolver
are resolvedWhen you insert (or query or update or delete) data into your database via the content provider, you don't communicate with the provider directly. Instead, you use the ContentResolver
object to communicate with the provider (note that the ContentResolver
is a private instance variable in your application's global Context
) . More specifically, the sequence of steps performed is:
You call getContentResolver().insert(Uri, ContentValues);
The ContentResolver
object determines the authority of the Uri.
The ContentResolver
relays the request to the content provider registered with the authority (this is why you need to specify the authority in the AndroidManifest.xml
).
The content provider receives the request and performs the specified operation (in this case insert
). How and where the data is inserted depends on how you implemented the insert
method (ContentProvider
is an abstract class that requires the user to implement insert
, query
, delete
, update
, and getType
).
Hopefully you were able to wrap your head around that at least a little. The reason why there are so many steps involved is because Android (1) allows applications to have more than one content provider, and (2) needs to ensure that apps can securely share data with other third-party apps. (It wasn't because it wanted to confuse you, I promise).
ContentProvider
Now that you (hopefully) have a better idea of how the ContentResolver
is able to relay these requests to the content provider, inserting the data is fairly straight forward:
First, decide which uri you want to have matched by your content provider. This depends on how you decided to match your uris with the UriMatcher
. Each uri you have represents a different means of inserting data into your internal database (i.e. if your app has two tables, you will probably have two uris, one for each table).
Create a new ContentValues
object and use it to package the data you wish to send to the content provider. The ContentValues
object maps column names to data values. In the below example, the column name is "column_1" and the value being inserted under that column is "value_1":
ContentValues values = new ContentValues();
values.put("column_1", "value_1");
Once received, the content provider will (in your case) pass the values
object to your SQLiteDatabase
(via the SQLiteDatabase.insert(String table, String nullColumnHack, ContentValues values)
method). Unlike the ContentProvider
, this method is implemented for you... the SQLiteDatabase
knows how to handle the values
object and will insert the row into the database, returning the row id of the inserted row, or -1
if the insertion failed.
... and that's how you insert data into your database.
Use getContentResolver().insert(Uri, ContentValues);