Saving Data on Android

Implemen/ng delete
Deleting a record is simple. Open 
ToDoContentProvider.kt
 and copy the following 
code into the body of 
delete
 replacing the 
TODO
 statement:
return
 db.delete(parseLong(selectionArgs?.
get
(
0
)))
This gets the id for the record to delete out of the 
selectionArgs
 and pass that value 
to the database handler to delete the record from the underlying database. The
Saving Data on Android
Chapter 4: ContentProvider
raywenderlich.com
86

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number of rows that are deleted is returned.
Next open 
ToDoAdapter.kt
 and add this code to the body of 
deleteToDo
 replacing 
the comment:
// 1
 
selectionArgs = arrayOf(id.toString()) 
// 2
 
context.contentResolver.delete(Uri.parse(queryUri), 
selectionClause, selectionArgs) 
// 3
 
notifyDataSetChanged()
1. Populate 
selectionArgs
 with the id of the record to delete.
2. Run the query to delete the record.
3. Notify the adapter that the dataset has changed so the recyclerview will update.
Run the app, you are now able to delete items from the list. Great! Now you have 
created your very own content provider and content resolver in one. Even though it 
is not required to utilize a content provider when outside apps aren't accessing the 
data, sometimes it can provide an organizational layer of abstraction that can 
improve an app's overall architecture. Now, if you'd like, you can tackle an additional 
challenge and create a client app that will utilize the content provider.