The document discusses content providers in Android. It describes the overall structure of content providers and how they allow sharing of data across applications. It covers interacting with content providers using content resolvers, constructing queries, retrieving cursors asynchronously using loaders or async query handlers. It also discusses provider permissions and creating a content provider by implementing methods like query, insert, update and delete and matching URIs.

1. Content Providers in Android

2. ●
Overall structure
●
Interaction with Content Provider
●
Constructing query
●
Retreiving cursor asyncronuously
●
Provider permissions
●
Creating Content Provider
●
Questions

3. ●
Overall structure
●
Interaction with Content Provider
●
Constructing query
●
Retreiving cursor asyncronuously
●
Provider permissions
●
Creating Content Provider
●
Questions

4. Overall structure
Application #2
Application #1
Activity #1
Activity #1
Activity #2 Content Provider Application #3
Activity #3 Activity #1
Activity #2
Remote
Database Files XML …
connection

5. Content Provider is a source
Application #2
Application #1
Activity #1
Activity #1
Activity #2 Content Provider Application #3
Activity #3 Activity #1
Activity #2
Remote
Database Files XML …
connection

6. For some consumers
Application #2
Application #1
Activity #1
Activity #1
Activity #2 Content Provider Application #3
Activity #3 Activity #1
Activity #2
Remote
Database Files XML …
connection

7. Gives access to variety types of data
Application #2
Application #1
Activity #1
Activity #1
Activity #2 Content Provider Application #3
Activity #3 Activity #1
Activity #2
Remote
Database Files XML …
connection

8. Overall structure
Application #2
Application #1
Activity #1
Activity #1
Activity #2 Content Provider Application #3
Activity #3 Activity #1
Activity #2
Remote
Database Files XML …
connection

9. ●
Overall structure
●
Interaction with Content Provider
●
Constructing query
●
Retreiving cursor asyncronuously
●
Provider permissions
●
Creating Content Provider
●
Questions

10. Interaction with Content Provider
Application #2
Application #1
Activity #1
Activity #1
Activity #2 Content Provider Application #3
Activity #3 Activity #1
Activity #2
Remote
Database Files XML …
connection

11. Activity to Content Provider access
Activity
Cursor ContentResolver Content Provider
CursorAdapter ListView

12. Activity
Activity
Cursor ContentResolver Content Provider
CursorAdapter ListView

13. Performing request
Content Provider
Query
Insert
ContentResolver URI
Update
Delete

14. URI
content://com.example.provider/articles
Scheme Authority Path

15. ●
Overall structure
●
Interaction with Content Provider
●
Constructing query
●
Retreiving cursor asyncronuously
●
Provider permissions
●
Creating Content Provider
●
Questions

16. Constructing query
SELECT _id, title, content, date
FROM articles
WHERE date >= 1352470000
ORDER BY date ASC

17. Constructing query
String[] mProjection =
{
"_id",
"title",
"content",
"date",
};
String mSelection = "date >= ?";
String[] mSelectionArgs = {"1352470000"};
String mSortOrder = "date ASC";
Cursor cursor = getContentResolver().query(
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);

18. Constructing query
String[] mProjection =
{
"_id",
"title",
"content",
"date",
};
String mSelection = "date >= ?";
String[] mSelectionArgs = {"1352470000"};
String mSortOrder = "date ASC";
Cursor cursor = getContentResolver().query(
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);

19. Constructing query
String[] mProjection =
{
"_id",
"title",
"content",
"date",
};
String mSelection = "date >= ?";
String[] mSelectionArgs = {"1352470000"};
String mSortOrder = "date ASC";
Cursor cursor = getContentResolver().query(
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);

20. Constructing query
String[] mProjection =
{
"_id",
"title",
"content",
"date",
};
String mSelection = "date >= ?";
String[] mSelectionArgs = {"1352470000"};
String mSortOrder = "date ASC";
Cursor cursor = getContentResolver().query(
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);

21. Constructing query
String[] mProjection =
{
"_id",
"title",
"content",
"date",
};
String mSelection = "date >= ?";
String[] mSelectionArgs = {"1352470000"};
String mSortOrder = "date ASC";
Cursor cursor = getContentResolver().query(
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);

22. Constructing query
String[] mProjection =
{
"_id",
"title",
"content",
"date",
};
String mSelection = "date >= ?";
String[] mSelectionArgs = {"1352470000"};
String mSortOrder = "date ASC";
Cursor cursor = getContentResolver().query(
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);

23. Cursor
_id title content date
1 First article Lorem ipsum... 1352475013
2 Second article Dolor sit amet... 1352471413
... ... ... ...
if (mCursor != null) {
while (mCursor.moveToNext()) {
String title = mCursor.getString(Columns.TITLE);
}
}

24. ●
Overall structure
●
Interaction with Content Provider
●
Constructing query
●
Retreiving cursor asyncronuously
●
Provider permissions
●
Creating Content Provider
●
Questions

25. Activity & blocking queries
Activity
Cursor ContentResolver Content Provider
CursorAdapter ListView

26. Activity & non blocking queries
Activity
CursorLoader
Cursor ContentResolver
Content Provider
AsyncQueryHandler
CursorAdapter ListView

27. Activity & Loader
Activity
CursorLoader
Cursor ContentResolver
Content Provider
AsyncQueryHandler
CursorAdapter ListView

28. Activity & Loader
public class ArticlesActivity extends FragmentActivity implements
LoaderCallbacks<Cursor> {
...
getSupportLoaderManager().initLoader(0, null, this);
...
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new CursorLoader(
this, // context
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);
}
public void onLoadFinished(
Loader<Cursor> loader,
Cursor cursor) {
mAdapter.swapCursor(cursor);
}

29. Activity & Loader
public class ArticlesActivity extends FragmentActivity implements
LoaderCallbacks<Cursor> {
...
getSupportLoaderManager().initLoader(0, null, this);
...
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new CursorLoader(
this, // context
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);
}
public void onLoadFinished(
Loader<Cursor> loader,
Cursor cursor) {
mAdapter.swapCursor(cursor);
}

30. Activity & Loader
public class ArticlesActivity extends FragmentActivity implements
LoaderCallbacks<Cursor> {
...
getSupportLoaderManager().initLoader(0, null, this);
...
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new CursorLoader(
this, // context
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);
}
public void onLoadFinished(
Loader<Cursor> loader,
Cursor cursor) {
mAdapter.swapCursor(cursor);
}

31. Activity & Loader
public class ArticlesActivity extends FragmentActivity implements
LoaderCallbacks<Cursor> {
...
getSupportLoaderManager().initLoader(0, null, this);
...
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new CursorLoader(
this, // context
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);
}
public void onLoadFinished(
Loader<Cursor> loader,
Cursor cursor) {
mAdapter.swapCursor(cursor);
}

32. Activity & Loader
public class ArticlesActivity extends FragmentActivity implements
LoaderCallbacks<Cursor> {
...
getSupportLoaderManager().initLoader(0, null, this);
...
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new CursorLoader(
this, // context
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);
}
public void onLoadFinished(
Loader<Cursor> loader,
Cursor cursor) {
mAdapter.swapCursor(cursor);
}

33. Activity & AsyncQueryHandler
Activity
CursorLoader
Cursor ContentResolver
Content Provider
AsyncQueryHandler
CursorAdapter ListView

34. Activity & AsyncQueryHandler
private AsyncQueryHandler mHandler;
...
mHandler = new MyAsyncQueryHandler(getContentResolver());
mHandler.startQuery(
0, // token
null, // cookie
MyContentProvider.ARTICLES_CONTENT_URI,
mProjection,
mSelection,
mSelectionArgs,
mSortOrder);

35. Activity & AsyncQueryHandler
class MyAsyncQueryHandler extends AsyncQueryHandler {
public MyAsyncQueryHandler(ContentResolver cr) {
super(cr);
}
@Override
protected void onQueryComplete(
int token,
Object cookie,
Cursor cursor) {
mAdapter.swapCursor(cursor);
}
}

36. ●
Overall structure
●
Interaction with Content Provider
●
Constructing query
●
Retreiving cursor asyncronuously
●
Provider permissions
●
Creating Content Provider
●
Questions

37. Permissions
<permission
android:name="com.example.provider.permission.READ_ARTICLES"
android:protectionLevel="normal" />
<provider android:name=".MyContentProvider"
android:exported="false"
android:authorities="com.example.provider"
android:permission="com.example.provider.permission.READ_ARTICLES"
/>
<uses-permission
android:name="com.example.provider.permission.READ_ARTICLES" />

38. Permissions
<permission
android:name="com.example.provider.permission.READ_ARTICLES"
android:protectionLevel="normal" />
<provider android:name=".MyContentProvider"
android:exported="false"
android:authorities="com.example.provider"
android:permission="com.example.provider.permission.READ_ARTICLES"
/>
<uses-permission
android:name="com.example.provider.permission.READ_ARTICLES" />

39. Permissions
<permission
android:name="com.example.provider.permission.READ_ARTICLES"
android:protectionLevel="normal" />
<provider android:name=".MyContentProvider"
android:exported="false"
android:authorities="com.example.provider"
android:permission="com.example.provider.permission.READ_ARTICLES"
/>
<uses-permission
android:name="com.example.provider.permission.READ_ARTICLES" />

40. ●
Overall structure
●
Interaction with Content Provider
●
Constructing query
●
Retreiving cursor asyncronuously
●
Provider permissions
●
Creating Content Provider
●
Questions

41. Creating content provider
public class MyContentProvider extends ContentProvider {
...
onCreate()
query()
insert()
update()
delete()
getType()

42. URI matching
content://com.example.provider/articles
content://com.example.provider/articles/*
content://com.example.provider/articles/#

43. URI matching
content://com.example.provider/articles
content://com.example.provider/articles/*
content://com.example.provider/articles/#

44. URI matching
content://com.example.provider/articles
content://com.example.provider/articles/*
content://com.example.provider/articles/#

45. URI matching
sUriMatcher.addURI("com.example.provider", "articles/#", 0);
sUriMatcher.addURI("com.example.provider", "articles/today", 1);
sUriMatcher.addURI("com.example.provider", "articles/history/*", 2);
...
public String getType(Uri uri) {
switch (sUriMatcher.match(uri)) {
...

46. URI matching
sUriMatcher.addURI("com.example.provider", "articles/#", 0);
sUriMatcher.addURI("com.example.provider", "articles/today", 1);
sUriMatcher.addURI("com.example.provider", "articles/history/*", 2);
...
public String getType(Uri uri) {
switch (sUriMatcher.match(uri)) {
...

47. MIME types
getType()
vnd.android.cursor.dir/vnd.com.example.provider.article
vnd.android.cursor.item/vnd.com.example.provider.article
getStreamTypes()
{ "image/jpeg", "image/png", "image/gif" }

48. MIME types
getType()
vnd.android.cursor.dir/vnd.com.example.provider.article
vnd.android.cursor.item/vnd.com.example.provider.article
getStreamTypes()
{ "image/jpeg", "image/png", "image/gif" }

49. Questions
Thank you!

50. Useful links
http://developer.android.com/guide/topics/providers/content-provider-basics.html
http://developer.android.com/guide/topics/providers/content-provider-creating.html
http://developer.android.com/guide/topics/security/permissions.html
http://gdg.org.ua
http://dnipro.gdg.org.ua

51. About speaker
Alexey Ustenko — Android developer
Coordniator of GDG Dnipropetrovs'k
@ustav