Android content providers
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Content providers allow sharing of data between Android applications. They encapsulate data and expose it through a single ContentResolver interface. When an app wants data from another app, it uses a content URI and the ContentResolver to request data from the target app's registered ContentProvider. The ContentProvider then uses the URI to find and return the requested data to the requesting app via the ContentResolver. To create a ContentProvider, an app defines an authority, extends ContentProvider, implements required methods like query(), and registers the provider in the manifest.
![android.content.ContentResolver
public final Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)
Query
insert(Uri url, ContentValues values)
INSERT
update(Uri uri, ContentValues values, String where, String[] selectionArgs)
Update
delete(Uri url, String where, String[] selectionArgs)
Delete](https://image.slidesharecdn.com/androidcontentproviders-151009111813-lva1-app6891/85/Android-content-providers-7-320.jpg)
![android.content.ContentResolver
public final Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)
Query
insert(Uri url, ContentValues values)
INSERT
update(Uri uri, ContentValues values, String where, String[] selectionArgs)
Update
delete(Uri url, String where, String[] selectionArgs)
Delete](https://image.slidesharecdn.com/androidcontentproviders-151009111813-lva1-app6891/85/Android-content-providers-10-320.jpg)
![android.content.ContentResolver
public final Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)
Query
insert(Uri url, ContentValues values)
INSERT
update(Uri uri, ContentValues values, String where, String[] selectionArgs)
Update
delete(Uri url, String where, String[] selectionArgs)
Delete](https://image.slidesharecdn.com/androidcontentproviders-151009111813-lva1-app6891/85/Android-content-providers-11-320.jpg)
![android.content.ContentResolver
public final Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)
Query
insert(Uri url, ContentValues values)
INSERT
update(Uri uri, ContentValues values, String where, String[] selectionArgs)
Update
delete(Uri url, String where, String[] selectionArgs)
Delete](https://image.slidesharecdn.com/androidcontentproviders-151009111813-lva1-app6891/85/Android-content-providers-13-320.jpg)
![Type - public String getType(Uri uri)
Delete - public abstract int delete (Uri uri, String selection, String[] selectionArgs)
Update - public abstract int update (Uri uri, ContentValues values, String selection, String[] selectionArgs)
Insert - public abstract Uri insert (Uri uri, ContentValues values)
3: Create your ContentProvider : Other Methods](https://image.slidesharecdn.com/androidcontentproviders-151009111813-lva1-app6891/85/Android-content-providers-18-320.jpg)
Android content providers
- 1. Android Content Providers Kurt Mbanje : DStv Digital Media +KurtMbanje @ckurtm
- 2. What's a Content Provider? • They provide content to applications. • They encapsulate data and provide it to applications through the single ContentResolver interface
- 3. Why? • Share data between applications. • Predictive search within your app • Leverage power of loaders with cursors.
- 4. Ok so how does this work? App 1 has content (database) and a registered ContentProvider App 2 uses ContentResolver and content Uri to request data from a ContentProvider Android uses the Uri provided by App 2 to find the matching registered ContentProvider to send and receive data from The ContentProvider for App 1 uses this Uri to find the data and returns it to the ContentResolver supplied by App 2
- 6. Content Uri android.net.Uri • The scheme – content:// • Authority • Path usually matches a table name in your database • ID (optional) used for further filtering e.g. to get a specific row
- 7. android.content.ContentResolver public final Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) Query insert(Uri url, ContentValues values) INSERT update(Uri uri, ContentValues values, String where, String[] selectionArgs) Update delete(Uri url, String where, String[] selectionArgs) Delete
- 10. android.content.ContentResolver public final Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) Query insert(Uri url, ContentValues values) INSERT update(Uri uri, ContentValues values, String where, String[] selectionArgs) Update delete(Uri url, String where, String[] selectionArgs) Delete
- 11. android.content.ContentResolver public final Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) Query insert(Uri url, ContentValues values) INSERT update(Uri uri, ContentValues values, String where, String[] selectionArgs) Update delete(Uri url, String where, String[] selectionArgs) Delete
- 12. Example: Update event in Calendar
- 13. android.content.ContentResolver public final Cursor query (Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) Query insert(Uri url, ContentValues values) INSERT update(Uri uri, ContentValues values, String where, String[] selectionArgs) Update delete(Uri url, String where, String[] selectionArgs) Delete
- 14. Create a Content Provider 1. Create an Authority 2. Create a your class that extends from ContentProvider 3. Implement the matching ContentResolver methods 4. Register your ContentProvider in manifest & mark export to true (only if you wish to share your data)
- 15. 1: Create an Authority
- 16. 2: Create your ContentProvider 1. Extend From ContentProvider 2. Implement OnCreate 3. Create your Uri matcher 4. Overide methods e.g. query
- 17. 3: Create your ContentProvider : Query Method
- 18. Type - public String getType(Uri uri) Delete - public abstract int delete (Uri uri, String selection, String[] selectionArgs) Update - public abstract int update (Uri uri, ContentValues values, String selection, String[] selectionArgs) Insert - public abstract Uri insert (Uri uri, ContentValues values) 3: Create your ContentProvider : Other Methods
- 19. 4: Register your ContentProvider