I created two content providers that work on two different tables of the same SQLite database. They share a single instance of SQLiteOpenHelper
as described in the post of Ali Serghini. Each content provider is registered in AndroidManifest.xml
as follows.
<provider
android:name=".contentprovider.PostsContentProvider"
android:authorities="com.example.myapp.provider"
android:exported="false"
android:multiprocess="true" >
</provider>
<provider
android:name=".contentprovider.CommentsContentProvider"
android:authorities="com.example.myapp.provider"
android:exported="false"
android:multiprocess="true" >
</provider>
Each content provider defines the needed content URIs and supplies an UriMatcher
.
public class PostsProvider extends BaseContentProvider {
private static final UriMatcher sUriMatcher = buildUriMatcher();
private static final int POSTS = 100;
private static final int POST_ID = 101;
private static UriMatcher buildUriMatcher() {
final UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
final String authority = CustomContract.CONTENT_AUTHORITY;
matcher.addURI(authority, DatabaseProperties.TABLE_NAME_POSTS, POSTS);
matcher.addURI(authority, DatabaseProperties.TABLE_NAME_POSTS + "/#", POST_ID);
return matcher;
}
...
public class CommentsProvider extends BaseContentProvider {
protected static final UriMatcher sUriMatcher = buildUriMatcher();
protected static final int COMMENTS = 200;
protected static final int COMMENT_ID = 201;
private static UriMatcher buildUriMatcher() {
final UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);
final String authority = CustomContract.CONTENT_AUTHORITY;
matcher.addURI(authority, DatabaseProperties.TABLE_NAME_COMMENTS, COMMENTS);
matcher.addURI(authority, DatabaseProperties.TABLE_NAME_COMMENTS + "/#", COMMENT_ID);
return matcher;
}
When I invoke the content resolver to insert posts, the PostsContentProvider
is targeted. When I try to insert comments, however, the content resolver does not refer to the CommentsContentProvider
as expected, but calls upon the PostsContentProvider
. The result is the following exception which I throw in the PostsContentProvider
.
UnsupportedOperationException: Unknown URI: content://com.example.myapp.provider/comments
Is it possible to output all available content URIs currently registered with an content provider?
The android:authorities
needs to be unique for each content provider. The documentation is here
quoted from doc
The content: scheme identifies the data as belonging to a content provider and the authority (com.example.project.healthcareprovider) identifies the particular provider. The authority therefore must be unique.