ContentProvider

After being instantiated, this is called to tell the content provider about itself.

Implement this to insert a set of new rows, or the default implementation will iterate over the values and call insert(Uri, ContentValues) on each of them. As a courtesy, call notifyChange() after inserting. This method can be called from multiple threads, as described in Application Fundamentals: Processes and Threads.

A request to delete one or more rows. The selection clause is applied when performing the deletion, allowing the operation to affect multiple rows in a directory. As a courtesy, call notifyDelete() after deleting. This method can be called from multiple threads, as described in Application Fundamentals: Processes and Threads.

The implementation is responsible for parsing out a row ID at the end of the URI, if a specific row is being deleted. That is, the client would pass in content://contacts/people/22 and the implementation is responsible for parsing the record number (22) when creating a SQL statement.

Retrieve the Context this provider is running in. Only available once onCreate(Map icicle) has been called -- this will be null in the constructor.

Return the name of the permission required for read-only access to this content provider. This method can be called from multiple threads, as described in Application Fundamentals: Processes and Threads.

Return the MIME type of the data at the given URI. This should start with vnd.android.cursor.item for a single record, or vnd.android.cursor.dir/ for multiple items. This method can be called from multiple threads, as described in Application Fundamentals: Processes and Threads.

Return the name of the permission required for read/write access to this content provider. This method can be called from multiple threads, as described in Application Fundamentals: Processes and Threads.

Implement this to insert a new row. As a courtesy, call notifyChange() after inserting. This method can be called from multiple threads, as described in Application Fundamentals: Processes and Threads.

Called by the system when the device configuration changes while your component is running. Note that, unlike activities, other components are never restarted when a configuration changes: they must always deal with the results of the change, such as by re-retrieving resources.

At the time that this function has been called, your Resources object will have been updated to return resource values matching the new configuration.

Called when the provider is being started.

This is called when the overall system is running low on memory, and would like actively running process to try to tighten their belt. While the exact point at which this will be called is not defined, generally it will happen around the time all background process have been killed, that is before reaching the point of killing processes hosting service and foreground UI that we would like to avoid killing.

Applications that want to be nice can implement this method to release any caches or other unnecessary resources they may be holding on to. The system will perform a gc for you after returning from this method.

This is like openFile(Uri, String), but can be implemented by providers that need to be able to return sub-sections of files, often assets inside of their .apk. Note that when implementing this your clients must be able to deal with such files, either directly with ContentResolver.openAssetFileDescriptor, or by using the higher-level ContentResolver.openInputStream or ContentResolver.openOutputStream methods.

Note: if you are implementing this to return a full file, you should create the AssetFileDescriptor with UNKNOWN_LENGTH to be compatible with applications that can not handle sub-sections of files.

Open a file blob associated with a content URI. This method can be called from multiple threads, as described in Application Fundamentals: Processes and Threads.

Returns a ParcelFileDescriptor, from which you can obtain a FileDescriptor for use with FileInputStream, FileOutputStream, etc. This can be used to store large data (such as an image) associated with a particular piece of content.

The returned ParcelFileDescriptor is owned by the caller, so it is their responsibility to close it when done. That is, the implementation of this method should create a new ParcelFileDescriptor for each call.

Receives a query request from a client in a local process, and returns a Cursor. This is called internally by the ContentResolver. This method can be called from multiple threads, as described in Application Fundamentals: Processes and Threads.

Example client call:

// Request a specific record.
 Cursor managedCursor = managedQuery(
                Contacts.People.CONTENT_URI.addId(2),
                projection,    // Which columns to return.
                null,          // WHERE clause.
                People.NAME + " ASC");   // Sort order.

// SQLiteQueryBuilder is a helper class that creates the
        // proper SQL syntax for us.
        SQLiteQueryBuilder qBuilder = new SQLiteQueryBuilder();

        // Set the table we're querying.
        qBuilder.setTables(DATABASE_TABLE_NAME);

        // If the query ends in a specific record number, we're
        // being asked for a specific record, so set the
        // WHERE clause in our query.
        if((URI_MATCHER.match(uri)) == SPECIFIC_MESSAGE){
            qBuilder.appendWhere("_id=" + uri.getPathLeafId());
        }

        // Make the query.
        Cursor c = qBuilder.query(mDb,
                projection,
                selection,
                selectionArgs,
                groupBy,
                having,
                sortOrder);
        c.setNotificationUri(getContext().getContentResolver(), uri);
        return c;

Update a content URI. All rows matching the optionally provided selection will have their columns listed as the keys in the values map with the values of those keys. As a courtesy, call notifyChange() after updating. This method can be called from multiple threads, as described in Application Fundamentals: Processes and Threads.

Returns true if this instance is a temporary content provider.

Convenience for subclasses that wish to implement openFile(Uri, String) by looking up a column named "_data" at the given URI.

Change the permission required to read data from the content provider. This is normally set for you from its manifest information when the provider is first created.

Change the permission required to read and write data in the content provider. This is normally set for you from its manifest information when the provider is first created.