query

open fun query(uri: Uri, projection: Array<String>, selection: String, selectionArgs: Array<String>, sortOrder: String): Cursor

Implement this to handle query requests from clients. 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 (
   ContentUris.withAppendedId (Contacts.People.CONTENT_URI, 2),
   projection, // Which columns to return.
   null, // WHERE clause.
   null, // WHERE clause value substitution
   People.NAME + " ASC"); // Sort order.
Example implementation:
// 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;

Return

a Cursor or null.

Parameters

uri

The URI to query. This will be the full URI sent by the client; if the client is requesting a specific record, the URI will end in a record number that the implementation should parse and add to a WHERE or HAVING clause, specifying that _id value.

projection

The list of columns to put into the cursor. If null all columns are included.

selection

A selection criteria to apply when filtering rows. If null then all rows are included.

selectionArgs

You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. The values will be bound as Strings.

sortOrder

How the rows in the cursor should be sorted. If null then the provider is free to define the sort order.