Fixed a bug in SQLiteDatabase#query(). (Fixes #4)

Author: artob

CHANGELOG.md

@@ -7,7 +7,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [0.4.3] - 2019-03-13
-### Added
+### Changed
+- Fixed a bug in `SQLiteDatabase#query()`
+  ([#4](https://github.com/drydart/flutter_sqlcipher/issues/4))
 
 ## [0.4.2] - 2019-03-13
 ### Changed

lib/src/database.dart

@@ -429,7 +429,7 @@ abstract class SQLiteDatabase implements SQLiteClosable {
       'groupBy': groupBy,
       'having': having,
       'orderBy': orderBy,
-      'limit': limit.toString(),
+      'limit': limit?.toString(),
     };
     final List<dynamic> result = await _channel.invokeMethod('query', request);
     assert(result.length == 2);