Describe the bug

Error: Unexpected null value.
at Object.throw_ [as throw] (http://localhost:51605/dart_sdk.js:4332:11)
at Object.nullCheck (http://localhost:51605/dart_sdk.js:4662:30)
at page_view.PageController.new.nextPage (http://localhost:51605/packages/flutter/src/widgets/page_view.dart.lib.js:366:38)
at http://localhost:51605/packages/getwidget/components/carousel/gf_carousel.dart.lib.js:1031:38
at http://localhost:51605/dart_sdk.js:23808:9