Build failing

[hipoojan]

/opt/hostedtoolcache/flutter/2.5.0-stable/x64/.pub-cache/hosted/pub.dartlang.org/flutter_stories-0.3.0/lib/flutter_stories.dart:174:34: Error: Operator '+' cannot be called on 'int?' because it is potentially null.
setState(() => _currentIdx += 1);
^
/opt/hostedtoolcache/flutter/2.5.0-stable/x64/.pub-cache/hosted/pub.dartlang.org/flutter_stories-0.3.0/lib/flutter_stories.dart:164:8: Context: '_currentIdx' refers to a property so it couldn't be promoted.
See http://dart.dev/go/non-promo-property
int? _currentIdx;
^
/opt/hostedtoolcache/flutter/2.5.0-stable/x64/.pub-cache/hosted/pub.dartlang.org/flutter_stories-0.3.0/lib/flutter_stories.dart:174:34: Error: A value of type 'num' can't be assigned to a variable of type 'int?'.
setState(() => _currentIdx += 1);
^
/opt/hostedtoolcache/flutter/2.5.0-stable/x64/.pub-cache/hosted/pub.dartlang.org/flutter_stories-0.3.0/lib/flutter_stories.dart:189:36: Error: Operator '-' cannot be called on 'int?' because it is potentially null.
setState(() => _currentIdx -= 1);
^
/opt/hostedtoolcache/flutter/2.5.0-stable/x64/.pub-cache/hosted/pub.dartlang.org/flutter_stories-0.3.0/lib/flutter_stories.dart:164:8: Context: '_currentIdx' refers to a property so it couldn't be promoted.
See http://dart.dev/go/non-promo-property
int? _currentIdx;
^
/opt/hostedtoolcache/flutter/2.5.0-stable/x64/.pub-cache/hosted/pub.dartlang.org/flutter_stories-0.3.0/lib/flutter_stories.dart:189:36: Error: A value of type 'num' can't be assigned to a variable of type 'int?'.
setState(() => _currentIdx -= 1);
^

FAILURE: Build failed with an exception.

Flutter version: 2.5.0

I did find a fix, I changed the int? _currentIdx; to late int _currentIdx; as you are clearly initializing the variable in initState method so it won't be null even if the user doesn't provide a startAt as it is initialized to be 0 in the constructor and removed all the unnecessary "!" after _currentIdx just to get rid of the warnings.

[Jagmohanrai]

I have fixed that issue and created a PR you can check it out

[vanelizarov]

Fix landed in 0.3.1