try correcting the name to the name of an existing getter, or defining a getter or field named 'body1'. color ??= theme.of(context).texttheme.body1.color;
Just change body1 to bodyText1 in the following location
C:\src\flutter.pub-cache\hosted\pub.dartlang.org\charts_flutter-0.9.0\lib\src\behaviors\legend\legend_entry_layout
this will solve the issue