no_logic_in_create_state

Don’t put any logic in createState.

This rule is available as of Dart 2.8.1.

Rule sets: flutter

Details

DON’T put any logic in createState().

Implementations of createState() should return a new instance of a State object and do nothing more. Since state access is preferred via the widget field, passing data to State objects using custom constructor parameters should also be avoided and so further, the State constructor is required to be passed no arguments.

BAD:

MyState global;

class MyStateful extends StatefulWidget {
  @override
  MyState createState() {
    global = MyState();
    return global;
  } 
}

class MyStateful extends StatefulWidget {
  @override
  MyState createState() => MyState()..field = 42;
}

class MyStateful extends StatefulWidget {
  @override
  MyState createState() => MyState(42);
}

GOOD:

class MyStateful extends StatefulWidget {
  @override
  MyState createState() {
    return MyState();
  }
}

Usage

To enable the no_logic_in_create_state rule, add no_logic_in_create_state under linter > rules in your analysis_options.yaml file:

linter:
  rules:
    - no_logic_in_create_state