E/flutter (23361): [ERROR:flutter/shell/common/shell.cc(184)] Dart Error: Unhandled exception:
E/flutter (23361): Failed assertion: boolean expression must not be null
E/flutter (23361): #0      _ActivityDetailsFetchDataState.build.<anonymous closure>.<anonymous closure>
package:appolicoro/attivita/activitydetails.dart:75
E/flutter (23361): #1      State.setState
package:flutter/…/widgets/framework.dart:1130
E/flutter (23361): #2      _ActivityDetailsFetchDataState.build.<anonymous closure>
package:appolicoro/attivita/activitydetails.dart:74
E/flutter (23361): #3      _RootZone.runUnary (dart:async/zone.dart:1379:54)
E/flutter (23361): #4      _FutureListener.handleValue (dart:async/future_impl.dart:129:18)
E/flutter (23361): #5      Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:642:45)