flutter开发警告This class (or a class that this class inherits from) is marked as ‘@immutable‘, but one

Problem Description

This class (or a class that this class inherits from) is marked as ‘@immutable’, but one or more of its instance fields aren’t final: SerialsTimer.tasks

problem code

class SerialsTimer extends StatefulWidget {
    
    
  late Queue <Task> tasks; // 使用 Queue 来管理任务

  SerialsTimer({
    
    
    Key? key,
    required this.tasks,
  }) : super(key: key);

  @override
  State<SerialsTimer> createState() => _SerialsTimerState();
}

problem causes

Dart infers that the class you wrote is an @immutable (immutable) class.
This warning is because in a class marked as @immutable (immutable), one of the instance fields (member variables) is not declared as final.

In Dart, if you use the @immutable annotation, it requires that all instance fields of the class should be final to ensure the immutability of the object. The creation and management of immutable objects helps write more reliable and maintainable code.

How to solve

To resolve this warning, you can mark instance fields as final when declaring them.

Added final modifier to fix tasks field in SerialsTimer class. In this way, the class meets the requirements of @immutable. Please make sure to comply with the regulations in other fields as well.

Modified source code

class SerialsTimer extends StatefulWidget {
    
    
  final Queue <Task> tasks; // 使用 Queue 来管理任务

  const SerialsTimer({
    
    
    Key? key,
    required this.tasks,
  }) : super(key: key);

  @override
  State<SerialsTimer> createState() => _SerialsTimerState();
}

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