If I use StatefulWidget in StatelessWidget, each StatefulWidget perform like Stateless Widget?-CodePudding

I use Widgets Like this (image). How performed they are?

enter image description here

CodePudding user response：

A Stateful widget will perform exactly like a Stateless widget unless you mutate the state using setState method. The only time UI is rebuilt is when your run the setState((){}) method inside the Stateful widget.

Sample setState example from documentation.

class Bird extends StatefulWidget {
  const Bird({
    Key? key,
    this.color = const Color(0xFFFFE306),
    this.child,
  }) : super(key: key);

  final Color color;
  final Widget? child;

  @override
  State<Bird> createState() => _BirdState();
}

class _BirdState extends State<Bird> {
  double _size = 1.0;

  void grow() {
    setState(() { _size  = 0.1; });
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      color: widget.color,
      transform: Matrix4.diagonal3Values(_size, _size, 1.0),
      child: widget.child,
    );
  }
}

Reference: Stateful Widgets - LINK

You can try and learn about Stateful widgets in the above documentation link.