setState вызывается во время сборки во флаттере

Хорошие новости : это не ваша вина.

Плохие новости : вам нужно изменить их код или подождать, пока они его изменят.

Я создал запрос на перенос на github, здесь. Однако они, похоже, не реагируют на проблемы, поэтому вам может быть лучше изменить их код.

Итак, если вы хотите использовать этот пакет, вам следует изменить код внутри lite_rolling_switch.dart (либо перейдя в ~ / .pub-cache / hosted / pub.dartlang.org / lite_rolling_switch-0.1.1. /lib/lite_rolling_switch.dart или вы можете Ctrl + щелчок левой кнопкой мыши по классу LiteRollingSwitch в вашем файле) на следующее:

library lite_rolling_switch;

import 'package:flutter/material.dart';
import 'dart:ui';
import 'dart:math';

/// Customable and attractive Switch button.
/// Currently, you can't change the widget
/// width and height properties.
///
/// As well as the classical Switch Widget
/// from flutter material, the following
/// arguments are required:
///
/// * [value] determines whether this switch is on or off.
/// * [onChanged] is called when the user toggles the switch on or off.
///
/// If you don't set these arguments you would
/// experiment errors related to animationController
/// states or any other undesirable behavior, please
/// don't forget to set them.
///
class LiteRollingSwitch extends StatefulWidget {
  @required
  final bool value;
  @required
  final Function(bool) onChanged;
  final String textOff;
  final String textOn;
  final Color colorOn;
  final Color colorOff;
  final double textSize;
  final Duration animationDuration;
  final IconData iconOn;
  final IconData iconOff;
  final Function onTap;
  final Function onDoubleTap;
  final Function onSwipe;

  LiteRollingSwitch(
      {this.value = false,
      this.textOff = "Off",
      this.textOn = "On",
      this.textSize = 14.0,
      this.colorOn = Colors.green,
      this.colorOff = Colors.red,
      this.iconOff = Icons.flag,
      this.iconOn = Icons.check,
      this.animationDuration = const Duration(milliseconds: 600),
      this.onTap,
      this.onDoubleTap,
      this.onSwipe,
      this.onChanged});

  @override
  _RollingSwitchState createState() => _RollingSwitchState();
}

class _RollingSwitchState extends State<LiteRollingSwitch>
    with SingleTickerProviderStateMixin {
  AnimationController animationController;
  Animation<double> animation;
  double value = 0.0;

  bool turnState;

  @override
  void dispose() {
    animationController.dispose();
    super.dispose();
  }

  @override
  void initState() {
    super.initState();
    animationController = AnimationController(
        vsync: this,
        lowerBound: 0.0,
        upperBound: 1.0,
        duration: widget.animationDuration);
    animation =
        CurvedAnimation(parent: animationController, curve: Curves.easeInOut);
    animationController.addListener(() {
      setState(() {
        value = animation.value;
      });
    });
    turnState = widget.value;
    if (turnState) {
      animationController.animateTo(1, duration: Duration(seconds: 0));
    }
  }

  @override
  Widget build(BuildContext context) {
    Color transitionColor = Color.lerp(widget.colorOff, widget.colorOn, value);

    return GestureDetector(
      onDoubleTap: () {
        _action();
        if (widget.onDoubleTap != null) widget.onDoubleTap();
      },
      onTap: () {
        _action();
        if (widget.onTap != null) widget.onTap();
      },
      onPanEnd: (details) {
        _action();
        if (widget.onSwipe != null) widget.onSwipe();
        //widget.onSwipe();
      },
      child: Container(
        padding: EdgeInsets.all(5),
        width: 130,
        decoration: BoxDecoration(
            color: transitionColor, borderRadius: BorderRadius.circular(50)),
        child: Stack(
          children: <Widget>[
            Transform.translate(
              offset: Offset(10 * value, 0), //original
              child: Opacity(
                opacity: (1 - value).clamp(0.0, 1.0),
                child: Container(
                  padding: EdgeInsets.only(right: 10),
                  alignment: Alignment.centerRight,
                  height: 40,
                  child: Text(
                    widget.textOff,
                    style: TextStyle(
                        color: Colors.white,
                        fontWeight: FontWeight.bold,
                        fontSize: widget.textSize),
                  ),
                ),
              ),
            ),
            Transform.translate(
              offset: Offset(10 * (1 - value), 0), //original
              child: Opacity(
                opacity: value.clamp(0.0, 1.0),
                child: Container(
                  padding: EdgeInsets.only(/*top: 10,*/ left: 5),
                  alignment: Alignment.centerLeft,
                  height: 40,
                  child: Text(
                    widget.textOn,
                    style: TextStyle(
                        color: Colors.white,
                        fontWeight: FontWeight.bold,
                        fontSize: widget.textSize),
                  ),
                ),
              ),
            ),
            Transform.translate(
              offset: Offset(80 * value, 0),
              child: Transform.rotate(
                angle: lerpDouble(0, 2 * pi, value),
                child: Container(
                  height: 40,
                  width: 40,
                  alignment: Alignment.center,
                  decoration: BoxDecoration(
                      shape: BoxShape.circle, color: Colors.white),
                  child: Stack(
                    children: <Widget>[
                      Center(
                        child: Opacity(
                          opacity: (1 - value).clamp(0.0, 1.0),
                          child: Icon(
                            widget.iconOff,
                            size: 25,
                            color: transitionColor,
                          ),
                        ),
                      ),
                      Center(
                          child: Opacity(
                              opacity: value.clamp(0.0, 1.0),
                              child: Icon(
                                widget.iconOn,
                                size: 21,
                                color: transitionColor,
                              ))),
                    ],
                  ),
                ),
              ),
            )
          ],
        ),
      ),
    );
  }

  _action() {
    _determine(changeState: true);
  }

  _determine({bool changeState = false}) {
    setState(() {
      if (changeState) turnState = !turnState;
      (turnState)
          ? animationController.forward()
          : animationController.reverse();

      widget.onChanged(turnState);
    });
  }
}