AnimationControllerを使った直線的なアニメーションの実装

import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';

void main() {
  runApp(MaterialApp(home: const ScheduleBindingScreen()));
}

class ScheduleBindingScreen extends StatefulWidget {
  const ScheduleBindingScreen({super.key});

  @override
  State<ScheduleBindingScreen> createState() => _ScheduleBindingScreenState();
}

class _ScheduleBindingScreenState extends State<ScheduleBindingScreen> with SingleTickerProviderStateMixin {

  double angle = 0.0;
  late final AnimationController controller;
  @override
  void initState() {
    super.initState();
    controller = AnimationController(vsync: this, duration: Duration(seconds: 1))..addListener(() {setState(() {angle += 0.1;});});
  }

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

  void _start() {
    controller.forward();
  }

  void _reverse() {
    controller.reverse();
  }


  @override
  Widget build(BuildContext context) {

    final screen = Scaffold(
      appBar: AppBar(title: Text('ScheduleBindingTets'),),
      body: SafeArea(child: Center(child: Transform.rotate(angle: angle, child: Container(width: 100, height: 100, color: Colors.blue,),),),),
      floatingActionButton: FloatingActionButton(onPressed: () {
        if(controller.isCompleted) {
          _reverse();
        } else {
          _start();
        }
      },
      child: controller.isCompleted ? Icon(Icons.rotate_left_rounded) : Icon(Icons.play_arrow)
      ),
    );

    return screen;
  }
}