Flutter AnimatedOpacity() でDurationをかけよう！！

2020年3月1日2023年7月26日

ほとんどAnimatedContainer使用したOpacityと同じですが

念のため、AnimatedContainerはこちらから

AnimatedOpacity コードの全容

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Animate(),
    );
  }
}

class Animate extends StatefulWidget {
  @override
  _AnimateState createState() => _AnimateState();
}

class _AnimateState extends State<Animate> {
  bool check = false;
  double opacity = 1.0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Opacty'),
      ),
      body: AnimatedOpacity(
        duration: Duration(seconds: 2),
          opacity: check ? opacity = 0.0 : opacity = 1.0,
          child: Image.asset("tutenkaku.jpg"),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () => setState(() {
          check ? check = false : check = true;
        }),
      ),
    );
  }
}