Flutter中alert使用

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('BottomNavigationBar Sample'),
      ),
      body: Center(
        child: new ListView(
          children: <Widget>[
            new FlatButton(
              onPressed: _neverSatisfied,
              child: new Text('date picker'),
            ),
          ],
        ),
      ),
    );
  }

  // alert
  Future<void> _neverSatisfied() async {
    return showDialog<void>(
      context: context,
      barrierDismissible: false,
      builder: (BuildContext context) {
        return AlertDialog(
          title: Text('Rewind and remember'),
          content: SingleChildScrollView(
            child: ListBody(
              children: <Widget>[
                Text('You will never be satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
                Text('You\'re like me. I\'m never satisfied.'),
              ],
            ),
          ),
          actions: <Widget>[
            FlatButton(
              child: Text('Regret1'),
              onPressed: () {
                Navigator.of(context).pop();
              },
            ),
            FlatButton(
              child: Text('Regret2'),
              onPressed: () {
                Navigator.of(context).pop();
              },
            ),
          ],
        );
      },
    );
  }
}

结果：

alert