flutter - AlertDialog 函数在 flutter 的每个页面上运行

Question

此代码中的 AlertDialog 应该仅在用户访问帐户页面时运行(很明显)，但在测试它时，它会在帐户页面和所有下一页上运行，甚至重复，我的意思是当我从Account页面到另一个页面AlertDialog会显示两次

    class Account extends StatefulWidget {
    @override
      _AccountState createState() => _AccountState();
}

class _AccountState extends State<Account> {
  @override
  Widget build(BuildContext context) {
    Future.delayed(Duration.zero, () => FirstRun(context));
    return Scaffold(
    //there are alot of widgets here like drawer but all of it works fine
    //i don't think its necessary to write it
    );
  }
FirstRun(BuildContext context) async {
SharedPreferences prefs = await SharedPreferences.getInstance();
bool first = (prefs.getBool('firstUse'));
print('Pressed $first');
if (first == null) {
  showDialog(
    context: context,
    builder: (BuildContext context) {
      return AlertDialog(
        backgroundColor: Color(0xaa6b6b6b),
        elevation: 10,
        content: Column(
          mainAxisSize: MainAxisSize.min,
          children: <Widget>[
            Text(
              'first run dialog',
              overflow: TextOverflow.ellipsis,
              maxLines: 6,
              style: TextStyle(
                color: Colors.white,
                fontSize: 24,
              ),
              textAlign: TextAlign.center,
            ),
            Container(
                child: MaterialButton(
                  onPressed: () {
                    prefs.setBool('firstUse', false);
                    Navigator.of(context).pop();
                    print('Pressed $first');
                  },
                  child: Text(
                    'ok',
                      ),
                    ))
              ],
            ),
          );
        },
      );
    }
  }
}

Answer 1

可能是因为您开始在 build 方法上显示警报。尝试在 Account 小部件的 initState 方法上显示它。

class _AccountState extends State<Account> {
  @override
  initState() {
     Future.delayed(Duration.zero, () => FirstRun(this.context));
     super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
    //there are alot of widgets here like drawer but all of it works fine
    //i don't think its necessary to write it
    );
  }