flutter - 错误 : The argument type 'MaterialPageRoute' can't be assigned to the parameter type 'Route<Map>'

Question

我正在学习 flutter，这段代码直接来自老师。我知道 flutter 一直在变化，这可能就是它没有运行的原因。不管怎样，它是:

class Klimatic extends StatefulWidget {
  @override
  _KlimaticState createState() => new _KlimaticState();
}

class _KlimaticState extends State<Klimatic> {

  String _cityEntered;

  Future _goToNextScreen(BuildContext context) async {
    Map results = await Navigator
        .of(context)
        .push(new MaterialPageRoute<dynamic>(builder: (BuildContext context) {
      return new ChangeCity();
    }));

    if ( results != null && results.containsKey('enter')) {
       _cityEntered = results['enter'];

//      debugPrint("From First screen" + results['enter'].toString());


    }
  }

Answer 1

在不了解确切的 API 详细信息的情况下，看起来您期待的是一种类型 Route<Map> , 但你正在创建一个 Route<dynamic> (或 MaterialPageRoute<dynamic> )。我假设您可以尝试:

new MaterialPageRoute<Map>(...)

... 相反。