flutter - 类型 'Null' 不是类型转换中类型 'Map' 的子类型

Question

当我想创建包含多个页面的动态导航时出现此错误。这是下面的代码..

import 'package:flutter/material.dart';
import 'screens/locations/locations.dart';
import 'screens/location_detail.dart';

 const LocationsRoute = "/";
 const LocationDetailRout = '/location_detail';

 class App extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
   return MaterialApp(
    onGenerateRoute: _routes(),
);

 RouteFactory _routes() {
   return (settings) {
   // final Map<String, dynamic> arguments = settings.arguments;
    final arguments = settings.arguments as Map<String, dynamic>;
    Widget screen;
    switch (settings.name) {
      case LocationsRoute:
      screen = Locations();
      break;
      case LocationDetailRout:
      screen = LocationDetail(arguments['id']);
  }
};

Answer 1

快速修复

Map arguments = (settings.arguments??{}) as Map;