flutter - 使用 ModalRoute 检索参数时出错

Question

每次我调用 modalroute 以从命名路由中检索参数时，我都会得到 null。

这是代码片段:

Navigator.pushNamed(
           context, 
           VerifyCode.routeName, 
           arguments: {'code': randValue,},
           );

这是我检索参数的地方:

Widget build(BuildContext context) 
{
   //Get the dialog provider to display information
   alertViewModel = Provider.of<AlertViewModel>(context);

   //Retrieve the route argument
   final routeArgs =
           ModalRoute.of(context).settings.arguments as Map<String, int>;

    final securityCode = routeArgs['code']; <-- Error happens here

    print('Code =' + securityCode.toString());
   return Container()

}

我应该从 map 中获取一个整数，但我收到了错误:

 ════════ Exception Caught By widgets library ═══════════════════════════════════
The following NoSuchMethodError was thrown building VerifyCode(dirty, dependencies: [InheritedProvider<AlertViewModel>, _ModalScopeStatus], state: _VerifyCodeState#98992):
The method '[]' was called on null.
Receiver: null
Tried calling: []("code")
When the exception was thrown, this was the stack
#0      Object.noSuchMethod  (dart:core-patch/object_patch.dart:50:5)
#1      _VerifyCodeState.build package:accidentapp/screens/verifycode.dart:42
#2      StatefulElement.build 
package:flutter/…/widgets/framework.dart:4012
#3      ComponentElement.performRebuild package:flutter/…/widgets/framework.dart:3924
#4      Element.rebuild
package:flutter/…/widgets/framework.dart:3721 ═══════════════════════════════════════════════════════════════════

routeArgs 始终为空。我尝试使用类来传递值而不是 map ，但我遇到了同样的错误。不知道我做错了什么。

Answer 1

将设置传递给 MaterialPageRoute

Route<dynamic> generateRoute(RouteSettings settings) {
return MaterialPageRoute(
  builder: (BuildContext context) {
    //some custom code
    return Page();
  },
  settings: settings
);

}