使用 ModalRoute 检索参数时出错

Question

每次调用 modalroute 从命名路由检索参数时，我都会得到 null。

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这是代码片段：

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

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这是我检索参数的地方：

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Widget build(BuildContext context) \n{\n   //Get the dialog provider to display information\n   alertViewModel = Provider.of<AlertViewModel>(context);\n\n   //Retrieve the route argument\n   final routeArgs =\n           ModalRoute.of(context).settings.arguments as Map<String, int>;\n\n    final securityCode = routeArgs[\'code\']; <-- Error happens here\n\n    print(\'Code =\' + securityCode.toString());\n   return Container()\n

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}

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我应该从地图中获取一个整数，但我收到了错误：

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 \xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90 Exception Caught By widgets library \xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\nThe following NoSuchMethodError was thrown building VerifyCode(dirty, dependencies: [InheritedProvider<AlertViewModel>, _ModalScopeStatus], state: _VerifyCodeState#98992):\nThe method \'[]\' was called on null.\nReceiver: null\nTried calling: []("code")\nWhen the exception was thrown, this was the stack\n#0      Object.noSuchMethod  (dart:core-patch/object_patch.dart:50:5)\n#1      _VerifyCodeState.build package:accidentapp/screens/verifycode.dart:42\n#2      StatefulElement.build \npackage:flutter/\xe2\x80\xa6/widgets/framework.dart:4012\n#3      ComponentElement.performRebuild package:flutter/\xe2\x80\xa6/widgets/framework.dart:3924\n#4      Element.rebuild\npackage:flutter/\xe2\x80\xa6/widgets/framework.dart:3721 \xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\xe2\x95\x90\n

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RouteArgs 始终为空。我尝试使用类来传递值而不是地图，但我收到了相同的错误。不确定我做错了什么。

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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
);

}

Answer 2

试试这个方法：-

 String rawJson = '{"code":randValue}';
 Map<String, dynamic> map = jsonDecode(rawJson);

 Navigator.pushNamed(context, VerifyCode.routeName, arguments: map);

使用以下方式接收数据：-

final Map<String, dynamic> map = ModalRoute.of(context).settings.arguments;

您可以使用获取数据

map["code"]