json - 将json数据发送到新屏幕Flutter

Question

我想将json对象发送到新的dart文件并在其中使用它。
在第一个文件中是一个列表 View ，当您点击列表项时，将调用secondscreen(jobdetail)，并通过该调用将所有json信息发送到secondscreen(jobdetail)并将其打印到控制台中。
如果您有其他更好的方法，则不必纠正我的方法。
这是我尝试的方式:
第一个画面:

onTap: () {
              Navigator.push(
                context,
                MaterialPageRoute(
                  builder: (context) => JobDetail(),
                  // Pass the arguments as part of the RouteSettings. The
                  // DetailScreen reads the arguments from these settings.
                  settings: RouteSettings(
                    arguments: jsonData[index],
                  ),
                ),
              );
            },

第二屏(jobdetail):

class JobDetail extends StatelessWidget {

@override
Widget build(BuildContext context) {
final jsonData = ModalRoute.of(context).settings.arguments;
print(jsonData.titel);
return new MaterialApp(
  debugShowCheckedModeBanner: false,
  title: 'Flutter App with MYSQL',
  home: new MyHomePage(),

);
}
}

Future<dynamic> senddata() async {
final response = await http.post(
  "https://www.quyre.de/2/JobBlock.N.php", body: {
"status": "0",
"Id": "5",
"JobBlocksInProres": "0",
"IdJB": jsonData.titel,
});

var datauser = json.decode(response.body);

String jsonsDataString = datauser.toString();
dynamic Data = jsonDecode(jsonsDataString);

print(Data);


return Data;
}

我收到此错误:

lib/JobDetail.dart:15:20: Error: The getter 'titel' isn't defined for the class 'Object'.
 - 'Object' is from 'dart:core'.
Try correcting the name to the name of an existing getter, or defining a getter or field     named 'titel'.
print(jsonData.titel);
               ^^^^^
lib/JobDetail.dart:31:13: Error: Getter not found: 'jsonData'.
"IdJB": jsonData.id,
        ^^^^^^^^
lib/JobDetail.dart:37:11: Error: Can't declare 'jsonData' because it was already used in this scope.
  dynamic jsonData = jsonDecode(jsonsDataString);
      ^^^^^^^^
lib/JobDetail.dart:31:13: Context: Previous use of 'jsonData'.
"IdJB": jsonData.id,
        ^^^^^^^^
lib/JobDetail.dart:39:9: Error: Getter not found: 'jsonData'.
  print(jsonData);
    ^^^^^^^^
lib/JobDetail.dart:42:10: Error: Getter not found: 'jsonData'.
  return jsonData;

谢谢你的回答
新代码
第一个画面:

onTap: () {
              JobDetailScreenArg arg = JobDetailScreenArg(jsonData);
              Navigator.of(context).pushNamed('/JobDetailScreen', arguments: arg);
            },

其余的也在文件中
第二屏:

  import 'package:flutter/material.dart';

import 'package:navigation/Muensterboerse.dart';

class JobDetailScreen extends StatefulWidget {
final Job job;

JobDetailScreen(this.job);

@override
_JobDetailScreenState createState() => _JobDetailScreenState();
}

class _JobDetailScreenState extends State<JobDetailScreen> {
 @override
 Widget build(BuildContext context) {
     return Container(
     child: Text('${job.title}'),
   );
 }
}

Answer 1

首先，请检查以下内容:

在第一个屏幕上，我觉得jsonData被解码为dynamic类型。如果您的jsonString是有效的JSON，请将其解码为Map<String, dynamic>。例如Map<String, dynamic> data = jsonDecode(jsonString)。注意FormatException & TypeError。

另外，如果您的jsonString包含项列表(作业json对象)，则按如下所示转换列表并将其项映射到您自己的Dart对象中。

var items = data['jobs'] as List;
List<Job> jobs = items.map<Job>((jobItem) => Job.fromJSON(jobItem)).toList();

您的Job Dart对象可能如下所示

class Job {
  final String title;
  // Other properties

  Job({this.title});

  factory Job.fromJSON(Map<String, dynamic> map) {
    return Job(
      title: map['title'],
    );
  }
}

接下来，我建议使用下面的代码片段作为从途中向另一个发送数据的好方法。

首选命名路线
About named routes

为您的路由参数数据创建参数类

class JobDetailScreenArg {
  final Job job;

  JobDetailScreenArg(this.job);
}

MaterialApp(
    title: 'Jobs',
    // Start the app with the "/" named route. In this case, the app starts
    // on the FirstScreen widget.
    initialRoute: '/',
    onGenerateRoute: (RouteSettings settings) {
      switch(settings.name) {
        case '/jobDetail':
         JobDetailScreenArg args = settings.arguments;
         return _buildRoute(settings, JobDetailScreen(args.job));
        case '/':
         return _buildRoute(settings, JobsScreen());
      }
    }
  )



Route _buildRoute(RouteSettings settings, Widget screen) {
    return MaterialPageRoute(
      settings: settings,
      builder: (context) => screen,
    );
  }

职位列表屏幕

onTap: () {
  // job - tapped item
  JobDetailScreenArg arg = JobDetailScreenArg(job);
  Navigator.of(context).pushNamed('/jobDetail', arguments: arg);
}

详细信息屏幕

class JobDetailScreen extends StatefulWidget {
  final Job job;
  
  JobDetailScreen(this.job);

  @override
  _JobDetailScreenState createState() => _JobDetailScreenState();
}

class _JobDetailScreenState extends State<JobDetailScreen> {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Text('${job.title}'),
    );
  }
}