Flutter use one Variable in different classes Error: Getter not found: 'allJobs'

I have a Variable in one Class but and i want to use it in all. In this Example is the allJobs Variable which is declared in Muesnterboerse ore MuensterboerseAAAngebote and i want to use it in senddate().

class Muensterboerse extends StatelessWidget {
var allJobs = 1;

@override
Widget build(BuildContext context) {
return new MaterialApp(
  debugShowCheckedModeBanner: false,
  title: 'Flutter App with MYSQL',
  home: new MyHomePage(),

);
}
}

class MuensterboerseAAAngebote extends StatelessWidget {
var allJobs = 0;

@override
Widget build(BuildContext context) {
return new MaterialApp(
  debugShowCheckedModeBanner: false,
  title: 'Flutter App with MYSQL',
  home: new MyHomePage(),

);
}
}

Future<dynamic> senddata() async {
final response = await http.post(
  "https://www.bumsbirnbe.php", body: {
"status": allJobs,
});



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

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

print(jsonData);


return jsonData;
}

Update Now i added your changes to my code but i get the

Error: Unhandled Exception: NoSuchMethodError: The getter 'allJobs' was called on null.

This is my whole code:

import 'dart:async';
import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;

GlobalKey _key1 = GlobalKey();

class Muensterboerse extends StatelessWidget {
  Muensterboerse({Key key}) : super(key: key);

  int allJobs = 1;

  @override
  Widget build(BuildContext context) {
  return new MaterialApp(
  debugShowCheckedModeBanner: false,
  title: 'Flutter App with MYSQL',
  home: new MyHomePage(),

  );
  }
  }

class AAAngebote extends StatelessWidget {
  AAAngebote({Key key}) : super(key: key);

  int allJobs = 2;
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      debugShowCheckedModeBanner: false,
  title: 'Flutter App with MYSQL',
  home: new MyHomePage(),

    );
  }
}

Future<dynamic> senddata() async {
  int allJobs = (_key1.currentWidget as Muensterboerse).allJobs;
  print(allJobs);

  final response = await http.post(
      "https://www.Bumsbirne.php", body: {
    "status": allJobs,
  });


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

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

  print(jsonData);


  return jsonData;
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

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


class _MyHomePageState extends State<MyHomePage> {
  dynamic jsonData;


  callSendData() async {
      jsonData = await senddata();
      setState(() {});
  }

//lol
  @override
  void initState() {
    callSendData();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: jsonData == null
            ? Center(child: CircularProgressIndicator())
            : ListView.builder(
           padding: const EdgeInsets.all(16.0),
            itemCount: jsonData == null ? 0 : jsonData.length,
            itemBuilder: (context, index) {
              return ListTile(

                leading: CircleAvatar(
                  backgroundImage:     NetworkImage('https://kinsta.com/de/wpcontent/uploads/sites/5/2019/09/wordpress-loggst-url-1024x512.jpg'),
                  radius: 27,
            ),

            title: Text(
              jsonData[index]["titel"],
            ),
            subtitle: Text(jsonData[index]["nam_ersteller"]),
            trailing: Text(
              '25 Km',
              style: TextStyle(color: Colors.grey,
                fontSize: 12,
                decoration: TextDecoration.none,
                fontFamily: 'Roboto',),

            ),
            onTap: () {
              Navigator.push(context,
                  new MaterialPageRoute(builder: (context) =>         DetailPage()));
            },

          );
          // return _buildRow(data[index]);
        }));
  }
}

class DetailPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
return Scaffold(
  appBar: AppBar(
    title: Text('Der Job'),
  ),
);
  }
}