I am getting this error "The instance member 'setState' cant be accessed in an initializer" here :

This is the full code :

class insertLossEvent extends StatefulWidget {
  @override
  State<insertLossEvent> createState() => _insertLossEventState();
}

class _insertLossEventState extends State<insertLossEvent> {
  static final field_1Controller = TextEditingController();
  static final field_4Controller = TextEditingController();

  void _sendLogin() async {
    var newMessage = await (ReadCache.getString(key: 'cache1'));

    var map = <String, dynamic>{
      "Field_1": field_1Controller.text,
      "Field_4": field_4Controller.text,
      "table_id": "25510",
      "form_type": "2",
    };

    var res = await http.post(
      Uri.parse("http://192.168.1.4:8080/HongLeong/SET_FORM_REQUEST.do"),
      headers: {HttpHeaders.cookieHeader: newMessage},
      body: map,
    );

    final data = jsonDecode(res.body);
    print(data);
  }

  int _selectedIndex = 0;

  void _navigateBottomBar(int index) {
    setState(() {
      _selectedIndex = index;
    });
  }


  static List<String> orgUnit = [
    'M1',
    'M100138',
    'M100078',
    'M100108',
    'M100069',
    'M100118',
    'M100071',
    'M100150'
  ];
  
  static String valueChoose;

  final List<Widget> _pages = [
    Container(
      child: SingleChildScrollView(
        child: Column(
          children: [
            //Main Info
            ListTileTheme(
              tileColor: Colors.grey,
              child: ExpansionTile(
                title: Text('Main Info',
                    style: GoogleFonts.poppins(
                        textStyle: const TextStyle(
                      color: Colors.black,
                      fontWeight: FontWeight.bold,
                      fontSize: 20,
                    ))),
                children: [
                  //Fields
                  ListTileTheme(
                    tileColor: Colors.white,
                    child: ListTile(
                      title: Text(
                        'Title : ',
                        style: GoogleFonts.poppins(
                          textStyle: const TextStyle(
                            fontWeight: FontWeight.bold,
                            fontSize: 20,
                          ),
                        ),
                      ),
                    ),
                  ),
                  ListTileTheme(
                    tileColor: Colors.white,
                    child: ListTile(
                      title: Container(
                        decoration: BoxDecoration(
                          color: Colors.transparent,
                          border: Border.all(color: Colors.blueGrey),
                          borderRadius: BorderRadius.circular(10),
                        ),
                        child: Padding(
                          padding: const EdgeInsets.all(8.0),
                          child: TextField(
                            decoration: InputDecoration(
                                border: InputBorder.none,
                            ),
                            controller: field_1Controller,
                            style: GoogleFonts.poppins(
                              textStyle: const TextStyle(
                                fontWeight: FontWeight.normal,
                                fontSize: 20,
                              ),
                            ),
                          ),
                        ),
                      ),
                    ),
                  ),
                  ListTileTheme(
                    tileColor: Colors.white,
                    child: ListTile(
                      title: Text(
                        'Organization Unit : ',
                        style: GoogleFonts.poppins(
                          textStyle: const TextStyle(
                            fontWeight: FontWeight.bold,
                            fontSize: 20,
                          ),
                        ),
                      ),
                    ),
                  ),
                  ListTileTheme(
                    tileColor: Colors.white,
                    child: ListTile(
                      title: Container(
                        decoration: BoxDecoration(
                          color: Colors.transparent,
                          border: Border.all(color: Colors.blueGrey),
                          borderRadius: BorderRadius.circular(10),
                        ),
                        child: Padding(
                          padding: const EdgeInsets.all(8.0),
                          child: DropdownButton<String>(
                            value: valueChoose,
                            onChanged: (newValue){
                              setState(() {
                                valueChoose = newValue;
                              });
                            },
                            items: orgUnit.map((valueItem) {
                              return DropdownMenuItem(
                                value: valueItem,
                                child: Text(valueItem),
                              );
                            }).toList(),
                        ),
                      ),
                    ),
                  ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    ),
    Container(
      child: SingleChildScrollView(
        child: Column(
          children: [
            //Shariah Details
            ListTileTheme(
              tileColor: Colors.grey,
              child: ExpansionTile(
                title: Text('Shariah Details',
                    style: GoogleFonts.poppins(
                        textStyle: const TextStyle(
                      color: Colors.black,
                      fontWeight: FontWeight.bold,
                      fontSize: 20,
                    ))),
                children: [
                  //Fields
                ],
              ),
            ),
          ],
        ),
      ),
    )
  ];

In the best case scenario, I'd like to retain the code as this, but if you know of any improvements, please let me know. How can I make it better? & what causes it to take place? Thank You

CodePudding user response：

Define pages like

 List<Widget> _pages = [];

Then in initstate add values to it

_pages = [// add values here
 ];
 setState((){});

The issue is that you tried adding set state when the codes are initialising. Adding it in initatate will not theow this error

CodePudding user response：

Using late keyword will fix this issue like

late final List<Widget> _pages = [

But I will suggest to use method instead of variables in this case. Using variable doesn't get update context until you reassign the variable.

Do like this is better

  List<Widget> _pages(BuildContext context) => [

CodePudding user response：

to solve the problem, just add the pages List in the build Function and add return Container();

@override
Widget build(BuildContext context) {
    final List<Widget> _pages = [
       ....
    ];
    return Container();
}