Showmodalbuttom sheet 'Invalid constant value'

Question


    import 'package:flutter/material.dart';
    import 'package:todoey/screen/tasks_list.dart';

    class TasksScreen extends StatelessWidget {
      
      Widget buildButtomSheet(BuildContext context) {
        return Container();
      }
      @override
      Widget build(BuildContext context) {
        return Scaffold(
          backgroundColor: Colors.lightBlueAccent,
          floatingActionButton:  FloatingActionButton(
            backgroundColor: Colors.lightBlueAccent,
            child: const Icon(Icons.add),
            onPressed: () {
             showModalBottomSheet = showModalBottomSheet(context: context, builder: buildButtomSheet);
        },
          ),
          body: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: <Widget>[
              Container(
                padding: const EdgeInsets.only(
                    top: 60.0, left: 30, right: 30, bottom: 30.0),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: const <Widget>[
                    CircleAvatar(
                      child: Icon(
                        Icons.list,
                        size: 30,
                        color: Colors.lightBlueAccent,
                      ),
                      backgroundColor: Colors.white,
                      radius: 30,
                    ),
                    SizedBox(height: 10),
                    Text(
                      'Todoey',
                      style: TextStyle(
                        color: Colors.white,
                        fontSize: 50,
                        fontWeight: FontWeight.w700,
                      ),
                    ),
                    Text(
                      '12 task',
                      style: TextStyle(
                        color: Colors.white,
                      ),
                    ),
                  ],
                ),
              ),
              Expanded(
                child: Container(
                  padding: const EdgeInsets.symmetric(horizontal: 20),
                  decoration: const BoxDecoration(
                    borderRadius: BorderRadius.only(
                        topLeft: Radius.circular(30.0),
                        topRight: Radius.circular(30)),
                    color: Colors.white,
                  ),
                  child: const TasksList(),
                ),
              ),
            ],
          ),
        );
      }
    }

   child: const Icon(Icons.add),
            onPressed: () {
             showModalBottomSheet = showModalBottomSheet(context: context, builder: buildButtomSheet);

I had issues with the code line above, i have tried several changes but it still tells "Invalid function".

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Md. Yeasin Sheikh · Answer 1 · 2022-09-18T17:23:01.993

0

Remove const from FloatingActionButton, because onPressed method will be called on run time.

floatingActionButton: FloatingActionButton(
  onPressed: () {},
),

More about const

floatingActionButton: FloatingActionButton(
  backgroundColor: Colors.lightBlueAccent,
  child: const Icon(Icons.add),
  onPressed: () async {
    final result = await showModalBottomSheet(
        context: context, builder: buildButtomSheet);
  },
),

edited Sep 18 '22 at 17:23

answered Sep 18 '22 at 03:49

Md. Yeasin Sheikh

54,221
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Thanks, removed const as instructed but the code is requesting I add an identifier on line 16. – Jamiekazi Sep 18 '22 at 06:02
I suspect it is line 15, try `child: const Icon(Icons.add),` also consider including code-snippet instead of code-image. – Md. Yeasin Sheikh Sep 18 '22 at 06:06
I got the same error after the changes. – Jamiekazi Sep 18 '22 at 16:53
Can you include minimal code-snippet instead of code image that will reproduce the error. Consider following question comment links. – Md. Yeasin Sheikh Sep 18 '22 at 16:54
I have tried the changes in line 15, but the error is still reflected in the code. – Jamiekazi Sep 18 '22 at 17:14
Could be different issue, I will try to rename to fetch data , try update one – Md. Yeasin Sheikh Sep 18 '22 at 17:23
Eureka!!! it worked, thank you very much. I can now see my showModalbuttom sheet. Please can you explain a little bit of the changes you made. Thanks. – Jamiekazi Sep 19 '22 at 03:49
`showModalBottomSheet` is a future method, need to `await` to fetch data. and you need to use a variable to get data from it. while `showModalBottomSheet` can be conflict, while reading separate variable is more readable . – Md. Yeasin Sheikh Sep 19 '22 at 04:52

Showmodalbuttom sheet 'Invalid constant value'

1 Answers1