当用户点击 BottomNavigationBarItem 时如何显示 flutter modalBottomSheet

Question

I would like to display a modalBottomsheet when user taps a BottomNavigationBarItem, i tried to put the code in a function and call it in the body of a scaffold but that did not work.. any ideas on how to do this? see my code below

import 'package:flutter/material.dart';
import 'package:modal_bottom_sheet/modal_bottom_sheet.dart';

class More extends StatefulWidget {
  More({Key key}) : super(key: key);

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

class _MoreState extends State<More> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text(
            'Modal Bottom Sheet',
            style: TextStyle(color: Colors.white),
          ),
          centerTitle: true,
        ),
        body: displayModal());
  }

  displayModal() {
    showBottomSheet(
      context: context,
      builder: (context) => Container(child: Text("data")),
    );
  }
}

Answer 1

showBottomSheet is a async function. you should use something like this

 body: Center(
          child: ElevatedButton(
            onPressed: () {
              displayModal();
            },
            child: Text("show dialog"),
          ),
        )

if you want to show the dialog on widget load, call the dialog in initState of the statefull widget

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) async {
      displayModal();
    });
  }