Dropdown | NSTACK INDIA

Table of Contents

Flutter Introduction Installation Hello World Flutter Comments Material App Scaffold AppBar Text Center Container Card Image Raise Button Dropdown

I am not sure how much you understand the dropdown but in order to make multi level dropdown you need to understand the dropdown properly.

Label	Description
hint	This value will be shown when no value is selected.
value	This value will be shown as selected
items	It look for list of DropdownMenuItem widget.
onChanged	It is callback and it being called with the value of DropdownButton

You might have notice I have wrote String 5 times. This depends on the value of DropdownButton. It can be anything and every time we are not going to get string. So, it’s important how to work with generic while using DropdownButton.

One more important thing it’s not mandatory to use value and child text as same. Let’s see one more example to understand this.

screens/dropdown.dart

import 'package:flutter/material.dart';

class DropdownScreenDemo extends StatefulWidget {
  @override
  _DropdownScreenDemoState createState() => _DropdownScreenDemoState();
}

class _DropdownScreenDemoState extends State<DropdownScreenDemo> {
  String selectedCountry;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Example 1'),
      ),
      body: Center(
        child: DropdownButton<String>(
          hint: Text('Country'),
          value: selectedCountry,
          items: <DropdownMenuItem<String>>[
            DropdownMenuItem<String>(
              value: 'USA',
              child: Text('USA'),
            ),
            DropdownMenuItem<String>(
              value: 'India',
              child: Text('India'),
            ),
          ],
          onChanged: (String country) {
            print('You selected "$country"');
            setState(() {
              selectedCountry = country;
            });
          },
        ),
      ),
    );
  }
}

I have one article which covers detailed information about flutter dropdown

Everything You Need To know Dropdown

I have two advance dropdown article too, which cover multilevel dropdown. This could be helpful when you are working with real and complex application. Sometimes one dropdown depends on other dropdown selected data, at that point these two article is going to help you a lot.

Flutter Dropdown #