How to Set default value for dropdown button in flutter?

Hello Guys How are you all? Hope You all are fine. Today we are going to learn How to Set default value for dropdown button in a flutter. So today Here I come with all possible solutions for this error.

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Table of Contents

How to Set default value for dropdown button in flutter?
To Set the default value for the dropdown button in flutter you just need to use the value property of the dropdown button widget and give one of your Item values to the value property.
Set default value for dropdown button in flutter
To Set the default value for the dropdown button in flutter you just need to use the value property of the dropdown button widget and give one of your Item values to the value property.

Solution 1

Complete Source Code

import 'package:flutter/material.dart';

import '../config/app_theme.dart';

class DropdownWidget extends StatefulWidget {
  final String title;
  final List<String> items;
  final ValueChanged<String> itemCallBack;
  final String currentItem;
  final String hintText;

  DropdownWidget({
    this.title,
    this.items,
    this.itemCallBack,
    this.currentItem,
    this.hintText,
  });

  @override
  State<StatefulWidget> createState() => _DropdownState(currentItem);
}

class _DropdownState extends State<DropdownWidget> {
  List<DropdownMenuItem<String>> dropDownItems = [];
  String currentItem;
  AppTheme appTheme;

  _DropdownState(this.currentItem);

  @override
  void initState() {
    super.initState();
    for (String item in widget.items) {
      dropDownItems.add(DropdownMenuItem(
        value: item,
        child: Text(
          item,
          style: TextStyle(
            fontSize: 16,
          ),
        ),
      ));
    }
  }

  @override
  void didUpdateWidget(DropdownWidget oldWidget) {
    if (this.currentItem != widget.currentItem) {
      setState(() {
        this.currentItem = widget.currentItem;
      });
    }
    super.didUpdateWidget(oldWidget);
  }

  @override
  Widget build(BuildContext context) {
    appTheme = AppTheme(Theme.of(context).brightness);

    return Container(
      margin: EdgeInsets.symmetric(vertical: 10),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: <Widget>[
          Container(
            margin: EdgeInsets.only(left: 6),
            child: Text(
              widget.title,
              style: appTheme.activityAddPageTextStyle,
            ),
          ),
          Container(
            padding: EdgeInsets.symmetric(vertical: 3, horizontal: 15),
            margin: EdgeInsets.only(top: 10),
            decoration: BoxDecoration(
              borderRadius: BorderRadius.circular(6),
              color: Colors.white,
              boxShadow: [
                BoxShadow(
                  offset: Offset(0, 2),
                  blurRadius: 10,
                  color: Color(0x19000000),
                ),
              ],
            ),
            child: DropdownButtonHideUnderline(
              child: DropdownButton(
                icon: appTheme.activityAddPageDownArrowSVG,
                value: currentItem,
                isExpanded: true,
                items: dropDownItems,
                onChanged: (selectedItem) => setState(() {
                  currentItem = selectedItem;
                  widget.itemCallBack(currentItem);
                }),
                hint: Container(
                  child: Text(widget.hintText, style: appTheme.hintStyle),
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}

Summery

So, It’s All About This Error. I hope this tutorial helps you to Solve your error. Please Comment Below if You stucks anywhere with my code. And please comment below on which solution worked for you. Thank You.