DefaultsSample

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: NoStateHomePage('Zodiac Thingy', secondTitle: "basta naa ni"),
    );
  }
}

class NoStateHomePage extends StatelessWidget {
  final String title;
  final String secondTitle;
  NoStateHomePage(this.title, {this.secondTitle});
  // NoStateHomePage(this.title, this.secondTitle);
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text(title + " " + secondTitle),
        ),
        body: ContentZodiac());
  }
}

class ContentZodiac extends StatefulWidget {
  @override
  _ContentZodiacState createState() => _ContentZodiacState();
}

class _ContentZodiacState extends State<ContentZodiac> {
  int _value = 0;

  List<Map<String, dynamic>> information = [
    {},
    {
      "name": "Aries",
      "dates": "19 April – 13 May",
      "stay": "25 days",
      "brightest_star": "Hamal",
      "image":
          "https://cdn.discordapp.com/attachments/753905152796131328/770286814517919774/scorpio.jpg"
    },
    {
      "name": "Taurus",
      "dates": "14 May – 19 June",
      "stay": "37 days",
      "brightest_star": "Aldebaran",
      "image":
          "https://media.discordapp.net/attachments/753905152796131328/770286818314027048/taurus.jpg?width=789&height=789"
    },
    {
      "name": "Gemini",
      "dates": "20 June – 20 July",
      "stay": "31 days",
      "brightest_star": "Pollux",
      "image": "https://via.placeholder.com/400"
    },
    {
      "name": "Cancer",
      "dates": "21 July – 9 August",
      "stay": "20 days",
      "brightest_star": "Al Tarf",
      "image": "https://via.placeholder.com/400"
    },
    {
      "name": "Leo",
      "dates": "10 August – 15 September",
      "stay": "37 days",
      "brightest_star": "Regulus",
      "image": "https://via.placeholder.com/400"
    },
    {
      "name": "Virgo",
      "dates": "16 September – 30 October",
      "stay": "45 days",
      "brightest_star": "Spica",
      "image": "https://via.placeholder.com/400"
    },
    {
      "name": "Libra",
      "dates": "31 October – 22 November",
      "stay": "23 days",
      "brightest_star": "Zubeneschamali",
      "image": "https://via.placeholder.com/400"
    },
    {
      "name": "Scorpius",
      "dates": "23 November – 29 November",
      "stay": "7 days",
      "brightest_star": "Antares",
      "image":
          "https://cdn.discordapp.com/attachments/753905152796131328/770286814517919774/scorpio.jpg"
    },
    {
      "name": "Ophiuchus",
      "dates": "30 November – 17 December",
      "stay": "18 days",
      "brightest_star": "Rasalhague",
      "image": "https://via.placeholder.com/400"
    },
    {
      "name": "Sagittarius",
      "dates": "18 December – 18 January",
      "stay": "32 days",
      "brightest_star": "Kaus Australis",
      "image": "https://via.placeholder.com/400"
    },
    {
      "name": "Capricornus",
      "dates": "19 January – 15 February",
      "stay": "28 days",
      "brightest_star": "Deneb Algedi",
      "image": "https://via.placeholder.com/400"
    },
    {
      "name": "Aquarius",
      "dates": "16 February – 11 March",
      "stay": "24 days",
      "brightest_star": "Sadalsuud",
      "image":
          "https://cdn.discordapp.com/attachments/753905152796131328/770286395473264660/aquarius.jpg"
    },
    {
      "name": "Pisces",
      "dates": "12 March – 18 April",
      "stay": "38 days",
      "brightest_star": "Eta Piscium",
      "image": "https://via.placeholder.com/400"
    }
  ];

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: EdgeInsets.all(25),
      child: Column(
        children: [
          DropdownButton(
              value: _value,
              items: generateOptions(),
              onChanged: (value) {
                print(value);
                setState(() {
                  _value = value;
                });
              }),
          _value == 0
              ? Container()
              : Column(
                  children: [
                    Image.network(information[_value]["image"]),
                    Text("Name of zodiac: ${information[_value]["name"]}",
                        style: TextStyle(fontSize: 24)),
                    Text("Dates represented: " + information[_value]["dates"]),
                    Text(
                        "How long it is visible: ${information[_value]["stay"]}"),
                    Text(
                        "The brightest star: ${information[_value]["brightest_star"]}"),
                  ],
                ),
        ],
      ),
    );
  }

  List<DropdownMenuItem<int>> generateOptions() {
    List<DropdownMenuItem<int>> result = [
      DropdownMenuItem(
        child: Text("Select an item"),
        value: 0,
      ),
    ];

    for (int i = 1; i < information.length; i++) {
      result.add(
        DropdownMenuItem(
          child: Text(information[i]["name"]),
          value: i,
        ),
      );
    }
    return result;
  }
}