typed_json.dart

import 'dart:convert';

void main() {
  String someJson = """{
   "iceCreams": [
      {
         "flavor": "raspberry",
         "color": "red"
      },
      {
         "flavor": "banana",
         "color": "yellow"
      }
   ]
  }""";

  var json = jsonDecode(someJson);


  // (Part 2) should print raspberry
  // print(json[[0]["flavor"]);
  
  // mnazim:
  // json is a map, not an array.
  // It cannot be accessed with an index. 
  print(json['iceCreams'][0]['flavor']);

  // (Part 3) how is this even possible?
  // print(json["iceCreams"][0].toUpperCase());
  
  // mnazim:
  // json['iceCreams'][0] is a map.
  // it must be cast to string before trying to uppercase it, like so,
  print(json['iceCreams'][0].toString().toUpperCase());
  
  // or like so,
  print('${json['iceCreams'][0]}'.toUpperCase());
  
}

vertical_list_layout.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // mnazim: made key nullable
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(),
        body: Column(
          children: [
            for (int i = 0; i < 3; i++)
              Column(
                children: [
                  Text(
                    "Set $i",
                    style: Theme.of(context).textTheme.headline6,
                  ),
                  Padding(
                    padding: const EdgeInsets.all(8.0),
                    child: MyListView(i: i),
                  ),
                ],
              ),
          ],
        ),
      ),
    );
  }
}

class MyListView extends StatelessWidget {
  const MyListView({
    Key? key,
    required this.i,
  }) : super(key: key);

  final int i;

  @override
  Widget build(BuildContext context) {
    // mnazim: ListView does not have an intrinsic height,
    // since it was nested in a column and column takes the height of it's children,
    // this constraint was not solvable by flutter automatically.
    // solution:
    // extract to a separate widget, so MediaQuery can be accessed.
    // provide a fixed height (based on available height) for the ListView

    return SizedBox(
      height: MediaQuery.of(context).size.height / 4,
      child: ListView(
        children: [
          for (int j = 0; j < 100; j++)
            Center(
              child: Text("{$i, $j}"),
            ),
        ],
      ),
    );
  }
}