RedBrogdon

// What if you need a variable that can hold a null
// value? You can declare it nullable by adding a
// question mark to the end of the type. In this
// case, try `int?`.

void main() {
  int a;
  a = null;
  print('a is $a.');
}

RedBrogdon

// Welcome to the null safety version of DartPad!
// This is the first in a series of code examples
// designed to illustrate the new syntax and
// coding patterns for null safety.
//
// Each snippet starts off in a bad or broken
// state. You’ll probably see warnings from the
// Dart analyzer, and the code probably won't
// compile. But by following the instructions
// and making edits to the code, you can update

RedBrogdon

// Flutter code sample for NavigationRail

// This example shows a [NavigationRail] used within a Scaffold with 3
// [NavigationRailDestination]s. The main content is separated by a divider
// (although elevation on the navigation rail can be used instead). The
// `_selectedIndex` is updated by the `onDestinationSelected` callback.

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

RedBrogdon

import 'dart:math';

import 'package:flutter/material.dart';

// Colors.
const crossColor = const Color(0xFF1ABDD5);
const circleColor = const Color(0xFFD8B9FA);
const accentColor = const Color(0xFF90A4AE);

void main() => runApp(MyApp());

RedBrogdon

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {

RedBrogdon

/*
MIT License

Copyright (c) 2020 Mariano Zorrilla

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is

RedBrogdon

/*
MIT License

Copyright (c) 2020 Mariano Zorrilla

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is

RedBrogdon

//Made with dartpad.dartlang.org <3
import 'dart:async';
import 'package:flutter/material.dart';

final Color cellColor = Colors.lightBlue;
final Color bgColor = new Color.fromARGB(255, 245, 245, 255);
final TargetPlatform platform = TargetPlatform.android;

List<List<bool>> cells;
final width = 700.0, height = 700.0;

RedBrogdon

import 'package:flutter/material.dart';

void main() => runApp(
      MaterialApp(
        home: Center(
          child: Image.network(
            'http://placekitten.com/200/200',
          ),
        ),
      ),

RedBrogdon

import 'dart:async';

class MyClass {
  final myMap = <String, int>{'zero':0 };

  final controller = StreamController<List<int>>();

  void addNumber(String s, int i) {
    controller.add(myMap.entries.map((e) => e.value).toList());
    myMap[s] = i;