mraleph

This step by step guide uses issue RegEx: add a way to get the positions of groups #42307 as a concrete example. You can also watch associated videos:

• Contributing a change to Dart SDK Core Libraries (Part 1)
• Contributing a change to Dart SDK Core Libraries (Part 2): Responding to a Review

Step 0: Ask the team

Ask Dart team before jumping into the implementation. The best place to ask is on the issue tracker, you can also try hackers-dart channel on Flutter Discord or one of the channels on Dart Community discord - but most SDK developers are not on either of them.

Why ask the team?

MaherSafadii

1. The new CupertinoSliverNavigationbar.search searchfield bar has incorrect horizontal padding and placement.

2. The Cupertino wheel picker doesn't have the fade out effect for the items when they go out of view like with native.

3. The Cupertino wheel picker doesn't make the native tick sound effect when the selected item is changed, i tried playing aroung once to try and fix it, turns out the tick sound is a system sound that you can play using the AudioToolBox (iOS framework), you play the sound by running udioServicesPlaySystemSoundWithCompletion(1157, nil), 1157 is the id of the system sound.

4. There isn't a proper up-to-date toolbar API, instead we only have just trailing and leading for Cupertino nav bars, on native there is a extensive API that allows you to specify that widgets location, including on the bottom of the screen not just the top navigation bar, since the bottom is also considered a toolbar.

5. Adding widgets to CupertinoNavigationBar's leading and trailing is a painful chore, on na

lukepighetti

import '/features/architecture/logging.dart';

class CachedQuery<T> {
  final Duration invalidation;
  final Future<T> Function(String key) fn;

  CachedQuery(
    this.fn,
    this.invalidation,
  );

AkinAguda

// Convert string to number
type ToNumber<S> = S extends `${infer N extends number}` ? N : never;

// Creates an array with a particular length
type ArrayWithLength<
  T extends number,
  A extends number[] = number[],
> = A["length"] extends T ? A : ArrayWithLength<T, [...A, A["length"]]>;

// Generates a union type with all the numbers from zero -> n

BarryDaBee

import 'package:flutter/material.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

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

class MyApp extends StatefulWidget {
  @override

craiglabenz

import 'dart:math';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';

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

class MyApp extends StatelessWidget {
  @override

medwonuola

import 'dart:math';

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

ConnerWill

ANSI Escape Sequences

Standard escape codes are prefixed with Escape:

• Ctrl-Key: ^[
• Octal: \033
• Unicode: \u001b
• Hexadecimal: \x1B
• Decimal: 27

jogboms

Demystifying the journey from Widget to the RenderObject.

These are Dartpad links to the examples. Full repo can be found jogboms/flutter_guild_demo

Widget ・ Gist ・ Dartpad

Multi-Child layout ・ Gist ・ Dartpad

CustomPainter ・ Gist ・ Dartpad

jogboms

import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';

class Space extends LeafRenderObjectWidget {
  const Space(this.space, {Key? key}) : super(key: key);

  final double space;

  @override
  RenderObject createRenderObject(BuildContext context) => RenderSpace(space: space);