shawn.blais

Shawn has worked as programmer and product designer for over 20 years, shipping several games on Steam and Playstation and dozens of apps on mobile. He has extensive programming experience with Dart, C#, ActionScript, SQL, PHP and Javascript and a deep proficiency with motion graphics and UX design. Shawn is currently the Technical Director for gskinner.

@tree_fortress

Flutter: Lazy instantiation with the `late` keyword

With the introduction of NNBD in Dart 2.12, a new keyword was created: late. The primary reason this was created was to allow for non-null fields, that did not have to be immediately initialized.

// Allow this to be null for now, compiler trusts us, that we will assign it.
late final int i; 
MyConstructor(){
   i = getStartIndex(); // Compiler checks at this point, everything is ok!
   i = null; // This will cause an error, compiler is enforcing non-null
}

This was a necessary feature/workaround for Flutter, because of darts requirement to use const initializers, and most Flutter developers are likely familiar with it by now. In this post we’re going to look at some of the other benefits of late!

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Flokk – How we built a Desktop App Using Flutter

Earlier this year Google and Ubuntu approached us with an open brief, to try and create a full-scale desktop application for Linux, macOS, Web, and Windows. The result was Flokk, which we released (and open-sourced) back in July.

In this post, we’re going to dive into some of the challenges we faced, the discoveries we made, and desktop-specific features that we added.

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Flutter Tricks: Widget Size & Position

Occasionally in Flutter, you will need to get the size and/or position of a widget. Some common use cases for this are:

  • You need to measure something and make some decision based on that. For example, you might switch from an expanded column, to a scrolling column, at a certain height threshold.
  • You may want enable or disable a scrollbar based on the height of some content
  • The parent needs to know your position. For example if when you tap a menu button, the parent wants to animate a dot to that position, we need the button to be able to report its position somehow.
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Flutter: The new ‘animations’ package explained

The Flutter team recently dropped a great new transitions package, based on the new Material 2 design spec, the somewhat ambiguously-named: animations package.

SharedAxis Example

They are super cool to look at and appear to be highly performant. The only issue? The examples they’ve provided with the package are pretty hard to follow (coming in at close to 1500 lines!) and there’s no code snippets at all in the README.

But fear not! This package is actually extremely simple to use once you clear away the noise, and can see how it works.

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Flutter: sized_context – An easier way to access MediaQuery.size!

After sharing our simplified screen size detection example to reddit last week, we received a great suggestion from the community: the concept would work better as a set of extension methods.

The original thought was to add the methods to MediaQuery, which didn’t seem that appealing because it would still be quite verbose to access. Then we realized we could just use the build context directly, which turned out really nice! So nice, that we’ve gone ahead and created a package for it here: https://pub.dev/packages/sized_context.

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