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: Creating your own Inherited Widgets

While we generally use Provider or GetIt to pass things around in Flutter, there are times when you don’t want to have any dependencies on these libraries, and instead just want to define your own MyFoo.of(context) lookup. Often this is when you’re creating packages yourself.

There are quite a few deep dives tutorials into this around, but in this post we wanted to keep it extremely short and sweet.

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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: Extending State‹T›

Recently we’ve been exploring the ability to extend the base State<T> class, to add additional capabilities to our views, or writing our own custom Mixins to do the same.

Most Developers are familiar with using the various framework Mixins, like TickerProviderStateMixin but what is not commonly known, is how easy it is to create your own flavors of these. Additionally, many developers extend State<T> constantly, and write very repetitive boilerplate code, without realizing how easy it is to create their own BaseState<T> instead.

In this example, we’ll make a “base state” that provides 3 AnimatorControllers to any widget that needs to animate something. We could then apply this to any Widget in our application, and it automatically get 3 animators to play with. No setup, or teardown required.

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