fluttie: Lottie for flutter

Fluttie (github, pub) is a flutter plugin for displaying animations created in Lottie. Even complex animations can be displayed without having to write long custom rendering code. The library can render the animations by piping the output from the Lottie Android library into a Flutter texture.

You can download a small Flutter app for Android showing what Fluttie looks like in action. This app can also be used to easily preview animations from lottiefiles.com, which might be handy when deciding what animations to use.

Please note: At the moment, this plugin does not support iOS devices.

Things to keep in mind when using this:

  • No iOS support yet
  • Due to a delay between the dart code and the native backend, controlling multiple animations can be a bit laggy. Rendering multiple animations will reduce your app's framerate.
  • Animation widgets need a fixed size for now
  • Do not re-use animations, as this can crash your app. Instead, save the output of loadAnimationFromAsset() and construct a new animation whenever you need to.

Getting Started

The example included contains a basic, but throughoutly commented, app illustrating how to include, load and show animations in Fluttie.

In order to use animations with fluttie, you will need a json file containing the composition for your animation. You can either export it using an AfterEffects plugin (see instructions) or grab some at lottiefiles.com. A composition is a JSON file that describes everything in your animation, like the different shapes, colors and movements. Place the file in an folder inside your project and add it in the assets part of your pubspec.yaml, like its done here. If you haven't already done so, also add Fluttie to your projects' dependencies:

dependencies:
  fluttie: ^0.3.0

In order to display animations in Flutter, you will have the plugin load a composition first. The plugin will parse the composition file so that it can quickly display the animation later on.

var instance = Fluttie();
var emojiComposition = await instance.loadAnimationFromAsset(
    "assets/animations/emoji.json", //Replace this string with your actual file
);

In order to actually show the animation on screen, two parts are neccessary: An AnimationController, which controls the instance of the animation and contains methods to pause and resume it, and finally a widget displaying the animation contained by the controller.

// This creates the controller
var emojiAnimation = await instance.prepareAnimation(emojiComposition)

You can also set the duration of your animation and configure looping while preparing the animation by using the optional parameters of prepareAnimation, see the docs fore more details. After having your animation controller ready, you can include it as a widget:

Widget build(BuildContext context) =>
    FluttieAnimation(emojiAnimation)

Don't forget to start your animation by calling emojiAnimation.start() on your controller!

Questions and bugs

As the library is in an early version, there will be things not working like they should. If you encounter a bug, have a question or want some features implemented, please don't hesitate to create an issue. Of course, I would absolutely appreciate any contributions as pull requests.

Libraries

fluttie

Dart

dart:ui
Built-in types and core primitives for a Flutter application. [...]

Core

dart:async
Support for asynchronous programming, with classes such as Future and Stream. [...]
dart:collection
Classes and utilities that supplement the collection support in dart:core. [...]
dart:convert
Encoders and decoders for converting between different data representations, including JSON and UTF-8. [...]
dart:core
Built-in types, collections, and other core functionality for every Dart program. [...]
dart:developer
Interact with developer tools such as the debugger and inspector. [...]
dart:math
Mathematical constants and functions, plus a random number generator. [...]
dart:typed_data
Lists that efficiently handle fixed sized data (for example, unsigned 8 byte integers) and SIMD numeric types. [...]

VM

dart:io
File, socket, HTTP, and other I/O support for non-web applications. [...]
dart:isolate
Concurrent programming using isolates: independent workers that are similar to threads but don't share memory, communicating only via messages. [...]