Introduction to Flutter Animation

Tutorial 2 of 5

Introduction

The goal of this tutorial is to introduce you to the world of Flutter Animation. Animation adds life to static applications, making them more interactive and engaging. By the end of this tutorial, you'll understand the core concepts of animation in Flutter and be able to apply these concepts to create your own animated user interfaces.

Prerequisites for this tutorial are:
- Basic understanding of Flutter and Dart
- Basic knowledge of Stateful and Stateless widgets

Step-by-Step Guide

Understanding the Basics

In Flutter, animations are values that can change over a certain duration. These animations are encapsulated within an Animation object. The Animation object in Flutter is an abstract class that understands its current value and its state (completed or dismissed).

Animation Controller

The AnimationController is a special type of Animation object that generates a new value whenever the hardware is ready for a new frame. It’s essential for controlling the animation.

Tweens

Tween is a stateless object that takes only a beginning and an ending value. The Tween object interpolates output for a given input value.

Curves

Curves define how the animation should occur. For example, should it start slow and then speed up? Flutter provides a list of curves, but you can also create your own.

Code Examples

Creating a Basic Animation

Below is a simple example of a Flutter animation:

// Importing Flutter Material Package
import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(home: MyApp())); // Running the App
}

class MyApp extends StatefulWidget {
  @override
  MyAppState createState() => MyAppState();
}

class MyAppState extends State<MyApp> with SingleTickerProviderStateMixin {
  Animation animation;
  AnimationController controller;

  @override
  initState() {
    super.initState();
    controller = AnimationController(
        duration: const Duration(seconds: 2), vsync: this);
    animation = Tween(begin: 0.0, end: 300.0).animate(controller)
      ..addListener(() {
        setState(() {
          // State change here
        });
      });
    controller.forward();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        height: animation.value,
        width: animation.value,
        child: FlutterLogo(),
      ),
    );
  }

  @override
  dispose() {
    controller.dispose();
    super.dispose();
  }
}

Summary

In this tutorial, we discussed the basics of Flutter animation, including Animation, AnimationController, Tween, and Curve. We also created a simple app where a Flutter logo increases in size over time.

To continue learning, you can explore other types of animations in Flutter, such as sequential animation and parent-child animation.

Practice Exercises

Exercise 1: Create an animation where a container changes its color over time.
Exercise 2: Create an animation that moves a Flutter logo from left to right.

Solutions and explanations will be provided for these exercises in the next tutorial. Keep practicing and exploring more about Flutter animations.