As you progress in your Flutter journey, you'll come across the need for more advanced animations to create a visually appealing user experience. Flutter offers a plethora of tools and libraries to help you create complex animations.
Advanced Animation in Flutter π₯
1. Animation Controller ποΈ
The AnimationController
is a powerful tool that not only controls the animation, but also the speed, duration, and much more. It can be used to create more complex animations by controlling the behavior of the animation over time.
Copy AnimationController controller = AnimationController (
duration : const Duration (seconds : 2 ),
vsync : this,
);
2. CurvedAnimation π
CurvedAnimation
allows you to apply a non-linear curve to an animation, which can make the movement feel more natural.
Copy Animation curve = CurvedAnimation (
parent : controller,
curve : Curves .easeInOut,
);
3. Animation Sequences π
With Interval
, you can control the portion of an animation's duration when a range of values is used.
Copy Animation < double > tween = Tween < double >(begin : 0 , end : 300 ). animate (
CurvedAnimation (
parent : controller,
curve : Interval (
0.5 , 1.0 ,
curve : Curves .fastOutSlowIn,
),
),
);
4. Staggered Animations π«
Staggered animations are a sequence of animations that run one after the other.
Copy Animation < double > tween = Tween < double >(begin : 0 , end : 300 ). animate (
CurvedAnimation (
parent : controller,
curve : Interval (
0 , 0.6 ,
curve : Curves .ease,
),
),
);
Let's Understand An Advanced Animation Example π
Code Animation
Copy // Copyright 2020 the Dart project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license
// that can be found in the LICENSE file.
import 'dart:math' ;
import 'package:flutter/material.dart' ;
class DiscData {
static final _rng = Random ();
final double size;
final Color color;
final Alignment alignment;
DiscData ()
: size = _rng. nextDouble () * 40 + 10 ,
color = Color . fromARGB (
_rng. nextInt ( 200 ),
_rng. nextInt ( 255 ),
_rng. nextInt ( 255 ),
_rng. nextInt ( 255 ),
),
alignment = Alignment (
_rng. nextDouble () * 2 - 1 ,
_rng. nextDouble () * 2 - 1 ,
);
}
void main () async {
runApp (
MaterialApp (
debugShowCheckedModeBanner : false ,
theme : ThemeData . dark (useMaterial3 : true ),
home : Scaffold (
body : Container (
color : const Color ( 0xFF15202D ),
child : const SizedBox . expand (
child : VariousDiscs ( 50 ),
),
),
),
),
);
}
class VariousDiscs extends StatefulWidget {
final int numberOfDiscs;
const VariousDiscs (this.numberOfDiscs);
@override
State < VariousDiscs > createState () => _VariousDiscsState ();
}
class _VariousDiscsState extends State < VariousDiscs > {
final _discs = < DiscData > [];
@override
void initState () {
super. initState ();
_makeDiscs ();
}
void _makeDiscs () {
_discs. clear ();
for ( int i = 0 ; i < widget.numberOfDiscs; i ++ ) {
_discs. add ( DiscData ());
}
}
@override
Widget build ( BuildContext context) {
return Stack (
children : [
const Center (
child : Text (
'Click a disc!' ,
style : TextStyle (color : Colors .white, fontSize : 50 ),
),
),
GestureDetector (
onTap : () => setState (() {
_makeDiscs ();
}),
child : Stack (children : [
for ( final disc in _discs)
Positioned . fill (
child : AnimatedAlign (
duration : const Duration (milliseconds : 500 ),
curve : Curves .easeInOut,
alignment : disc.alignment,
child : AnimatedContainer (
duration : const Duration (milliseconds : 500 ),
decoration : BoxDecoration (
color : disc.color,
shape : BoxShape .circle,
),
height : disc.size,
width : disc.size,
),
),
),
]),
),
],
);
}
}
Code Explanation π
1. Import Statements π
Copy import 'dart:math' ;
import 'package:flutter/material.dart' ;
These lines import necessary libraries. The dart:math
library is used to work with random numbers, and package:flutter/material.dart
is the Material library in Flutter, which provides many widgets to build a UI.
2. DiscData Class π
Copy class DiscData {
static final _rng = Random ();
final double size;
final Color color;
final Alignment alignment;
DiscData ()
: size = _rng. nextDouble () * 40 + 10 ,
color = Color . fromARGB (
_rng. nextInt ( 200 ),
_rng. nextInt ( 255 ),
_rng. nextInt ( 255 ),
_rng. nextInt ( 255 ),
),
alignment = Alignment (
_rng. nextDouble () * 2 - 1 ,
_rng. nextDouble () * 2 - 1 ,
);
}
The DiscData
class holds information for each disc, including its size, color, and position. The constructor initializes these properties with random values.
3. Main Function π
Copy void main () async {
runApp (
MaterialApp (
debugShowCheckedModeBanner : false ,
theme : ThemeData . dark (useMaterial3 : true ),
home : Scaffold (
body : Container (
color : const Color ( 0xFF15202D ),
child : const SizedBox . expand (
child : VariousDiscs ( 50 ),
),
),
),
),
);
}
The main
function is the entry point of the Flutter app. Here, a MaterialApp
widget is created with a dark theme and a VariousDiscs
widget with 50 discs as the home screen.
4. VariousDiscs Widget π
Copy class VariousDiscs extends StatefulWidget {
final int numberOfDiscs;
const VariousDiscs (this.numberOfDiscs);
@override
State < VariousDiscs > createState () => _VariousDiscsState ();
}
The VariousDiscs
widget is a StatefulWidget
that takes the number of discs as a parameter.
5. _VariousDiscsState Class π
Copy class _VariousDiscsState extends State < VariousDiscs > {
final _discs = < DiscData > [];
@override
void initState () {
super. initState ();
_makeDiscs ();
}
void _makeDiscs () {
_discs. clear ();
for ( int i = 0 ; i < widget.numberOfDiscs; i ++ ) {
_discs. add ( DiscData ());
}
}
@override
Widget build ( BuildContext context) {
return Stack (
children : [
const Center (
child : Text (
'Click a disc!' ,
style : TextStyle (color : Colors .white, fontSize : 50 ),
),
),
GestureDetector (
onTap : () => setState (() {
_makeDiscs ();
}),
child : Stack (children : [
for ( final disc in _discs)
Positioned . fill (
child : AnimatedAlign (
duration : const Duration (milliseconds : 500 ),
curve : Curves .easeInOut,
alignment : disc.alignment,
child : AnimatedContainer (
duration : const Duration (milliseconds : 500 ),
decoration : BoxDecoration (
color : disc.color,
shape : BoxShape .circle,
),
height : disc.size,
width : disc.size,
),
),
),
]),
),
],
);
}
}
The _VariousDiscsState
class manages the state of the VariousDiscs
widget. It creates a list of DiscData
objects, which are used to build a stack of animated discs. When a disc is tapped, the _makeDiscs
method is called to regenerate the list of discs, triggering a new set of animations.
Assignments π
Last updated 6 months ago