Ripple animation flutter - flutter

Question

I want to create ripple animation using flutter. I already know ripple effect but this is not what I want , I want something which is here in the link

Answer 1

Output
AnimationController _controller;
#override
void initState() {
super.initState();
_controller = AnimationController(
vsync: this,
lowerBound: 0.5,
duration: Duration(seconds: 3),
)..repeat();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text("Title")),
body: _buildBody(),
);
}
Widget _buildBody() {
return AnimatedBuilder(
animation: CurvedAnimation(parent: _controller, curve: Curves.fastOutSlowIn),
builder: (context, child) {
return Stack(
alignment: Alignment.center,
children: <Widget>[
_buildContainer(150 * _controller.value),
_buildContainer(200 * _controller.value),
_buildContainer(250 * _controller.value),
_buildContainer(300 * _controller.value),
_buildContainer(350 * _controller.value),
Align(child: Icon(Icons.phone_android, size: 44,)),
],
);
},
);
}
Widget _buildContainer(double radius) {
return Container(
width: radius,
height: radius,
decoration: BoxDecoration(
shape: BoxShape.circle,
color: Colors.blue.withOpacity(1 - _controller.value),
),
);
}

Answer 2

Here is another version using CustomPaint
import 'dart:math' as math show sin, pi, sqrt;
import 'package:flutter/animation.dart';
import 'package:flutter/material.dart';
class Ripples extends StatefulWidget {
const Ripples({
Key key,
this.size = 80.0,
this.color = Colors.pink,
this.onPressed,
#required this.child,
}) : super(key: key);
final double size;
final Color color;
final Widget child;
final VoidCallback onPressed;
#override
_RipplesState createState() => _RipplesState();
}
class _CirclePainter extends CustomPainter {
_CirclePainter(
this._animation, {
#required this.color,
}) : super(repaint: _animation);
final Color color;
final Animation<double> _animation;
void circle(Canvas canvas, Rect rect, double value) {
final double opacity = (1.0 - (value / 4.0)).clamp(0.0, 1.0);
final Color _color = color.withOpacity(opacity);
final double size = rect.width / 2;
final double area = size * size;
final double radius = math.sqrt(area * value / 4);
final Paint paint = Paint()..color = _color;
canvas.drawCircle(rect.center, radius, paint);
}
#override
void paint(Canvas canvas, Size size) {
final Rect rect = Rect.fromLTRB(0.0, 0.0, size.width, size.height);
for (int wave = 3; wave >= 0; wave--) {
circle(canvas, rect, wave + _animation.value);
}
}
#override
bool shouldRepaint(_CirclePainter oldDelegate) => true;
}
class _RipplesState extends State<Ripples> with TickerProviderStateMixin {
AnimationController _controller;
#override
void initState() {
super.initState();
_controller = AnimationController(
duration: const Duration(milliseconds: 2000),
vsync: this,
)..repeat();
}
#override
void dispose() {
_controller.dispose();
super.dispose();
}
Widget _button() {
return Center(
child: ClipRRect(
borderRadius: BorderRadius.circular(widget.size),
child: DecoratedBox(
decoration: BoxDecoration(
gradient: RadialGradient(
colors: <Color>[
widget.color,
Color.lerp(widget.color, Colors.black, .05)
],
),
),
child: ScaleTransition(
scale: Tween(begin: 0.95, end: 1.0).animate(
CurvedAnimation(
parent: _controller,
curve: const _PulsateCurve(),
),
),
child: widget.child,
),
),
),
);
}
#override
Widget build(BuildContext context) {
return CustomPaint(
painter: _CirclePainter(
_controller,
color: widget.color,
),
child: SizedBox(
width: widget.size * 2.125,
height: widget.size * 2.125,
child: _button(),
),
);
}
}
class _PulsateCurve extends Curve {
const _PulsateCurve();
#override
double transform(double t) {
if (t == 0 || t == 1) {
return 0.01;
}
return math.sin(t * math.pi);
}
}