using animation controller how to move an item in circular path in flutter code example
Example: how to move an item in circular path in using animation controller in flutter
import 'dart:ui';
import 'package:flutter/material.dart';
class SampleAnimation extends StatefulWidget{
SampleAnimation();
@override
State<StatefulWidget> createState() {
return SampleAnimationState();
}
}
class SampleAnimationState extends State<SampleAnimation> with SingleTickerProviderStateMixin {
AnimationController _controller;
Animation _animation;
Path _path;
@override
void initState() {
_controller = AnimationController(vsync: this,duration: Duration(milliseconds: 5000));
super.initState();
_animation = Tween(begin: 0.0,end: 1.0).animate(_controller)
..addListener((){
setState(() {
});
});
_controller.forward();
_path = drawPath();
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Stack(
children: <Widget>[
Positioned(
top: 0,
child: CustomPaint(
painter: PathPainter(_path),
),
),
Positioned(
top: calculate(_animation.value).dy,
left: calculate(_animation.value).dx,
child: Container(
decoration: BoxDecoration(
color: Colors.blueAccent,
borderRadius: BorderRadius.circular(10)
),
width: 10,
height: 10,
),
),
],
),
);
}
@override
void dispose() {
_controller.dispose();
super.dispose();
}
Path drawPath(){
Size size = Size(300,300);
Path path = Path();
path.moveTo(0, size.height / 2);
path.quadraticBezierTo(size.width / 2, size.height, size.width, size.height / 2);
return path;
}
Offset calculate(value) {
PathMetrics pathMetrics = _path.computeMetrics();
PathMetric pathMetric = pathMetrics.elementAt(0);
value = pathMetric.length * value;
Tangent pos = pathMetric.getTangentForOffset(value);
return pos.position;
}
}
class PathPainter extends CustomPainter {
Path path;
PathPainter(this.path);
@override
void paint(Canvas canvas, Size size) {
Paint paint = Paint()
..color = Colors.redAccent.withOpacity(0.3)
..style = PaintingStyle.stroke
..strokeWidth = 3.0;
canvas.drawPath(this.path, paint);
}
@override
bool shouldRepaint(CustomPainter oldDelegate) => true;
}