Flutter Paint Line Rotate 360 Demo

main.dart

// Code Licensed under the Apache License, Version 2.0 - visit : https://github.com/akshatapp/flutter-gist/blob/master/LICENSE

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Paint Line Rotate 360 Demo',
      debugShowCheckedModeBanner: false,
      // showPerformanceOverlay: true,
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage>
    with SingleTickerProviderStateMixin {
  AnimationController _animationController;

  @override
  void initState() {
    super.initState();
    _animationController =
        AnimationController(duration: Duration(seconds: 15), vsync: this)
          ..repeat();
  }

  @override
  void dispose() {
    _animationController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final lineLength = getLineLength(context);
    return Scaffold(
      backgroundColor: Colors.white,
      body: Center(
        child: RotationTransition(
          turns: _animationController,
          child: CustomPaint(
            painter: MyPaint(lineLength),
          ),
        ),
      ),
    );
  }
}

class MyPaint extends CustomPainter {
  final length;
  MyPaint(this.length);

  @override
  void paint(Canvas canvas, Size size) {
    final center = (Offset.zero & size).center;

    final position = center + Offset(0.0, -1.0) * length;

    final linePaint = Paint()
      ..color = Colors.red
      ..strokeWidth = 4.0
      ..strokeCap = StrokeCap.round;

    canvas.drawLine(center, position, linePaint);
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return false;
  }
}

double getLineLength(context) {
  final shortSide = MediaQuery.of(context).size.shortestSide;
  return (shortSide * 0.25);
}