How to Add Wave Animation in Flutter

Wave animation is a popular effect used in mobile apps and web pages. It gives an illusion of movement and can be used to convey a sense of excitement or energy. In this article, we will show you how to create a wave animation in Flutter.

The animation is interesting to use in a Flutter app. It’s the foundation for a liquid motion.

WaveContainer(
width: double.infinity,
height: 50,
waveColor: Colors.orangeAccent)

class WaveContainer extends StatefulWidget {
  final Duration duration;
  final double height;
  final double width;
  final Color waveColor;

  const WaveContainer({
    Key key,
    this.duration,
    @required this.height,
    @required this.width,
    this.waveColor,
  }) : super(key: key);

  @override
  _WaveContainerState createState() => _WaveContainerState();
}

class _WaveContainerState extends State<WaveContainer>
    with TickerProviderStateMixin {
  AnimationController _animationController;
  Duration _duration;
  Color _waveColor;

  @override
  void initState() {
    super.initState();

    _duration = widget.duration ?? const Duration(milliseconds: 1000);
    _animationController = AnimationController(vsync: this, duration: _duration);
    _waveColor = widget.waveColor ?? Colors.lightBlueAccent;

    _animationController.repeat();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      width: widget.width,
      height: widget.height,
      child: AnimatedBuilder(
        animation: _animationController,
        builder: (BuildContext context, Widget child) {
          return CustomPaint(
            painter: WavePainter(
                waveAnimation: _animationController, waveColor: _waveColor),
          );
        },
      ),
    );
  }

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

class WavePainter extends CustomPainter {
  Animation<double> waveAnimation;
  Color waveColor;

  WavePainter({this.waveAnimation, this.waveColor});

  @override
  void paint(Canvas canvas, Size size) {
    Path path = Path();
    for (double i = 0.0; i < size.width; i++) {
      path.lineTo(i,
          sin((i / size.width * 2 * pi) + (waveAnimation.value * 2 * pi)) * 4);
    }
    path.lineTo(size.width, size.height);
    path.lineTo(0.0, size.height);
    path.close();

    Paint wavePaint = Paint()..color = waveColor;
    canvas.drawPath(path, wavePaint);
  }

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