TapScaleAnimated.dart

import 'package:flutter/material.dart';

class TapScaleAnimated extends StatefulWidget {

  final Widget child;
  final Function onTap;
  final double scale;

  TapScaleAnimated({this.child, @required this.onTap, this.scale = 0.9});

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

class _TapScaleAnimatedState extends State<TapScaleAnimated> with SingleTickerProviderStateMixin {
  AnimationController _scaleController;

  @override
  void initState() {
    super.initState();
    _scaleController = AnimationController(
      vsync: this,
      duration: Duration(milliseconds: 200),
      lowerBound: 0,
      upperBound: 1 - widget.scale
    )..addListener(() {
      setState(() {});
    });
  }

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

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTapDown: (details){
        _scaleController.forward();
      },
      onTapUp: (details){
        _scaleController.reverse();
        widget.onTap();
      },
      child: Transform.scale(
        scale: 1 - _scaleController.value,
        child: widget.child,
      ),
    );
  }
}