tappable.dart

import 'package:flutter/material.dart';

class Tappable extends StatefulWidget {
  const Tappable({
    super.key,
    required this.onPressed,
    required this.child,
  });

  final VoidCallback? onPressed;

  final Widget child;

  @override
  State<Tappable> createState() => _TappableState();
}

class _TappableState extends State<Tappable> {
  var pressed = false;

  @override
  Widget build(BuildContext context) {
    final disabled = widget.onPressed == null;

    return GestureDetector(
      onTap: widget.onPressed,
      onTapDown: (_) => setState(() => pressed = true),
      onTapUp: (_) => setState(() => pressed = false),
      onTapCancel: () => setState(() => pressed = false),
      child: AnimatedOpacity(
        opacity: pressed || disabled ? 0.5 : 1.0,
        duration: const Duration(milliseconds: 100),
        child: widget.child,
      ),
    );
  }
}