tapdown magic

main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark(),
      home: Scaffold(
        appBar: AppBar(title: const Text('Tapdown')),
        body: GestureDetector(
          onTap: () => print('tap down bottom'),
          child: Container(
            color: Colors.blue.withOpacity(0.8),
            child: Center(
              child: Container(
                width: 100,
                height: 100,
                color: Colors.green.withOpacity(0.8),
                child: GestureDetector(
                  behavior: HitTestBehavior.deferToChild,
                  onTap: () => print('tap down top'),
                  child: Center(
                    child: Container(
                      width: 50,
                      height: 50,
                      color: Colors.yellow,
                    ),
                  ),
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}