dissmissible_q.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: 'Demo',
      home: HomeLayout(),
    );
  }
}

class HomeLayout extends StatelessWidget {
  const HomeLayout({super.key});

  @override
  Widget build(BuildContext context) {
    return const Scaffold(
      body: SafeArea(
        child: Row(
          children: [
            Expanded(flex: 30, child: LeftWidget()),
            Expanded(flex: 60, child: RightWidget()),
          ],
        ),
      ),
    );
  }
}

class LeftWidget extends StatelessWidget {
  const LeftWidget({super.key});

  @override
  Widget build(BuildContext context) {
    return Material(
      elevation: 1,
      color: Colors.blueGrey.shade100,
      child: const Center(
        child: Text(
          "Left Widget",
          style: TextStyle(fontSize: 24),
        ),
      ),
    );
  }
}

class RightWidget extends StatefulWidget {
  const RightWidget({
    super.key,
  });

  @override
  State<RightWidget> createState() => _RightWidgetState();
}

class _RightWidgetState extends State<RightWidget> {
  double items = 0;
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        Slider(
            value: items,
            onChanged: (item) => setState(() {
                  items = item;
                })),
        Expanded(
          child: ListView.builder(
            itemCount: (items * 20).toInt(),
            itemBuilder: (context, index) => Dismissible(
              key: UniqueKey(),
              direction: DismissDirection.endToStart,
              child: Card(
                color: Colors.amber.shade100,
                child: Padding(
                  padding: const EdgeInsets.all(18.0),
                  child: Text(index.toString()),
                ),
              ),
            ),
          ),
        ),
      ],
    );
  }
}