Creare spazi tra widget in Flutter con gap

Quando dobbiamo creare degli spazi tra i widget in Flutter abbiamo una paio di  possibilità, come usare i padding o SizedBox.

Se vogliamo qualcosa di più conciso e flessibile possiamo usare gap!

Per installarlo:

flutter pub add gap

Qui sotto un esempio di codice:

import 'package:flutter/material.dart';
import 'package:gap/gap.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Test',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(
          seedColor: Colors.deepPurple,
        ),
        useMaterial3: true,
      ),
      home: const MyHomePage(),
    );
  }
}

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

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: const Text('Flutter Test'),
      ),
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Container(
            color: Colors.black,
            height: 20,
          ),
          const Gap(
            20,
            color: Colors.green,
            crossAxisExtent: 10,
          ),
          Container(
            color: Colors.black,
            height: 20,
          ),
          const Gap(
            20,
            color: Colors.amber,
            crossAxisExtent: 50,
          ),
          Container(
            color: Colors.black,
            height: 20,
          ),
          const Gap.expand(
            20,
            color: Colors.purple,
          ),
        ],
      ),
    );
  }
}

Enjoy!