Flutter Mobile Development · Lezione

TabBar e Drawer

Implementi pattern di navigazione comuni come TabBar per visualizzazioni multiple e Drawer per i menu di navigazione laterali.

TabBar e Drawer è una lezione Flutter Mobile Development gratuita su CoddyKit. Questa è la lezione 3 di 4. Puoi leggere la lezione completa qui gratuitamente — poi esercitati direttamente nel browser con un editor di codice integrato e un tutor IA disponibile 24/7. Fa parte del percorso di apprendimento Flutter Mobile Development, e i tuoi progressi si sincronizzano tra il web e l'app CoddyKit. Il corso Flutter Mobile Development include 4 lezioni in totale.

Parti di questa lezione non sono ancora state tradotte e vengono mostrate in inglese.

Intro to Navigation Patterns

Flutter offers powerful patterns for app navigation. Today, we explore two common ones: TabBars and Drawers.

These widgets help users navigate between different sections of your app smoothly and intuitively.

TabBars are great for switching between related views.
Drawers provide a side menu for global navigation or settings.

What are TabBars?

A TabBar is a horizontal row of tabs, often found at the top or bottom of a screen. Each tab represents a different view or category of content.

When a user taps a tab, the content below it changes without leaving the current screen.

Building a Basic TabBar

To use tabs, you often wrap your Scaffold with a DefaultTabController. This controller manages the selected tab.

Then, place a TabBar widget inside your AppBar's bottom property or as a BottomNavigationBar.

import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: DefaultTabController(
        length: 3, // Number of tabs
        child: Scaffold(
          appBar: AppBar(
            title: const Text('My Tab App'),
            bottom: const TabBar(
              tabs: [
                Tab(icon: Icon(Icons.home), text: 'Home'),
                Tab(icon: Icon(Icons.settings), text: 'Settings'),
                Tab(icon: Icon(Icons.info), text: 'Info'),
              ],
            ),
          ),
          body: const TabBarView(
            children: [
              Center(child: Text('Home Content')),
              Center(child: Text('Settings Content')),
              Center(child: Text('Info Content')),
            ],
          ),
        ),
      ),
    );
  }
}

TabBarView in Action

The TabBarView widget works hand-in-hand with TabBar. It displays the content corresponding to the currently selected tab.

Make sure the number of children in TabBarView matches the length of your DefaultTabController and the number of Tab widgets.

import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: DefaultTabController(
        length: 3, // Must match the number of tabs
        child: Scaffold(
          appBar: AppBar(
            title: const Text('Tab Views'),
            bottom: const TabBar(
              tabs: [
                Tab(text: 'Explore'),
                Tab(text: 'Favorites'),
                Tab(text: 'Profile'),
              ],
            ),
          ),
          body: TabBarView( // Content for each tab
            children: [
              Center(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: const [
                    Icon(Icons.explore, size: 80, color: Colors.blue),
                    Text('Explore new content!', style: TextStyle(fontSize: 20)),
                  ],
                ),
              ),
              Center(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: const [
                    Icon(Icons.favorite, size: 80, color: Colors.red),
                    Text('Your favorite items.', style: TextStyle(fontSize: 20)),
                  ],
                ),
              ),
              Center(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: const [
                    Icon(Icons.person, size: 80, color: Colors.green),
                    Text('Your user profile.', style: TextStyle(fontSize: 20)),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

Styling Your Tabs

You can customize the look of your TabBar. For example, change colors, indicator styles, or label styles.

The indicatorColor and labelColor properties are common ways to match your app's theme.

import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: DefaultTabController(
        length: 2,
        child: Scaffold(
          appBar: AppBar(
            title: const Text('Custom Tabs'),
            bottom: TabBar(
              indicatorColor: Colors.yellowAccent, // Custom indicator color
              labelColor: Colors.white,            // Color for selected tab
              unselectedLabelColor: Colors.grey[400], // Color for unselected tabs
              tabs: const [
                Tab(icon: Icon(Icons.call), text: 'Calls'),
                Tab(icon: Icon(Icons.chat), text: 'Chats'),
              ],
            ),
          ),
          body: const TabBarView(
            children: [
              Center(child: Text('Calls Log')),
              Center(child: Text('Chat Messages')),
            ],
          ),
        ),
      ),
    );
  }
}

What is a Drawer?

A Drawer is a panel that slides out from the side of the screen, typically from the left. It's often used for main navigation links or global settings.

Drawers are perfect for apps with many sections that don't fit into a TabBar or BottomNavigationBar.

Adding a Side Drawer

To add a drawer, simply include a Drawer widget as a child of your Scaffold. Flutter automatically adds a menu icon to your AppBar.

Inside the Drawer, you'll typically use a ListView to hold multiple ListTile widgets, representing navigation items.

import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('My Drawer App'),
        ),
        drawer: Drawer( // The Drawer widget
          child: ListView(
            padding: EdgeInsets.zero, // Remove padding
            children: <Widget>[
              const DrawerHeader( // Top part of the drawer
                decoration: BoxDecoration(
                  color: Colors.blue,
                ),
                child: Text(
                  'App Menu',
                  style: TextStyle(
                    color: Colors.white,
                    fontSize: 24,
                  ),
                ),
              ),
              ListTile( // A navigation item
                leading: const Icon(Icons.message),
                title: const Text('Messages'),
                onTap: () {
                  // Handle tap
                  Navigator.pop(context); // Close the drawer
                },
              ),
              ListTile(
                leading: const Icon(Icons.account_circle),
                title: const Text('Profile'),
                onTap: () {
                  // Handle tap
                  Navigator.pop(context);
                },
              ),
              ListTile(
                leading: const Icon(Icons.settings),
                title: const Text('Settings'),
                onTap: () {
                  // Handle tap
                  Navigator.pop(context);
                },
              ),
            ],
          ),
        ),
        body: const Center(
          child: Text('Pull from left to open drawer!'),
        ),
      ),
    );
  }
}

Handling Drawer Taps

When a user taps an item in the drawer, you usually want to perform an action, like navigating to a new screen or updating content.

Remember to call Navigator.pop(context) after an item is tapped to close the drawer, providing a smooth user experience.

import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Drawer Actions'),
        ),
        drawer: Drawer(
          child: ListView(
            padding: EdgeInsets.zero,
            children: <Widget>[
              const DrawerHeader(
                decoration: BoxDecoration(color: Colors.green),
                child: Text('Navigation', style: TextStyle(color: Colors.white)),
              ),
              ListTile(
                leading: const Icon(Icons.home),
                title: const Text('Go Home'),
                onTap: () {
                  // Close drawer, then navigate (or just close if already on home)
                  Navigator.pop(context);
                  // Example: Navigator.push(context, MaterialPageRoute(builder: (context) => HomeScreen()));
                },
              ),
              ListTile(
                leading: const Icon(Icons.bookmark),
                title: const Text('View Bookmarks'),
                onTap: () {
                  Navigator.pop(context); // Close drawer
                  // Show a snackbar as an example action
                  ScaffoldMessenger.of(context).showSnackBar(
                    const SnackBar(content: Text('Viewing Bookmarks!'))
                  );
                },
              ),
            ],
          ),
        ),
        body: const Center(
          child: Text('Try opening the drawer and tapping an item.'),
        ),
      ),
    );
  }
}

Customizing Your Drawer

Drawers can be highly customized. You can add user profile info, app version, or even search bars.

Use UserAccountsDrawerHeader for a pre-built header with user info.
Keep the number of items manageable to avoid clutter.
Group related items logically using dividers.

TabBar vs. Drawer

Which of the following scenarios is best suited for using a Flutter TabBar?

TabBars & Drawers Recap

Great job! You've learned how to implement two essential navigation patterns:

TabBars for switching between related views using DefaultTabController, TabBar, and TabBarView.
Drawers for side navigation menus using the Drawer widget and ListTiles.

Choose the right pattern based on your app's complexity and user flow. Keep exploring to build more intuitive UIs!

Domande Frequenti

La lezione «TabBar e Drawer» è gratuita?

Sì — il testo completo di «TabBar e Drawer» è gratuito qui sul web. Per esercitarvi in modo interattivo (un editor di codice integrato e un tutor IA 24/7) e sbloccare il resto del corso Flutter Mobile Development, passa a CoddyKit PRO. Il corso Flutter Mobile Development include 4 lezioni in totale.

Cosa imparerò in «TabBar e Drawer»?

Implementi pattern di navigazione comuni come TabBar per visualizzazioni multiple e Drawer per i menu di navigazione laterali. Eserciti Flutter Mobile Development con codice pratico che esegui direttamente nel browser, e un tutor IA 24/7 risponde alle tue domande mentre lavori sulla lezione.

Ho bisogno di esperienza per iniziare Flutter Mobile Development?

Non è richiesta alcuna esperienza precedente. Flutter Mobile Development su CoddyKit è strutturato per principianti e studenti avanzati, quindi puoi iniziare da qui o dall'inizio e procedere al tuo ritmo. Questa è la lezione 3 di 4.

Quanto tempo richiede la lezione «TabBar e Drawer»?

La maggior parte delle lezioni CoddyKit richiede circa 5–10 minuti. Ogni lezione è breve e interattiva, quindi fai progressi costanti e riprendi esattamente da dove hai lasciato su web e app.

Posso scrivere ed eseguire codice in questa lezione Flutter Mobile Development?

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