Flutter Mobile Development · レッスン

TabBarとDrawer

複数のビューに対応するTabBarや、サイドナビゲーションメニューのDrawerなど、一般的なナビゲーションパターンを実装します。

「TabBarとDrawer」はCoddyKit上の無料Flutter Mobile Developmentレッスンです。これはレッスン3/4です。下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。これはFlutter Mobile Development学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 Flutter Mobile Developmentコースには全4レッスンが含まれています。

このレッスンの一部はまだ翻訳されておらず、英語で表示されています。

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!

よくある質問

「TabBarとDrawer」レッスンは無料ですか？

はい。「TabBarとDrawer」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、Flutter Mobile Developmentコースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 Flutter Mobile Developmentコースには全4レッスンが含まれています。

「TabBarとDrawer」で何を学びますか？

複数のビューに対応するTabBarや、サイドナビゲーションメニューのDrawerなど、一般的なナビゲーションパターンを実装します。ブラウザで直接実行するハンズオンコードでFlutter Mobile Developmentを演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。

Flutter Mobile Developmentを始めるのに経験は必要ですか？

事前経験は必要ありません。CoddyKitのFlutter Mobile Developmentは初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。これはレッスン3/4です。

「TabBarとDrawer」レッスンにはどのくらい時間がかかりますか？

ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。

このFlutter Mobile Developmentレッスンでコードを書いて実行できますか？

はい。すべてのFlutter Mobile Developmentレッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。

このコースのすべてのレッスン

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