React Native Academy · レッスン

ローカル通知のスケジュール設定

expo-notificationsをインストールして権限をリクエストし、遅延後に発火するローカル通知をスケジュールして、通知のタップで特定の画面へ移動できるようにします

「ローカル通知のスケジュール設定」はCoddyKit上の無料React Native Academy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React Native Academy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。 React Native Academy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。

What Are Local Notifications?

Local notifications are alerts that your app schedules and delivers entirely on-device, without a server. Unlike push notifications, they do not require an internet connection or a backend service. They are ideal for reminders, daily habit prompts, timer alerts, and in-app alerts that trigger after a specific time or based on a recurring schedule.

Installing expo-notifications

Install expo-notifications using the Expo install command so the SDK-compatible version is selected. In managed Expo projects native linking is automatic. Also add the notification configuration block to app.json to set the Android notification icon and color used by the OS.

npx expo install expo-notifications

// app.json:
{
  "expo": {
    "notification": {
      "icon": "./assets/notification-icon.png",
      "color": "#6200ee",
      "androidMode": "default"
    }
  }
}

Requesting Notification Permission

On both iOS and Android you must request notification permission before scheduling any notification. iOS requires explicit user approval — the system shows a dialog. Android 13+ also requires runtime permission. Call Notifications.requestPermissionsAsync() and check whether status is 'granted' before proceeding.

import * as Notifications from 'expo-notifications';

async function requestNotificationPermission() {
  const { status } = await Notifications.requestPermissionsAsync();
  if (status !== 'granted') {
    Alert.alert(
      'Permission Denied',
      'Enable notifications in Settings to receive reminders.'
    );
    return false;
  }
  return true;
}

Setting a Default Notification Handler

Set a global notification handler with Notifications.setNotificationHandler to control how notifications behave when the app is in the foreground. Without this, notifications delivered while your app is open are silently ignored on iOS. Call it once at the module level (outside any component) so it is always active.

import * as Notifications from 'expo-notifications';

Notifications.setNotificationHandler({
  handleNotification: async () => ({
    shouldShowAlert: true,   // show banner while app is open
    shouldPlaySound: true,
    shouldSetBadge: false,
  }),
});

Scheduling a One-Time Notification

Notifications.scheduleNotificationAsync schedules a notification to be delivered at a specific time. The trigger can be a number of seconds from now, a specific Date object, or a repeating calendar trigger. The function returns a unique notification identifier that you can use later to cancel the notification if needed.

async function scheduleReminder() {
  const hasPermission = await requestNotificationPermission();
  if (!hasPermission) return;

  const id = await Notifications.scheduleNotificationAsync({
    content: {
      title: 'Daily Reminder',
      body: 'Time to check your goals for today!',
      sound: true,
      data: { screen: 'Goals' }, // custom data for handling the tap
    },
    trigger: {
      seconds: 60, // deliver in 60 seconds
    },
  });

  console.log('Notification scheduled with ID:', id);
}

Scheduling a Recurring Notification

To schedule a repeating notification — for example a daily 8 AM reminder — use a calendar trigger with a repeats: true flag. Specify the hour, minute, and optionally day-of-week to create any recurring pattern. The OS delivers the notification at the specified time and automatically reschedules it for the next occurrence.

await Notifications.scheduleNotificationAsync({
  content: {
    title: 'Good morning!',
    body: 'Your daily coding practice is waiting.',
  },
  trigger: {
    type: Notifications.SchedulableTriggerInputTypes.CALENDAR,
    hour: 8,
    minute: 0,
    repeats: true, // fires every day at 8:00 AM
  },
});

Cancelling a Scheduled Notification

Save the notification identifier returned by scheduleNotificationAsync (e.g., in state or AsyncStorage) so you can cancel it later. Call Notifications.cancelScheduledNotificationAsync(id) with the saved ID to cancel a specific notification. Use cancelAllScheduledNotificationsAsync() to cancel all pending notifications at once.

const [notifId, setNotifId] = React.useState<string | null>(null);

async function cancelReminder() {
  if (notifId) {
    await Notifications.cancelScheduledNotificationAsync(notifId);
    setNotifId(null);
    console.log('Notification cancelled');
  }
}

// Or cancel all at once:
await Notifications.cancelAllScheduledNotificationsAsync();

Handling Foreground Notifications

Use Notifications.addNotificationReceivedListener to react when a notification arrives while the app is open. This is useful for updating in-app badges, playing a custom sound, or refreshing a data feed. Always remove the listener in the useEffect cleanup to prevent memory leaks.

useEffect(() => {
  const subscription = Notifications.addNotificationReceivedListener(
    (notification) => {
      console.log('Received:', notification.request.content.title);
      const screen = notification.request.content.data?.screen;
      if (screen) setBadge(screen);
    }
  );
  return () => subscription.remove();
}, []);

Handling Notification Taps

Use Notifications.addNotificationResponseReceivedListener to handle when the user taps a notification banner. This callback fires whether the app was in the foreground, background, or closed. Use the custom data field you attached when scheduling to navigate to the correct screen in your app.

useEffect(() => {
  const subscription = Notifications.addNotificationResponseReceivedListener(
    (response) => {
      const screen = response.notification.request.content.data?.screen;
      if (screen && navigationRef.current) {
        navigationRef.current.navigate(screen);
      }
    }
  );
  return () => subscription.remove();
}, []);

Getting All Scheduled Notifications

Call Notifications.getAllScheduledNotificationsAsync() to retrieve a list of all pending scheduled notifications. This is useful for debugging, for showing a 'Reminders' management screen where users can review and delete scheduled notifications, or for preventing duplicate scheduling if the user reopens the settings screen.

async function listScheduledNotifications() {
  const scheduled = await Notifications.getAllScheduledNotificationsAsync();
  console.log('Pending notifications:', scheduled.length);
  scheduled.forEach((notif) => {
    console.log(
      notif.identifier,
      notif.content.title,
      JSON.stringify(notif.trigger)
    );
  });
}

Badges and Android Channels

On iOS, set the app badge number with Notifications.setBadgeCountAsync(count). On Android 8+, notifications must be assigned to a notification channel which controls sound, vibration, and importance. Create a channel once on app startup using Notifications.setNotificationChannelAsync and reference its ID in your notification's channelId field.

if (Platform.OS === 'android') {
  await Notifications.setNotificationChannelAsync('reminders', {
    name: 'Reminders',
    importance: Notifications.AndroidImportance.HIGH,
    vibrationPattern: [0, 250, 250, 250],
    sound: 'default',
  });
}

// Reference in notification:
await Notifications.scheduleNotificationAsync({
  content: { title: 'Reminder', channelId: 'reminders' },
  trigger: { seconds: 30 },
});

Quick Check

Test your understanding of React Native Mobile Development concepts from this lesson.

Lesson Recap

In this lesson you learned: requestPermissionsAsync must be granted before any notification can appear, scheduleNotificationAsync with a trigger delivers one-time or repeating notifications at specified times, and addNotificationResponseReceivedListener handles user taps to navigate to the right screen. Next up we explore handling permissions gracefully.

よくある質問

「ローカル通知のスケジュール設定」レッスンは無料ですか？

はい。「ローカル通知のスケジュール設定」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）、React Native Academy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。 React Native Academyコースには全4レッスンが含まれています。

「ローカル通知のスケジュール設定」で何を学びますか？

expo-notificationsをインストールして権限をリクエストし、遅延後に発火するローカル通知をスケジュールして、通知のタップで特定の画面へ移動できるようにしますブラウザで直接実行するハンズオンコードでReact Native Academy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。

React Native Academy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React Native Academy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。

「ローカル通知のスケジュール設定」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React Native Academy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React Native Academy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。

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