安排本地通知
安装 expo-notifications，请求权限，安排一条在延迟后触发的本地通知，并处理通知点击以导航到指定屏幕。
安排本地通知 是 CoddyKit 上的免费 React Native Academy 课时。 这是第 3 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 React Native Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 React Native Academy 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
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.
常见问题解答
「安排本地通知」课时是免费的吗？
是的 — 「安排本地通知」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 React Native Academy 课程的其余内容，请升级到 CoddyKit PRO。 React Native Academy 课程共包含 4 节课。
「安排本地通知」这节课中我会学到什么？
安装 expo-notifications，请求权限，安排一条在延迟后触发的本地通知，并处理通知点击以导航到指定屏幕。 你通过在浏览器中直接运行的动手代码来练习 React Native Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 React Native Academy 需要有经验吗？
无需任何先前经验。CoddyKit 上的 React Native Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 3 节课，共 4 节。
「安排本地通知」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 React Native Academy 课中编写并运行代码吗？
能。每节 React Native Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。