我有一个安装在Android和iOS设备上的Expo应用程序。这些应用程序使用Firebase作为后端。我还在Reactjs中创建了一个 Jmeter 板，也使用相同的Firebase作为后端。
我想在Reactjs Dashboard上执行某些事件时向特定用户发送通知。例如：我将order_status从“pending”更改为“delivered”，然后firebase事件更改firebase集合中该用户的order_status，因此我希望用户知道其订单已被分派。
如何在Android和iOS上实现这一点？
如何在Android和iOS上实现这一点？

解决方案：
用于设置接收通知的应用端代码：

const [expoPushToken, setExpoPushToken] = useState('');
  const [notification, setNotification] = useState(false);
  const notificationListener = useRef();
  const responseListener = useRef();


 async function sendPushNotification(expoPushToken) {
    const message = {
      to: expoPushToken,
      sound: 'default',
      title: 'Original Title',
      body: 'And here is the body!',
      data: { someData: 'goes here' },
    };

    console.log(expoPushToken);

    await fetch('https://exp.host/--/api/v2/push/send', {
      method: 'POST',
      headers: {
        Accept: 'application/json',
        'Accept-encoding': 'gzip, deflate',
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(message),
    });
  }

  async function registerForPushNotificationsAsync() {
    let token;
    if (Device.isDevice) {
      const { status: existingStatus } = await Notifications.getPermissionsAsync();
      let finalStatus = existingStatus;
      if (existingStatus !== 'granted') {
        const { status } = await Notifications.requestPermissionsAsync();
        finalStatus = status;
      }
      if (finalStatus !== 'granted') {
        alert('Failed to get push token for push notification!');
        return;
      }
      token = (await Notifications.getExpoPushTokenAsync()).data;
      console.log(token);
    } else {
      alert('Must use physical device for Push Notifications');
    }

    if (Platform.OS === 'android') {
      Notifications.setNotificationChannelAsync('default', {
        name: 'default',
        importance: Notifications.AndroidImportance.MAX,
        vibrationPattern: [0, 250, 250, 250],
        lightColor: '#FF231F7C',
      });
    }

    return token;
  }


useEffect(() => {
    registerForPushNotificationsAsync().then(token => setExpoPushToken(token));

    // This listener is fired whenever a notification is received while the app is foregrounded
    notificationListener.current = Notifications.addNotificationReceivedListener(notification => {
      setNotification(notification);
    });

    // This listener is fired whenever a user taps on or interacts with a notification (works when app is foregrounded, backgrounded, or killed)
    responseListener.current = Notifications.addNotificationResponseReceivedListener(response => {
      console.log(response);
    });

    return () => {
      Notifications.removeNotificationSubscription(notificationListener.current);
      Notifications.removeNotificationSubscription(responseListener.current);
    };
  }, []);

//在导出App函数外编写以下代码

Notifications.setNotificationHandler({
  handleNotification: async () => ({
    shouldShowAlert: true,
    shouldPlaySound: false,
    shouldSetBadge: false,
  }),
});

• 您可能需要使用以下方式安装Expo-notification：
  npx expo安装expo通知

从上面的代码中，你可以得到push令牌，首先你可以手动使用它来测试通知，然后你最终可以将所有用户的设备push令牌存储在某个firebase DB或自定义DB中。

服务器端代码：

• 请先安装此库npm i node-fetch
• 推送令牌如下所示：指数推送令牌[KA2CcEFollWMq_9TmIddctr]

import fetch from "node-fetch";

  async function sendPushNotification(expoPushToken) {
      const android = "pushToken";
      const ios = "pushToken";
      const message = {
          to: ios,
          sound: 'default',
          title: 'Original Title',
          body: 'And here is the body!',
          data: { someData: 'goes here' },
      };


   await fetch('https://exp.host/--/api/v2/push/send', {
          method: 'POST',
          headers: {
              Accept: 'application/json',
              'Accept-encoding': 'gzip, deflate',
              'Content-Type': 'application/json',
          },
          body: JSON.stringify(message),
      });
  }

在结束时调用该函数sendPushNotification（）;