Question

未定义不是对象（评估'_pushtokenManager.default.getDevicePushTokenAsync [react Native Expo]

2020-07-06

5345

android react-native push-notification expo

无法使用 expo-notifications api 上的 getExpoPushTokenAsync() 函数获取令牌。下面的函数与 Expo 文档完全相同：

import Constants from "expo-constants";
import * as Notifications from "expo-notifications";
import * as Permissions from "expo-permissions";

async function registerForPushNotificationsAsync() {
    let token;
    if (Constants.isDevice) {
    const { status: existingStatus } = await Permissions.getAsync(Permissions.NOTIFICATIONS);
    let finalStatus = existingStatus;
    if (existingStatus !== 'granted') {
        const { status } = await Permissions.askAsync(Permissions.NOTIFICATIONS);
        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;
}

Expo：~37.0.3 App.json：

"expo": {
        "android": {
          "useNextNotificationsApi": true
        }
      }

似乎在调用该函数时，收到了下一个警告：

[Unhandled promise rejection: TypeError: undefined is not an object (evaluating '_PushTokenManager.default.getDevicePushTokenAsync')]

Answer 1

确保从“expo”导入 {Notifications}，而不是从“expo-notifications”导入。遇到了同样的问题，但后来尝试从“expo”导入，成功了。查看此图片

Answer 2

确保您处于托管工作流中，如果您处于裸工作流中，则应指定 { experienceId }。

来自文档的代码示例：

import Constants from 'expo-constants';
import * as Notifications from 'expo-notifications';

export async function registerForPushNotificationsAsync(userId: string) {
  let experienceId = undefined;
  if (!Constants.manifest) {
    // Absence of the manifest means we're in bare workflow
    experienceId = '@username/example';
  }
  const expoPushToken = await Notifications.getExpoPushTokenAsync({
    experienceId,
  });
  await fetch('https://example.com/', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({
      userId,
      expoPushToken,
    }),
  });
}

experienceId (string) - 应将令牌归因于的体验的 ID。默认为 expo-constants 公开的 Constants.manifest.id。在裸工作流中，您必须提供一个采用 @username/projectSlug 形状的值，其中 username 是与项目关联的 Expo 帐户，projectSlug 是来自 app.json 的 slug

更多信息： https://docs.expo.io/versions/latest/sdk/notifications/#dailytriggerinput

Answer 3

我有这个错误，因为我没有登录Expo（使用Expo Client）。

jakobinn

2020-11-03