当应用程序未运行时，在 Android 手机上接收 FCM 数据通知

Question

I am sending pure FCM data notifications to an Android client which are end-to-end encrypted. The android app decrypts the data notification payload and creates a local notification from the encrypted data. This works fine as long as the app is running in the foreground or in the background: the notification payload is received, decrypted and is even shown on the lock screen, but only as long as the app is running. I also looked at the message priority and set this to "high" in my application server that sends to FCM, both in the AndroidConfig member of the notification message and in the data field, but to no avail. What is the correct way to send a data message to an android device where the corresponding app is currently not running? Is this possible at all?

My server code (in golang) looks something like this, it hopes the fragment makes sense:

app, err := firebase.NewApp(context.Background(), nil)
if err != nil {
    logger.Info("Error initializing app: %v\n", err)
    os.Exit(-536870136) /// -536870136 = 0xE0000308 is ERR_INOTE_FCM_FAILED_APP_INITIALIZE
}

// Obtain a messaging.Client from the App.
ctx := context.Background()
client, err := app.Messaging(ctx)
if err != nil {
    logger.Info("Error getting Messaging client: %v\n", err)
    os.Exit(-536870137) /// -536870137 = 0xE0000307 is ERR_INOTE_FCM_FAILED_GET_MESSAGING_CLIENT
}

message := &messaging.Message{
    Data: map[string]string{
        "NotificationType": "Push",
        "E2E":              strEncrypted,
        "IV":               strIV,
        "Key":              strSessionKey,
        "Signature":        strSignature,
    },
    Token: registrationToken,
}

// Send a message to the device corresponding to the provided
// registration token.
response, err := client.Send(ctx, message)
if err != nil {
    logger.Info(err)
    os.Exit(-536870138) /// -536870138 = 0xE0000306 is ERR_INOTE_FCM_FAILED_SEND
}

Any help appreciated,

-- Stefan

Answer 1

You are doing great and absolutely right It android OS behaviour when app in background you are no longer to handle message

You need to add default intent filter in android manifest file and if notifications comes when app in background. So after clicking on fcm you will launch default activity. Here you can add your logics