当应用处于前台时，无法接收FCM通知

Question

I am working with FCM notifications. My notifications are working perfectly when the App is in background but not able to receive a notification when the app is in foreground. I tried almost everything but not working. Notifications are not received when App is in foreground.

Manifest.xml:

       <service
        android:name=".Notification.MyFirebaseMessagingService"
        android:exported="false">
        <intent-filter>

            <action android:name="com.google.firebase.MESSAGING_EVENT" />
        </intent-filter>
    </service>

    <service android:name=".Notification.MyFirebaseInstanceIDService">
        <intent-filter>
            <action android:name="com.google.firebase.INSTANCE_ID_EVENT" />
        </intent-filter>
    </service>

Code(FirebaseMessagingService) :

           @Override
public void onMessageReceived(RemoteMessage remoteMessage) {
    Log.e(TAG, "From: " + remoteMessage.getFrom());

    if (remoteMessage == null)
        return;

    // Check if message contains a notification payload.
    if (remoteMessage.getNotification() != null) {
        Log.e(TAG, "Notification Body: " + remoteMessage.getNotification().getBody());
        handleNotification(remoteMessage.getNotification().getBody());
    }

    try {

        JSONObject json = new JSONObject(remoteMessage.getData().toString());
        handleDataMessage(json);
    } catch (Exception e) {
        Log.e(TAG, "Exception: " + e.getMessage());
    }


    Log.e(TAG, "Data Payload: " + remoteMessage.getData().toString());

}

private void handleNotification(String message) {
    if (!NotificationUtils.isAppIsInBackground(getApplicationContext())) {
        // app is in foreground, broadcast the push message
        Intent pushNotification = new Intent(Config.PUSH_NOTIFICATION);
        pushNotification.putExtra("message", message);
        LocalBroadcastManager.getInstance(this).sendBroadcast(pushNotification);

        // play notification sound
        NotificationUtils notificationUtils = new NotificationUtils(getApplicationContext());
        notificationUtils.playNotificationSound();
    } else {
        // If the app is in background, firebase itself handles the notification
    }
}

private void handleDataMessage(JSONObject json) {
    Log.e(TAG, "push json: " + json.toString());

    try {
        JSONObject data = json.getJSONObject("data");
        String title = data.getString("title");
        String message = data.getString("body");
        boolean isBackground = data.getBoolean("is_background");
        String imageUrl = data.getString("image");
        String timestamp = data.getString("timestamp");
        JSONObject payload = data.getJSONObject("payload");

        Log.e(TAG, "title: " + title);
        Log.e(TAG, "message: " + message);
        Log.e(TAG, "isBackground: " + isBackground);
        Log.e(TAG, "payload: " + payload.toString());
        Log.e(TAG, "imageUrl: " + imageUrl);
        Log.e(TAG, "timestamp: " + timestamp);


        if (!NotificationUtils.isAppIsInBackground(getApplicationContext())) {
            // app is in foreground, broadcast the push message
            Intent pushNotification = new Intent(Config.PUSH_NOTIFICATION);
            pushNotification.putExtra("message", message);
            LocalBroadcastManager.getInstance(this).sendBroadcast(pushNotification);

            // play notification sound
            NotificationUtils notificationUtils = new NotificationUtils(getApplicationContext());
            notificationUtils.showNotificationMessage("iGrab", message, timestamp, pushNotification);
            notificationUtils.playNotificationSound();


        } else {
            // app is in background, show the notification in notification tray
            Intent resultIntent = new Intent(getApplicationContext(), Splash.class);
            resultIntent.putExtra("message", message);

            // check for image attachment
            if (TextUtils.isEmpty(imageUrl)) {

                showNotificationMessage(getApplicationContext(), title, message, timestamp, resultIntent);
            } else {
                // image is present, show notification with image
                showNotificationMessageWithBigImage(getApplicationContext(), title, message, timestamp, resultIntent, imageUrl);
            }
        }
    } catch (JSONException e) {
        Log.e(TAG, "Json Exception: " + e.getMessage());
    } catch (Exception e) {
        Log.e(TAG, "Exception: " + e.getMessage());
    }
}

Answer 1

FCM support two types of messages:

• Notification message
• Data message

If server send Notification message then it automatically displays a notification on system tray.

Use notification messages when you want FCM to handle displaying a notification on your client app's behalf. Use data messages when you want to process the messages on your client app.

FCM can send a notification message including an optional data payload. In such cases, FCM handles displaying the notification payload, and the client app handles the data payload.

And the point is in your case:

Notification messages are delivered to the notification tray when the app is in the background. For apps in the foreground, messages are handled by a callback function.

https://firebase.google.com/docs/cloud-messaging/concept-options