当应用程序在后台通过api时显示Firebase消息onReceived的通知

您需要在后台运行的服务才能捕获PUSH通知并将其显示给用户,这就是Firebase通知服务为您提供的功能.我有这个(你必须修改它,以便在出现通知时做你想做的事):

public class MyFirebaseMessagingService extends FirebaseMessagingService {

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        if (remoteMessage.getNotification().getBody() != null) {
            Log.e("FIREBASE", "Message Notification Body: " + remoteMessage.getNotification().getBody());
            sendNotification(remoteMessage);
        }
    }

    private void sendNotification(RemoteMessage remoteMessage) {
        RemoteMessage.Notification notification = remoteMessage.getNotification();
        Intent intent = new Intent(this, MainActivity.class);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent,
                PendingIntent.FLAG_ONE_SHOT);

        Uri defaultSoundUri= RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
                .setLargeIcon(BitmapFactory.decodeResource(getResources(),R.drawable.logo_gris))
                .setSmallIcon(R.drawable.logo_gris)
                .setContentTitle(notification.getTitle())
                .setContentText(notification.getBody())
                .setAutoCancel(true)
                .setSound(defaultSoundUri)
                .setContentIntent(pendingIntent);

        NotificationManager notificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

        notificationManager.notify(0, notificationBuilder.build());
    }


}