应用未运行时未显示通知徽标（FCM）

Question

So i have implemented FCM for notifications. So, we can also send some data along with an notification using Firebase Cloud Messaging. Here i have created a channel and registed the device to a "general" topic.

Here is my code :

package com.femindharamshi.fcmtrial;

import android.app.NotificationManager;
import android.content.Context;
import android.content.SharedPreferences;
import android.support.v4.app.NotificationCompat;
import android.support.v4.app.NotificationManagerCompat;
import android.util.Log;

import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;

import java.util.Map;

public class MyFirebaseMessagingService extends FirebaseMessagingService {

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);
        Map m = remoteMessage.getData();
        showNotification(remoteMessage.getNotification().getTitle(), remoteMessage.getNotification().getBody(), m);

        Class me = remoteMessage.getClass();
        Log.d("MessageDateRecieved", ""+me.toString());

    }

    public void showNotification(String title, String message, Map m) {

        NotificationCompat.Builder builder = new NotificationCompat.Builder(this, "MyNotifications")
                .setContentTitle(title)
                .setSmallIcon(R.drawable.small_logo)
                .setAutoCancel(true)
                .setContentText(message);

        NotificationManagerCompat manager = NotificationManagerCompat.from(this);
        manager.notify(999, builder.build());

    }
}

Now i am having following 2 issues :

1. When the app is not running/killed, then the notification logo (R.drawable.small_logo) residing in my res/drawable folder is not shown instead a gray circle is shown. How do i solve this problem.
2. If i pass data through this message i can capture it in a Map. Now imaging the app is not running and i want to save this data in SharedPreferences, then how is it possible ?

Answer 1

Icon shown for notification when your app is not running can only be monochrome, so icon with transparency should be used as a shape and color for it can be provided separately. It looks like these lines inside application tag in AndroidManifest.xml .

    <meta-data
        android:name="com.google.firebase.messaging.default_notification_icon"
        android:resource="@drawable/icon_notification_shape" />
    <meta-data
        android:name="com.google.firebase.messaging.default_notification_color"
        android:resource="@color/color_notification" />