Sample methods for logging received push notifications on Android.

AppActivity.kt

package com.example.ui

import android.app.Activity
import android.content.Intent
import android.os.Bundle
import com.example.util.toKeyValueString
import timber.log.Timber

class AppActivity : Activity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        // ...
        handleIntent(intent)
    }

    override fun onNewIntent(intent: Intent?) {
        super.onNewIntent(intent)
        handleIntent(intent)
    }

    private fun handleIntent(intent: Intent?) {
        // Push notification data payload is delivered in the extras of the intent of your launcher Activity.
        Timber.d("New intent: $intent\nData: ${intent?.data}\nExtras: ${intent?.extras?.toKeyValueString()}")
        // ...
    }
}

BundleExtensions.kt

package com.example.util

import android.os.Bundle

fun Bundle.toKeyValueString(): String =
    keySet()
        .fold(StringBuilder("{\n")) { sb, key -> sb.append("\t$key: ${get(key)}\n") }
        .append("}\n")
        .toString()

Logcat.log

D/PushNotificationService: Message received:
    {
    	messageId: 0:1570354827026078%90b1c65594b1c645
    	messageType: null
    	from: 736731615502
    	to: null
    	sendTime: 1572353820021
    	ttl: 2419200
    	priority: 2
    	originalPriority: 2
    	collapseKey: com.example
    	notification: {
    		title: FCM push notification
    		titleLocalizationKey: null
    		titleLocalizationArgs: null
    		body: Hello, world!
    		bodyLocalizationKey: null
    		bodyLocalizationArgs: null
    		clickAction: null
    		sound: null
    		icon: null
    		color: null
    		tag: null
    		channelId: null
    		defaultLightSettings: false
    		defaultSound: false
    		defaultVibrateSettings: false
    		eventTime: null
    		imageUrl: null
    		lightSettings: null
    		link: null
    		localOnly: false
    		notificationCount: null
    		notificationPriority: null
    		sticky: false
    		ticker: null
    		vibrateTimings: null
    		visibility: null
    	}
    	"data": {
    		key1: value1
    		key2: value2
    	}
    }
D/AppActivity: New intent: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x14000000 pkg=com.example cmp=com.example/com.example.ui.AppActivity (has extras) }
    Data: null
    Extras: {
    	google.delivered_priority: normal
    	google.sent_time: 1572353828002
    	google.ttl: 2419200
    	google.original_priority: normal
    	from: 736731615502
    	key1: value1
    	key2: value2
    	google.message_id: 0:1570354828704699%90b1c65594b1c645
    	collapse_key: com.example
    }

PushNotificationService.kt

package com.example.system.push

import com.google.firebase.messaging.FirebaseMessagingService
import com.google.firebase.messaging.RemoteMessage
import timber.log.Timber
import java.util.*

class PushNotificationService : FirebaseMessagingService() {

    override fun onMessageReceived(remoteMessage: RemoteMessage) {
        super.onMessageReceived(remoteMessage)
        Timber.d("Message received:\n${remoteMessage.toKeyValueString()}")
        // ...
    }

    override fun onNewToken(newToken: String) {
        super.onNewToken(newToken)
        sendRegistrationTokenToServer(newToken)
    }
    
    private fun sendRegistrationTokenToServer(newToken: String) {
        Timber.d("Token: $newToken")
        // ...
    }

    private fun RemoteMessage?.toKeyValueString(): String {

        if (this == null) return "null"

        val sb = StringBuilder("{\n")

        sb.append("\tmessageId: $messageId\n")
        sb.append("\tmessageType: $messageType\n")
        sb.append("\tfrom: $from\n")
        sb.append("\tto: $to\n")
        sb.append("\tsendTime: $sentTime\n")
        sb.append("\tttl: $ttl\n")
        sb.append("\tpriority: $priority\n")
        sb.append("\toriginalPriority: $originalPriority\n")
        sb.append("\tcollapseKey: $collapseKey\n")

        val notification = notification
        if (notification != null) {
            sb.append("\tnotification: {\n")
            sb.append("\t\ttitle: ${notification.title}\n")
            sb.append("\t\ttitleLocalizationKey: ${notification.titleLocalizationKey}\n")
            sb.append("\t\ttitleLocalizationArgs: ${Arrays.toString(notification.titleLocalizationArgs)}\n")
            sb.append("\t\tbody: ${notification.body}\n")
            sb.append("\t\tbodyLocalizationKey: ${notification.bodyLocalizationKey}\n")
            sb.append("\t\tbodyLocalizationArgs: ${Arrays.toString(notification.bodyLocalizationArgs)}\n")
            sb.append("\t\tclickAction: ${notification.clickAction}\n")
            sb.append("\t\tsound: ${notification.sound}\n")
            sb.append("\t\ticon: ${notification.icon}\n")
            sb.append("\t\tcolor: ${notification.color}\n")
            sb.append("\t\ttag: ${notification.tag}\n")
            sb.append("\t\tchannelId: ${notification.channelId}\n")
            sb.append("\t\tdefaultLightSettings: ${notification.defaultLightSettings}\n")
            sb.append("\t\tdefaultSound: ${notification.defaultSound}\n")
            sb.append("\t\tdefaultVibrateSettings: ${notification.defaultVibrateSettings}\n")
            sb.append("\t\teventTime: ${notification.eventTime}\n")
            sb.append("\t\timageUrl: ${notification.imageUrl}\n")
            sb.append("\t\tlightSettings: ${Arrays.toString(notification.lightSettings)}\n")
            sb.append("\t\tlink: ${notification.link}\n")
            sb.append("\t\tlocalOnly: ${notification.localOnly}\n")
            sb.append("\t\tnotificationCount: ${notification.notificationCount}\n")
            sb.append("\t\tnotificationPriority: ${notification.notificationPriority}\n")
            sb.append("\t\tsticky: ${notification.sticky}\n")
            sb.append("\t\tticker: ${notification.ticker}\n")
            sb.append("\t\tvibrateTimings: ${Arrays.toString(notification.vibrateTimings)}\n")
            sb.append("\t\tvisibility: ${notification.visibility}\n")
            sb.append("\t}\n")
        } else {
            sb.append("\tnotification: null\n")
        }

        sb.append("\t\"data\": {\n")
        for ((key, value) in data) {
            sb.append("\t\t$key: $value\n")
        }
        sb.append("\t}\n")

        sb.append("}\n")
        return sb.toString()
    }
}