Android 在Firebase中应用程序处于后台时如何处理通知

这是我的舱单

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

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

据

在后台应用程序中处理消息

当你的应用程序在后台时，Android会发出通知 将邮件发送到系统托盘。用户点击通知打开 默认情况下，应用程序启动器

这包括同时包含通知和数据的消息 有效载荷。在这些情况下，通知会发送到设备的 系统托盘，数据有效负载在 您的启动器活动的意图

如果要打开应用程序并执行特定操作，请设置 单击通知负载中的\u操作并将其映射到意图 筛选要启动的活动。例如，设置 单击\u操作打开\u活动\u 1以触发类似 以下:

：

您无法使用Firebase控制台设置单击操作负载。您可以尝试使用curl命令或自定义http服务器进行测试

curl --header "Authorization: key=<YOUR_KEY_GOES_HERE>" 
     --header Content-Type:"application/json" https://fcm.googleapis.com/fcm/send  
     -d "{\"to\":\"/topics/news\",\"notification\": 
         {\"title\": \"Click Action Message\",\"text\": \"Sample message\",
            \"click_action\":\"OPEN_ACTIVITY_1\"}}"

curl--header“Authorization:key=”
--标题内容类型：“应用程序/json”https://fcm.googleapis.com/fcm/send  
-d“{\”至\”：“/topics/news\”，“notification\”：
{\'title\'：\'Click Action Message\'，\'text\'：\'Sample Message\'，
\“单击\u action\”：\“打开\u活动\u 1\”}”
1。为什么会这样？
FCM（Firebase云消息传递）中有两种类型的消息：

显示消息：这些消息仅在应用程序位于前台时触发
onMessageReceived（）
回调
数据消息：如果您的应用程序位于前台/后台/死机中，这些消息会触发
onMessageReceived（）
回调

注意：Firebase团队尚未开发一个用户界面，用于向用户发送
数据消息
你的设备，还没有。您应该使用您的服务器发送此类型





2.如何？
要实现这一点，您必须对以下URL执行
POST
请求：

POST

标题

键：
内容类型
，值：
应用程序/json
键：
授权
，值：
键=

身体使用主题
或者如果您想将其发送到特定设备


注意：确保您没有添加JSON密钥
通知

注意：要获取您的服务器密钥，您可以在firebase控制台中找到它：
您的项目->设置->项目设置->云消息->服务器密钥

3.如何处理推送通知消息？
以下是您处理收到的消息的方式：

@Override
public void onMessageReceived(RemoteMessage remoteMessage) { 
     Map<String, String> data = remoteMessage.getData();
     String myCustomKey = data.get("my_custom_key");

     // Manage data
}

@覆盖
收到的消息（RemoteMessage RemoteMessage）上的公共无效{
Map data=remoteMessage.getData（）；
字符串myCustomKey=data.get（“my_custom_key”）；
//管理数据
}
使firebase库在以下情况下调用您的onMessageReceived（）

前台应用程序
后台应用程序
应用程序已被删除
您不能将JSON键“通知”放在对firebase API的请求中，而应使用“数据”，见下文

当您的应用程序处于后台或被终止时，以下消息将不会调用您的onMessageReceived（），并且您无法自定义通知

{
   "to": "/topics/journal",
   "notification": {
       "title" : "title",
       "text": "data!",
       "icon": "ic_notification"
    }
}

但是，使用它会起作用

{
  "to": "/topics/dev_journal",
   "data": {
       "text":"text",
       "title":"",
       "line1":"Journal",
       "line2":"刊物"
   }
} 

基本上，消息在参数RemoteMessage中作为映射与数据对象一起发送，然后您可以在onMessageReceived中管理通知，如这里的代码段所示

@Override
public void onMessageReceived(RemoteMessage remoteMessage) { 
     Map<String, String> data = remoteMessage.getData();

     //you can get your text message here.
     String text= data.get("text");


     NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
        // optional, this is to make beautiful icon
             .setLargeIcon(BitmapFactory.decodeResource(
                                    getResources(), R.mipmap.ic_launcher))  
        .setSmallIcon(smallIcon)  //mandatory
      .......
    /*You can read more on notification here:
    https://developer.android.com/training/notify-user/build-notification.html
    https://www.youtube.com/watch?v=-iog_fmm6mE
    */
}

@覆盖
收到的消息（RemoteMessage RemoteMessage）上的公共无效{
Map data=remoteMessage.getData（）；
//你可以在这里收到你的短信。
String text=data.get（“text”）；
NotificationCompat.Builder notificationBuilder=新建NotificationCompat.Builder（此）
//可选，这是为了制作漂亮的图标
.setLargeIcon（BitmapFactory.decodeResource(
getResources（），R.mipmap.ic_启动器）
.setSmallIcon（smallIcon）//必须
.......
/*您可以在此处阅读有关通知的更多信息：
https://developer.android.com/training/notify-user/build-notification.html
https://www.youtube.com/watch?v=-iog_fmm6mE
*/
}
根据中的firebase文档，有两种类型的有效载荷：

数据

此参数指定消息有效负载的自定义键值对。
客户端应用程序负责处理数据消息。数据消息只有自定义键值对


通知

此参数指定通知有效负载的预定义的、用户可见的键值对。FCM代表客户端应用程序自动向最终用户设备显示消息。通知消息具有一组预定义的用户可见键


当您在前台时，您可以使用onMessageReceived（）获取FCM内部的数据，您可以从数据有效负载获取数据

data = remoteMessage.getData();
String customData = (String) data.get("customData");

{
  "notification": {
        "title" : "title",
        "body"  : "body text",
        "icon"  : "ic_notification",
        "click_action" : "OPEN_ACTIVITY_1"
       }
}

当您在后台时，FCM将根据通知有效负载中的信息在系统托盘中显示通知。用于系统托盘上通知的标题、消息和图标来自通知有效负载

data = remoteMessage.getData();
String customData = (String) data.get("customData");

{
  "notification": {
        "title" : "title",
        "body"  : "body text",
        "icon"  : "ic_notification",
        "click_action" : "OPEN_ACTIVITY_1"
       }
}

当您希望在后台应用程序时在系统托盘上自动显示通知时，将使用此通知有效负载。
要在应用程序处于后台时获取通知数据，您应该在通知负载中添加单击操作

data = remoteMessage.getData();
String customData = (String) data.get("customData");

{
  "notification": {
        "title" : "title",
        "body"  : "body text",
        "icon"  : "ic_notification",
        "click_action" : "OPEN_ACTIVITY_1"
       }
}

如果您想[在后台]打开应用程序并执行特定操作，请在通知负载中设置click_action，并将其映射到Activ中的意图过滤器
<intent-filter>
  <action android:name="OPEN_ACTIVITY_1" />
  <category android:name="android.intent.category.DEFAULT" />
</intent-filter>

Bundle b = getIntent().getExtras();
String someData = b.getString("someData");

{
  "to": "FCM registration ID",
  "notification": {
    "title" : "title",
    "body"  : "body text",
    "icon"  : "ic_notification",
    "click_action" : "OPEN_ACTIVITY_1"
   },
   "data": {
     "someData"  : "This is some data",
     "someData2" : "etc"
   }
}

import android.content.Context
import android.content.Intent
import android.util.Log
import androidx.legacy.content.WakefulBroadcastReceiver
import com.google.firebase.messaging.RemoteMessage

class FirebaseBroadcastReceiver : WakefulBroadcastReceiver() {

    val TAG: String = FirebaseBroadcastReceiver::class.java.simpleName

    override fun onReceive(context: Context, intent: Intent) {

        val dataBundle = intent.extras
        if (dataBundle != null)
            for (key in dataBundle.keySet()) {
                Log.d(TAG, "dataBundle: " + key + " : " + dataBundle.get(key))
            }
        val remoteMessage = RemoteMessage(dataBundle)
        }
    }

<receiver
      android:name="MY_PACKAGE_NAME.FirebaseBroadcastReceiver"
      android:exported="true"
      android:permission="com.google.android.c2dm.permission.SEND">
        <intent-filter>
            <action android:name="com.google.android.c2dm.intent.RECEIVE" />
        </intent-filter>
</receiver>

{
  "data":{
    "id": 1,
    "missedRequests": 5
    "addAnyDataHere": 123
  },
  "to": "fhiT7evmZk8:APA91bFJq7Tkly4BtLRXdYvqHno2vHCRkzpJT8QZy0TlIGs......"
}

Object obj = message.getData().get("id");
        if (obj != null) {
            int id = Integer.valueOf(obj.toString());
        }

onMessageReceived()

onMessageReceived()

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState, R.layout.activity_splash);

    if (getIntent().getExtras() != null && getIntent().getExtras().containsKey("PACKAGE_NAME")) {

        // do what you want

        // and this for killing app if we dont want to start
        android.os.Process.killProcess(android.os.Process.myPid());

    } else {

        //continue to app
    }
}

android.os.Process.killProcess(android.os.Process.myPid());

{ "data": {
    "image": "https://static.pexels.com/photos/4825/red-love-romantic-flowers.jpg",
    "message": "Firebase Push Message Using API"
    "AnotherActivity": "True"
     },
  "to" : "device id Or Device token"
}

{
    "to" : "/topics/topic_name",
    "data": {
    "key1" : "value1",
    "key2" : "value2",
    }
}

{
    "registration_ids" : "[{"id"},{id1}]",
    "data": {
    "key1" : "value1",
    "key2" : "value2",
     }
}

@Override
public void onMessageReceived(RemoteMessage remoteMessage) { 
     Map<String, String> data = remoteMessage.getData();
     String value1 = data.get("key1");
     String value2 = data.get("key2");
}

<activity android:name=".MainActivity">
      <intent-filter>
           <action android:name=".MainActivity" />
           <category android:name="android.intent.category.DEFAULT" />
      </intent-filter>
</activity>

{ 
 "notification" : {
        "click_action" : ".MainActivity", 
        "body" : "new Symulti update !", 
        "title" : "new Symulti update !", 
        "icon" : "ic_notif_symulti" }, 
 "data": { ... },
 "to" : "c9Vaa3ReGdk:APA91bH-AuXgg3lDN2WMcBrNhJZoFtYF9" }

"click_action" : ".MainActivity"

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //get notification data info
    Bundle bundle = getIntent().getExtras();
    if (bundle != null) {
       //bundle must contain all info sent in "data" field of the notification
    }
}

{
  "to": "FCM registration ID",
  "notification": {
    "title" : "title",
    "body"  : "body text",
    "icon"  : "ic_notification"
   },
   "data": {
     "someData"  : "This is some data",
     "someData2" : "etc"
   }
}

<activity android:name=".MainActivity">
        <intent-filter>
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
</activity>

Intent intent = getIntent();
if (intent != null && intent.getExtras() != null) {
    Bundle extras = intent.getExtras();
    String someData= extras.getString("someData");
    String someData2 = extras.getString("someData2");
}

@Override
public void onMessageReceived(RemoteMessage remoteMessage) {

}

compile 'com.google.firebase:firebase-messaging:10.2.1'

@Override
public void handleIntent(Intent intent) {
    super.handleIntent(intent);

    // you can get ur data here 
    //intent.getExtras().get("your_data_key") 


}

if(getIntent().getExtras() != null && getIntent().getExtras().get("your_data_key") != null) {
String strNotificaiton = getIntent().getExtras().get("your_data_key").toString();

{
    "notification": {
        "body": "Cool offers. Get them before expiring!",
        "title": "Flat 80% discount",
        "icon": "appicon",
        "click_action": "activity name" //optional if required.....
    },
    "data": {
        "product_id": 11,
        "product_details": "details.....",
        "other_info": "......."
    }
}

"data": {
    "user_name": "arefin sajib",
    "value": "user name notification"
  }

    if(getIntent()!=null){
            Bundle bundle = getIntent().getExtras();
            if (bundle != null) {
                try {
                   JSONObject object = new JSONObject(bundle.getStringExtra("data"));
String user_name = object.optString("user_name");

                } catch (JSONException e) {
                    e.printStackTrace();
                }


            }
        }

 dependencies {
        compile 'com.google.firebase:firebase-core:11.2.0'
        compile 'com.github.erdalceylan:com-google-firebase-messaging:v1-11.2.0'
    }

@WorkerThread
public void onMessageReceived(RemoteMessage var1) {
  //your app is in background or foreground all time calling
}

<?php
$url = "https://fcm.googleapis.com/fcm/send";
$token = "C-l6T_a7HouUK****";
$serverKey = "AAAAaOcKS00:********";
define( 'API_ACCESS_KEY', $serverKey );
$registrationIds = array($token);
// prep the bundle

$msg = array

(
 'message'  => 'here is a message. message',
 'title'        => 'This is a title. title',
 'subtitle' => 'This is a subtitle. subtitle',
 'tickerText'   => 'Ticker text here...Ticker text here...Ticker text 
 here',
 'vibrate'  => 1,
 'sound'        => 1,
 'largeIcon'    => 'large_icon',
 'smallIcon'    => 'small_icon'

);

$fields = array

(
  'registration_ids'    => $registrationIds,
  'data'            => $msg

);
$headers = array

(
  'Authorization: key=' . API_ACCESS_KEY,
 'Content-Type: application/json'

);


$ch = curl_init();

curl_setopt( $ch,CURLOPT_URL, 'https://android.googleapis.com/gcm/send' 
);

curl_setopt( $ch,CURLOPT_POST, true );

curl_setopt( $ch,CURLOPT_HTTPHEADER, $headers );

curl_setopt( $ch,CURLOPT_RETURNTRANSFER, true );

curl_setopt( $ch,CURLOPT_SSL_VERIFYPEER, false );

curl_setopt( $ch,CURLOPT_POSTFIELDS, json_encode( $fields ) );

$result = curl_exec($ch );

curl_close( $ch );

echo $result;

?>

public class MyFirebaseMessagingService extends FirebaseMessagingService     {

  private static final String TAG = "MyFirebaseMsgService";

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

    // Check if message contains a data payload.
    if (remoteMessage.getData().size() > 0) {
        Log.d(TAG, "Message data payload: " + remoteMessage.getData());

      sendNotification(remoteMessage.getData().get("message"));
     }
   // Check if message contains a notification payload.
    else if (remoteMessage.getNotification() != null) {
        Log.d(TAG, "Message Notification Body: " + remoteMessage.getNotification().getBody());
    sendNotification(remoteMessage.getNotification().getBody());
    }


}
   private void sendNotification(String messageBody) {
    Intent intent = new Intent(this, Notify.class).putExtra("msg",messageBody);
    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    PendingIntent pendingIntent = PendingIntent.getActivity(this, 0 /* Request code */, intent,
            PendingIntent.FLAG_ONE_SHOT);

    String channelId = "idddd";
    Uri defaultSoundUri= RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
    NotificationCompat.Builder notificationBuilder =
            new NotificationCompat.Builder(MyFirebaseMessagingService.this)
                    .setSmallIcon(R.mipmap.ic_launcher)
                    .setContentTitle("FCM Message")
                    .setContentText(messageBody)
                    .setAutoCancel(true)
                    .setSound(defaultSoundUri)
                    .setContentIntent(pendingIntent);

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

    notificationManager.notify(0 /* ID of notification */, notificationBuilder.build());
}
}

const message = {
    token: token_id,   // obtain device token id by querying data in firebase
    data: {
       title: "my_custom_title",
       body:  "my_custom_body_message"
       }
    }


return admin.messaging().send(message).then(response => {
    // handle response
});

if (data != null) {
  Log.d(TAG, "data title is: " + data.get("title");
  Log.d(TAG, "data body is: " + data.get("body");
}

// build notification using the body, title, and whatever else you want.

//Data should come in this format from the notification
{
  "to": "/xyz/Notifications",
  "data": {
      "key1": "title notification",
      "key2": "description notification"
  }
}

  @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);
      String key1Data = remoteMessage.getData().get("key1");
      // use key1Data to according to your need
    }

"data":    "image": "",    "message": "Firebase Push Message Using API", 

  public void onMessageReceived(RemoteMessage remoteMessage)
    if (remoteMessage.getData().size() > 0) 
    Log.d(TAG, "Message data payload: " + remoteMessage.getData());      

POST: https://fcm.googleapis.com/v1/projects/YOUR_FIREBASEDB_ID/messages:send

Key: Content-Type, Value: application/json

Bearer YOUR_TOKEN 

{
   "message":{
    "topic" : "xxx",
    "data" : {
         "body" : "This is a Firebase Cloud Messaging Topic Message!",
         "title" : "FCM Message"
          }
      }
 }

var PROJECT_ID = 'YOUR_PROJECT_ID';
var HOST = 'fcm.googleapis.com';
var PATH = '/v1/projects/' + PROJECT_ID + '/messages:send';
var MESSAGING_SCOPE = 'https://www.googleapis.com/auth/firebase.messaging';
var SCOPES = [MESSAGING_SCOPE];

  router.get('/', function(req, res, next) {
      res.render('index', { title: 'Express' });
      getAccessToken().then(function(accessToken) {
        console.log("TOKEN: "+accessToken)
      })

    });

function getAccessToken() {
return new Promise(function(resolve, reject) {
    var key = require('./YOUR_DOWNLOADED_JSON_FILE.json');
    var jwtClient = new google.auth.JWT(
        key.client_email,
        null,
        key.private_key,
        SCOPES,
        null
    );
    jwtClient.authorize(function(err, tokens) {
        if (err) {
            reject(err);
            return;
        }
        resolve(tokens.access_token);
    });
});
}

@Override
public void onNewToken(String token) {
    Log.d(TAG, "Refreshed token: " + token);

}

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

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

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

    <meta-data
        android:name="com.google.firebase.messaging.default_notification_channel_id"
        android:value="@string/push_channel" />

 "data": {
"message": "2",
"title": "1",
"pushType" : "banner",
"bannerLink": "http://www.google.com",
"image" : "https://www.google.com/images/branding/googlelogo/1x/googlelogo_color_272x92dp.png"}

        Bundle extras = intent.getExtras();
        String bannerLink = extras.getString("bannerLink");
        ...
        String channelId = extras.getString("channelId");

<activity
    android:name=".MainActivity"
    android:label="@string/app_name"
    android:largeHeap="true"
    android:screenOrientation="portrait"
    android:launchMode="singleTop">
    <intent-filter>
        <action android:name=".MainActivity" />
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
        <category android:name="android.intent.category.DEFAULT" />
    </intent-filter>
</activity>

Intent i = getIntent();
Bundle extras = i.getExtras();
if (extras != null) {
    for (String key : extras.keySet()) {
        Object value = extras.get(key);
        Log.d(Application.APPTAG, "Extras received at onCreate:  Key: " + key + " Value: " + value);
    }
    String title = extras.getString("title");
    String message = extras.getString("body");
    if (message!=null && message.length()>0) {
        getIntent().removeExtra("body");
        showNotificationInADialog(title, message);
    }
}

@Override
public void onNewIntent(Intent intent){
    //called when a new intent for this class is created.
    // The main case is when the app was in background, a notification arrives to the tray, and the user touches the notification

    super.onNewIntent(intent);

    Log.d(Application.APPTAG, "onNewIntent - starting");
    Bundle extras = intent.getExtras();
    if (extras != null) {
        for (String key : extras.keySet()) {
            Object value = extras.get(key);
            Log.d(Application.APPTAG, "Extras received at onNewIntent:  Key: " + key + " Value: " + value);
        }
        String title = extras.getString("title");
        String message = extras.getString("body");
        if (message!=null && message.length()>0) {
            getIntent().removeExtra("body");
            showNotificationInADialog(title, message);
        }
    }
}


private void showNotificationInADialog(String title, String message) {

    // show a dialog with the provided title and message
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle(title);
    builder.setMessage(message);
    builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            dialog.cancel();
        }
    });
    AlertDialog alert = builder.create();
    alert.show();
}

package com.yourcompany.app;

import android.content.Intent;
import android.util.Log;

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

public class MyFirebaseMessagingService extends FirebaseMessagingService {


    public MyFirebaseMessagingService() {
        super();
    }

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {

        Log.d(Application.APPTAG, "myFirebaseMessagingService - onMessageReceived - message: " + remoteMessage);

        Intent dialogIntent = new Intent(this, NotificationActivity.class);
        dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        dialogIntent.putExtra("msg", remoteMessage);
        startActivity(dialogIntent);

    }

}

package com.yourcompany.app;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.util.Log;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.view.ContextThemeWrapper;

import com.google.firebase.messaging.RemoteMessage;

public class NotificationActivity extends AppCompatActivity {

private Activity context;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    context = this;
    Bundle extras = getIntent().getExtras();

    Log.d(Application.APPTAG, "NotificationActivity - onCreate - extras: " + extras);

    if (extras == null) {
        context.finish();
        return;
    }

    RemoteMessage msg = (RemoteMessage) extras.get("msg");

    if (msg == null) {
        context.finish();
        return;
    }

    RemoteMessage.Notification notification = msg.getNotification();

    if (notification == null) {
        context.finish();
        return;
    }

    String dialogMessage;
    try {
        dialogMessage = notification.getBody();
    } catch (Exception e){
        context.finish();
        return;
    }
    String dialogTitle = notification.getTitle();
    if (dialogTitle == null || dialogTitle.length() == 0) {
        dialogTitle = "";
    }

    AlertDialog.Builder builder = new AlertDialog.Builder(new ContextThemeWrapper(context, R.style.myDialog));
    builder.setTitle(dialogTitle);
    builder.setMessage(dialogMessage);
    builder.setPositiveButton(getResources().getString(R.string.accept), new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            dialog.cancel();
        }
    });
    AlertDialog alert = builder.create();
    alert.show();

}

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

    <meta-data android:name="com.google.firebase.messaging.default_notification_channel_id" android:value="@string/default_notification_channel_id"/>

    <activity android:name=".NotificationActivity"
        android:theme="@style/myDialog"> </activity>

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

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

      // notifications channel creation
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
      // Create channel to show notifications.
      String channelId = getResources().getString("default_channel_id");
      String channelName = getResources().getString("General announcements");
      NotificationManager notificationManager = getSystemService(NotificationManager.class);
      notificationManager.createNotificationChannel(new NotificationChannel(channelId,
              channelName, NotificationManager.IMPORTANCE_LOW));
  }

{ 
  "to": "/path", 
  "data": 
     { 
      "my_custom_key": "my_custom_value", 
      "my_custom_key2": true 
     } 
}

 {
     "notification": {
            "title" : "title",
            "body"  : "body text",
            "icon"  : "ic_notification",
            "click_action" : "OPEN_ACTIVITY_1"
        }
   }

public class MyFirebaseMessagingService extends FirebaseMessagingService {
    …

      @Override public void onMessageReceived(RemoteMessage remoteMessage){
           Map<String, String> data = remoteMessage.getData();
           String myCustomKey = data.get("my_custom_key");
        
       } 

    …

}