FCM notification message are not received in android Oreo version?

When you target Android 8.0 (API level 26), you must implement one or more notification channels. If your targetSdkVersion is set to 25 or lower, when your app runs on Android 8.0 (API level 26) or higher, it behaves the same as it would on devices running Android 7.1 (API level 25) or lower.

Note: If you target Android 8.0 (API level 26) and post a notification without specifying a notification channel, the notification does not appear and the system logs an error.

Note: You can turn on a new setting in Android 8.0 (API level 26) to display an on-screen warning that appears as a toast when an app targeting Android 8.0 (API level 26) attempts to post without a notification channel. To turn on the setting for a development device running Android 8.0 (API level 26), navigate to Settings > Developer options and enable Show notification channel warnings.

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
   NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
   String id = "id_product";
   // The user-visible name of the channel.
   CharSequence name = "Product";
   // The user-visible description of the channel.
   String description = "Notifications regarding our products";
   int importance = NotificationManager.IMPORTANCE_MAX;
   NotificationChannel mChannel = new NotificationChannel(id, name, importance);
   // Configure the notification channel.
   mChannel.setDescription(description);
   mChannel.enableLights(true);
   // Sets the notification light color for notifications posted to this
   // channel, if the device supports this feature.
   mChannel.setLightColor(Color.RED);
   notificationManager.createNotificationChannel(mChannel);
}

Creating a Push Notification on Android Oreo

To create a notification, you will use the NotificationCompat.Builder class. The constructor which was used before took only Context as a parameter, but in Android O, the constructor looks like this –

NotificationCompat.Builder(Context context, String channelId)

The following code snippet will show you how to create a notification –

Intent intent1 = new Intent(getApplicationContext(), Ma

inActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(getApplicationContext(), 123, intent1, PendingIntent.FLAG_UPDATE_CURRENT);
NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(getApplicationContext(),"id_product")
       .setSmallIcon(R.drawable.flatpnicon) //your app icon
       .setBadgeIconType(R.drawable.flatpnicon) //your app icon
       .setChannelId(id)
       .setContentTitle(extras.get("nt").toString())
       .setAutoCancel(true).setContentIntent(pendingIntent)
       .setNumber(1)
       .setColor(255)
       .setContentText(extras.get("nm").toString())
       .setWhen(System.currentTimeMillis());
notificationManager.notify(1, notificationBuilder.build());

Android O gives you a few more functions to customize your notification –

setNumber() – allows you to set the number displayed in the long-press menu setChannelId() – allows you set the Channel Id explicitly if you are using the old constructor setColor() – allows a RGB value to put a color theme for your notification setBadgeIconType() – allows you to set an icon to be displayed in the long-press menu

for more info check example here


"Starting in Android 8.0 (API level 26), all notifications must be assigned to a channel or it will not appear."

Individual notifications must now be put in a specific channel. (Reference)

Option 1 [simple] Change the target android version Android 7.1 (API level 25) or lower.

compileSdkVersion 25
    defaultConfig {
        applicationId "com.fcm"
        minSdkVersion 16
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }

Option 2 If you don't want to change the target version then follow the following method

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
     NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
     NotificationChannel nc = new NotificationChannel(“[enter your product id]”, “[Name]”,NotificationManager.IMPORTANCE_MAX);
     nc.setDescription(“[your description for the notification]”);
     nc.enableLights(true);
     nc.setLightColor(Color.GREEN);
     nm.createNotificationChannel(nc);
  }

Use following Builder constructor

NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(appContext, [id you mentioned above in constructor of NotificationChannel])

Create the notification from the Builder

nm.notify("0", notificationBuilder.build())

  notification = new NotificationCompat.Builder(this, ANDROID_CHANNEL_ID)
                    .setSmallIcon(R.drawable.ic_small_logo)
                    .setLargeIcon(picture)
                    .setContentTitle("Title")
                    .setContentText("Body")
                    .setContentIntent(pendingIntent)
                    .setAutoCancel(true)
                    .build();
  • ANDROID_CHANNEL_ID = "CHANNEL_ID"
  • PendingIntent pendingIntent = PendingIntent.getActivity(getApplicationContext(), 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
  • intent = new Intent(getApplicationContext(), HomeActivity.class); intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);

You can use below class for generating notification in lower and upper version of android(Tested from 4.2(Jelly Bean) to 8.1.1(Oreo)).

public final class NotificationHelper extends Thread {

    private Context context;
    private NotificationManager notifManager;
    private NotificationCompat.Builder notification_compact;
    private Notification.Builder notification_builder;
    private int OREO_NOTIFICATION_TYPE = 2; //setting default notificaiton type 2, as 1 is not for constant updating
    //put string channel name and id in **<>**
    private static final String CHANNEL_ONE_ID = "<Your_channel_string_ID>";
    private static final String CHANNEL_ONE_NAME = "<Your channel_String_NAME>";
    private static final String CHANNEL_TWO_ID = "<Your_channel_string_ID_TWO>";
    private static final String CHANNEL_TWO_NAME = "<Your channel_String_NAME_TWO>";
    private String title = "", message = "";


    /**
     * @param context content of activity
     * @param title   title for notification_compact
     * @param message message to show in notification_compact
     */
    public NotificationHelper(Context context, String title, String message) {
        this.context = context;
        this.title = title;
        this.message = message;
        notifManager = getManager();
    }


    @Override
    public void run() {
        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.N_MR1) {
            //do stuff for oreo
            createChannels();
            postNotificationAboveV25(OREO_NOTIFICATION_TYPE, title);
        } else {
            //do stuff for other versions
            postNotificationUptoV25();
        }
    }


    //method to show notificaiton above nougat
    private void postNotificationAboveV25(int id, String title) {
        notification_builder = getNotificatonBuilder(id, title);

        if (notification_builder != null) {
            getManager().notify(id, notification_builder.build());
        }
    }


    //get pending intent to launch activity
    private PendingIntent getPendingIntent() {

        Intent startActivity = context.getPackageManager()
                .getLaunchIntentForPackage(context.getPackageName())
                .setPackage(null)
                .setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);

        return PendingIntent.getActivity(context, 0, startActivity, 0);

//        Intent resultIntent = new Intent(context, ActionActivity.class);
//        return PendingIntent.getActivity(context, AppHelper.NOTIFICATION_ID, resultIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    }


    //method to get notification builder above nougat
    private Notification.Builder getNotificatonBuilder(int id, String title) {
        switch (id) {
            case 1:
                return notification_builder = getNotification1(title, message);

            case 2:
                return notification_builder = getNotification2(title, message);

            default:
                return notification_builder = getNotification2(title, message);
        }
    }


    //Create the notification_compact that’ll be posted to Channel One
    //use this one if your notification is a type of push notificaiton
    //                              or
    //if you are not updating it in continues intervals like every 4 or 5 seconds(ex. Timer)
    @SuppressLint("NewApi")
    private Notification.Builder getNotification1(String title, String body) {
        return new Notification.Builder(context, CHANNEL_ONE_ID)
                .setContentTitle(title)
                .setContentText(body)
                .setSmallIcon(R.drawable.app_icon)
                .setAutoCancel(true)
                .setTicker(title + AppHelper.getMessage(R.string.started))
                .setColor(AppHelper.getColor(context, R.color.colorPrimary))
                .setContentIntent(getPendingIntent());
    }


    //Create the notification_compact that’ll be posted to Channel Two
    //use this for continues intervals or updating continuesly
    @SuppressLint("NewApi")
    private Notification.Builder getNotification2(String title, String body) {
        return new Notification.Builder(context, CHANNEL_TWO_ID)
                .setContentTitle(title)
                .setContentText(body)
                .setTicker(title + AppHelper.getMessage(R.string.started))
                .setSmallIcon(R.drawable.app_icon)
                .setAutoCancel(true)
                .setColor(AppHelper.getColor(context, R.color.colorPrimary))
                .setContentIntent(getPendingIntent());
    }


    //method to post notification upto Nougat i.e., below api level 26
    @SuppressLint("NewApi")
    private void postNotificationUptoV25() {
        notification_compact = new NotificationCompat.Builder(context);
        notification_compact.setAutoCancel(true);
        notification_compact.setSmallIcon(R.drawable.app_icon);
        notification_compact.setTicker(title + AppHelper.getMessage(R.string.started));
        notification_compact.setContentTitle(title);
        notification_compact.setContentText(message);
        notification_compact.setColor(AppHelper.getColor(context, R.color.colorPrimary));
        notification_compact.setContentIntent(getPendingIntent());
//        notification_compact.setWhen(1506067106762L);

        getManager().notify(AppHelper.NOTIFICATION_ID, notification_compact.build());
    }


    //method to update notification
    public void updateNotification(String time) {

        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.N_MR1) {
            //update above NOUGAT V25
            if (notification_builder != null) {
                notification_builder.setContentText(message + "  " + time);
                getManager().notify(AppHelper.NOTIFICATION_ID, notification_builder.build());
            }
        } else {
            //update below NOUGAT V25
            if (notification_compact != null) {
                notification_compact.setContentText(message + "  " + time);
                getManager().notify(AppHelper.NOTIFICATION_ID, notification_compact.build());
            }
        }
    }

    //method to update remainting notification
    public void updateRemainingNotification(String time) {

        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.N_MR1) {
            //update above NOUGAT V25
            if (notification_builder != null) {
                notification_builder.setContentText(time + AppHelper.getMessage(R.string.remaining));
                getManager().notify(AppHelper.NOTIFICATION_ID, notification_builder.build());
            }
        } else {
            //update below NOUGAT V25
            if (notification_compact != null) {
                notification_compact.setContentText(time + AppHelper.getMessage(R.string.remaining));
                getManager().notify(AppHelper.NOTIFICATION_ID, notification_compact.build());
            }
        }
    }


    //method to create channels which is necessary above Nougat(API - 25) i.e., at Oreo(API - 26)
    @SuppressLint("NewApi")
    private void createChannels() {

        NotificationChannel notificationChannel = new NotificationChannel(CHANNEL_ONE_ID,
                CHANNEL_ONE_NAME, notifManager.IMPORTANCE_DEFAULT);
        notificationChannel.enableLights(true);
        notificationChannel.setLightColor(Color.RED);
        notificationChannel.setShowBadge(true);
        notificationChannel.setLockscreenVisibility(Notification.VISIBILITY_PUBLIC);
        getManager().createNotificationChannel(notificationChannel);

        NotificationChannel notificationChannel2 = new NotificationChannel(CHANNEL_TWO_ID,
                CHANNEL_TWO_NAME, notifManager.IMPORTANCE_DEFAULT);
        notificationChannel2.enableLights(false);
        notificationChannel2.enableVibration(true);
        notificationChannel2.setLightColor(Color.RED);
        notificationChannel2.setShowBadge(false);
        getManager().createNotificationChannel(notificationChannel2);

    }


    //method to get Object of Notification Manager
    private NotificationManager getManager() {
        if (notifManager == null)
            notifManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        return notifManager;
    }


    /**
     * call this method to destroy notification
     */
    public void destroyNotification() {
        if (notifManager != null)
            notifManager.cancel(AppHelper.NOTIFICATION_ID);
    }
}

Just call this class from FCM, with context and msg. As its a thread class you can update the notification constantly also.

Don't forget to call destroyNotification() method, when your work ends.

You can discover and make changes in it, as you like